This is dash.info, produced by makeinfo version 6.7 from dash.texi. This manual is for Dash version 2.19.1. Copyright © 2012–2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being “GNU General Public License,” and no Front-Cover Texts or Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”. INFO-DIR-SECTION Emacs START-INFO-DIR-ENTRY * Dash: (dash.info). A modern list library for GNU Emacs. END-INFO-DIR-ENTRY  File: dash.info, Node: Top, Next: Installation, Up: (dir) Dash **** This manual is for Dash version 2.19.1. Copyright © 2012–2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being “GNU General Public License,” and no Front-Cover Texts or Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”. * Menu: * Installation:: Installing and configuring Dash. * Functions:: Dash API reference. * Development:: Contributing to Dash development. Appendices * FDL:: The license for this documentation. * GPL:: Conditions for copying and changing Dash. * Index:: Index including functions and macros. — The Detailed Node Listing — Installation * Using in a package:: Listing Dash as a package dependency. * Fontification of special variables:: Font Lock of anaphoric macro variables. * Info symbol lookup:: Looking up Dash symbols in this manual. Functions * Maps:: * Sublist selection:: * List to list:: * Reductions:: * Unfolding:: * Predicates:: * Partitioning:: * Indexing:: * Set operations:: * Other list operations:: * Tree operations:: * Threading macros:: * Binding:: * Side effects:: * Destructive operations:: * Function combinators:: Development * Contribute:: How to contribute. * Contributors:: List of contributors.  File: dash.info, Node: Installation, Next: Functions, Prev: Top, Up: Top 1 Installation ************** Dash is available on GNU ELPA (https://elpa.gnu.org/), GNU-devel ELPA (https://elpa.gnu.org/devel/), and MELPA (https://melpa.org/), and can be installed with the standard command ‘package-install’ (*note (emacs)Package Installation::). ‘M-x package-install dash ’ Install the Dash library. Alternatively, you can just dump ‘dash.el’ in your ‘load-path’ somewhere (*note (emacs)Lisp Libraries::). * Menu: * Using in a package:: Listing Dash as a package dependency. * Fontification of special variables:: Font Lock of anaphoric macro variables. * Info symbol lookup:: Looking up Dash symbols in this manual.  File: dash.info, Node: Using in a package, Next: Fontification of special variables, Up: Installation 1.1 Using in a package ====================== If you use Dash in your own package, be sure to list it as a dependency in the library’s headers as follows (*note (elisp)Library Headers::). ;; Package-Requires: ((dash "2.19.1"))  File: dash.info, Node: Fontification of special variables, Next: Info symbol lookup, Prev: Using in a package, Up: Installation 1.2 Fontification of special variables ====================================== The autoloaded minor mode ‘dash-fontify-mode’ is provided for optional fontification of anaphoric Dash variables (‘it’, ‘acc’, etc.) in Emacs Lisp buffers using search-based Font Lock (*note (emacs)Font Lock::). In older Emacs versions which do not dynamically detect macros, the minor mode also fontifies calls to Dash macros. To automatically enable the minor mode in all Emacs Lisp buffers, just call its autoloaded global counterpart ‘global-dash-fontify-mode’, either interactively or from your ‘user-init-file’: (global-dash-fontify-mode)  File: dash.info, Node: Info symbol lookup, Prev: Fontification of special variables, Up: Installation 1.3 Info symbol lookup ====================== While editing Elisp files, you can use ‘C-h S’ (‘info-lookup-symbol’) to look up Elisp symbols in the relevant Info manuals (*note (emacs)Info Lookup::). To enable the same for Dash symbols, use the command ‘dash-register-info-lookup’. It can be called directly when needed, or automatically from your ‘user-init-file’. For example: (with-eval-after-load 'info-look (dash-register-info-lookup))  File: dash.info, Node: Functions, Next: Development, Prev: Installation, Up: Top 2 Functions *********** This chapter contains reference documentation for the Dash API (Application Programming Interface). The names of all public functions defined in the library are prefixed with a dash character (‘-’). The library also provides anaphoric macro versions of functions where that makes sense. The names of these macros are prefixed with two dashes (‘--’) instead of one. For instance, while the function ‘-map’ applies a function to each element of a list, its anaphoric counterpart ‘--map’ evaluates a form with the local variable ‘it’ temporarily bound to the current list element instead. ;; Normal version. (-map (lambda (n) (* n n)) '(1 2 3 4)) ⇒ (1 4 9 16) ;; Anaphoric version. (--map (* it it) '(1 2 3 4)) ⇒ (1 4 9 16) The normal version can, of course, also be written as in the following example, which demonstrates the utility of both versions. (defun my-square (n) "Return N multiplied by itself." (* n n)) (-map #'my-square '(1 2 3 4)) ⇒ (1 4 9 16) * Menu: * Maps:: * Sublist selection:: * List to list:: * Reductions:: * Unfolding:: * Predicates:: * Partitioning:: * Indexing:: * Set operations:: * Other list operations:: * Tree operations:: * Threading macros:: * Binding:: * Side effects:: * Destructive operations:: * Function combinators::  File: dash.info, Node: Maps, Next: Sublist selection, Up: Functions 2.1 Maps ======== Functions in this category take a transforming function, which is then applied sequentially to each or selected elements of the input list. The results are collected in order and returned as a new list. -- Function: -map (fn list) Apply FN to each item in LIST and return the list of results. This function’s anaphoric counterpart is ‘--map’. (-map (lambda (num) (* num num)) '(1 2 3 4)) ⇒ (1 4 9 16) (-map #'1+ '(1 2 3 4)) ⇒ (2 3 4 5) (--map (* it it) '(1 2 3 4)) ⇒ (1 4 9 16) -- Function: -map-when (pred rep list) Use PRED to conditionally apply REP to each item in LIST. Return a copy of LIST where the items for which PRED returns ‘nil’ are unchanged, and the rest are mapped through the REP function. Alias: ‘-replace-where’ See also: ‘-update-at’ (*note -update-at::) (-map-when 'even? 'square '(1 2 3 4)) ⇒ (1 4 3 16) (--map-when (> it 2) (* it it) '(1 2 3 4)) ⇒ (1 2 9 16) (--map-when (= it 2) 17 '(1 2 3 4)) ⇒ (1 17 3 4) -- Function: -map-first (pred rep list) Use PRED to determine the first item in LIST to call REP on. Return a copy of LIST where the first item for which PRED returns non-‘nil’ is replaced with the result of calling REP on that item. See also: ‘-map-when’ (*note -map-when::), ‘-replace-first’ (*note -replace-first::) (-map-first 'even? 'square '(1 2 3 4)) ⇒ (1 4 3 4) (--map-first (> it 2) (* it it) '(1 2 3 4)) ⇒ (1 2 9 4) (--map-first (= it 2) 17 '(1 2 3 2)) ⇒ (1 17 3 2) -- Function: -map-last (pred rep list) Use PRED to determine the last item in LIST to call REP on. Return a copy of LIST where the last item for which PRED returns non-‘nil’ is replaced with the result of calling REP on that item. See also: ‘-map-when’ (*note -map-when::), ‘-replace-last’ (*note -replace-last::) (-map-last 'even? 'square '(1 2 3 4)) ⇒ (1 2 3 16) (--map-last (> it 2) (* it it) '(1 2 3 4)) ⇒ (1 2 3 16) (--map-last (= it 2) 17 '(1 2 3 2)) ⇒ (1 2 3 17) -- Function: -map-indexed (fn list) Apply FN to each index and item in LIST and return the list of results. This is like ‘-map’ (*note -map::), but FN takes two arguments: the index of the current element within LIST, and the element itself. This function’s anaphoric counterpart is ‘--map-indexed’. For a side-effecting variant, see also ‘-each-indexed’ (*note -each-indexed::). (-map-indexed (lambda (index item) (- item index)) '(1 2 3 4)) ⇒ (1 1 1 1) (--map-indexed (- it it-index) '(1 2 3 4)) ⇒ (1 1 1 1) (-map-indexed #'* '(1 2 3 4)) ⇒ (0 2 6 12) -- Function: -annotate (fn list) Pair each item in LIST with the result of passing it to FN. Return an alist of (RESULT . ITEM), where each ITEM is the corresponding element of LIST, and RESULT is the value obtained by calling FN on ITEM. This function’s anaphoric counterpart is ‘--annotate’. (-annotate #'1+ '(1 2 3)) ⇒ ((2 . 1) (3 . 2) (4 . 3)) (-annotate #'length '((f o o) (bar baz))) ⇒ ((3 f o o) (2 bar baz)) (--annotate (> it 1) '(0 1 2 3)) ⇒ ((nil . 0) (nil . 1) (t . 2) (t . 3)) -- Function: -splice (pred fun list) Splice lists generated by FUN in place of items satisfying PRED in LIST. Call PRED on each element of LIST. Whenever the result of PRED is ‘nil’, leave that ‘it’ as-is. Otherwise, call FUN on the same ‘it’ that satisfied PRED. The result should be a (possibly empty) list of items to splice in place of ‘it’ in LIST. This can be useful as an alternative to the ‘,@’ construct in a ‘`’ structure, in case you need to splice several lists at marked positions (for example with keywords). This function’s anaphoric counterpart is ‘--splice’. See also: ‘-splice-list’ (*note -splice-list::), ‘-insert-at’ (*note -insert-at::). (-splice #'numberp (lambda (n) (list n n)) '(a 1 b 2)) ⇒ (a 1 1 b 2 2) (--splice t (list it it) '(1 2 3 4)) ⇒ (1 1 2 2 3 3 4 4) (--splice (eq it :magic) '((magical) (code)) '((foo) :magic (bar))) ⇒ ((foo) (magical) (code) (bar)) -- Function: -splice-list (pred new-list list) Splice NEW-LIST in place of elements matching PRED in LIST. See also: ‘-splice’ (*note -splice::), ‘-insert-at’ (*note -insert-at::) (-splice-list 'keywordp '(a b c) '(1 :foo 2)) ⇒ (1 a b c 2) (-splice-list 'keywordp nil '(1 :foo 2)) ⇒ (1 2) (--splice-list (keywordp it) '(a b c) '(1 :foo 2)) ⇒ (1 a b c 2) -- Function: -mapcat (fn list) Return the concatenation of the result of mapping FN over LIST. Thus function FN should return a list. (-mapcat 'list '(1 2 3)) ⇒ (1 2 3) (-mapcat (lambda (item) (list 0 item)) '(1 2 3)) ⇒ (0 1 0 2 0 3) (--mapcat (list 0 it) '(1 2 3)) ⇒ (0 1 0 2 0 3) -- Function: -copy (list) Create a shallow copy of LIST. (-copy '(1 2 3)) ⇒ (1 2 3) (let ((a '(1 2 3))) (eq a (-copy a))) ⇒ nil  File: dash.info, Node: Sublist selection, Next: List to list, Prev: Maps, Up: Functions 2.2 Sublist selection ===================== Functions returning a sublist of the original list. -- Function: -filter (pred list) Return a new list of the items in LIST for which PRED returns non-‘nil’. Alias: ‘-select’. This function’s anaphoric counterpart is ‘--filter’. For similar operations, see also ‘-keep’ (*note -keep::) and ‘-remove’ (*note -remove::). (-filter (lambda (num) (= 0 (% num 2))) '(1 2 3 4)) ⇒ (2 4) (-filter #'natnump '(-2 -1 0 1 2)) ⇒ (0 1 2) (--filter (= 0 (% it 2)) '(1 2 3 4)) ⇒ (2 4) -- Function: -remove (pred list) Return a new list of the items in LIST for which PRED returns ‘nil’. Alias: ‘-reject’. This function’s anaphoric counterpart is ‘--remove’. For similar operations, see also ‘-keep’ (*note -keep::) and ‘-filter’ (*note -filter::). (-remove (lambda (num) (= 0 (% num 2))) '(1 2 3 4)) ⇒ (1 3) (-remove #'natnump '(-2 -1 0 1 2)) ⇒ (-2 -1) (--remove (= 0 (% it 2)) '(1 2 3 4)) ⇒ (1 3) -- Function: -remove-first (pred list) Remove the first item from LIST for which PRED returns non-‘nil’. This is a non-destructive operation, but only the front of LIST leading up to the removed item is a copy; the rest is LIST’s original tail. If no item is removed, then the result is a complete copy. Alias: ‘-reject-first’. This function’s anaphoric counterpart is ‘--remove-first’. See also ‘-map-first’ (*note -map-first::), ‘-remove-item’ (*note -remove-item::), and ‘-remove-last’ (*note -remove-last::). (-remove-first #'natnump '(-2 -1 0 1 2)) ⇒ (-2 -1 1 2) (-remove-first #'stringp '(1 2 "first" "second")) ⇒ (1 2 "second") (--remove-first (> it 3) '(1 2 3 4 5 6)) ⇒ (1 2 3 5 6) -- Function: -remove-last (pred list) Remove the last item from LIST for which PRED returns non-‘nil’. The result is a copy of LIST regardless of whether an element is removed. Alias: ‘-reject-last’. This function’s anaphoric counterpart is ‘--remove-last’. See also ‘-map-last’ (*note -map-last::), ‘-remove-item’ (*note -remove-item::), and ‘-remove-first’ (*note -remove-first::). (-remove-last #'natnump '(1 3 5 4 7 8 10 -11)) ⇒ (1 3 5 4 7 8 -11) (-remove-last #'stringp '(1 2 "last" "second")) ⇒ (1 2 "last") (--remove-last (> it 3) '(1 2 3 4 5 6 7 8 9 10)) ⇒ (1 2 3 4 5 6 7 8 9) -- Function: -remove-item (item list) Return a copy of LIST with all occurrences of ITEM removed. The comparison is done with ‘equal’. (-remove-item 3 '(1 2 3 2 3 4 5 3)) ⇒ (1 2 2 4 5) (-remove-item 'foo '(foo bar baz foo)) ⇒ (bar baz) (-remove-item "bob" '("alice" "bob" "eve" "bob")) ⇒ ("alice" "eve") -- Function: -non-nil (list) Return a copy of LIST with all ‘nil’ items removed. (-non-nil '(nil 1 nil 2 nil nil 3 4 nil 5 nil)) ⇒ (1 2 3 4 5) (-non-nil '((nil))) ⇒ ((nil)) (-non-nil ()) ⇒ () -- Function: -slice (list from &optional to step) Return copy of LIST, starting from index FROM to index TO. FROM or TO may be negative. These values are then interpreted modulo the length of the list. If STEP is a number, only each STEPth item in the resulting section is returned. Defaults to 1. (-slice '(1 2 3 4 5) 1) ⇒ (2 3 4 5) (-slice '(1 2 3 4 5) 0 3) ⇒ (1 2 3) (-slice '(1 2 3 4 5 6 7 8 9) 1 -1 2) ⇒ (2 4 6 8) -- Function: -take (n list) Return a copy of the first N items in LIST. Return a copy of LIST if it contains N items or fewer. Return ‘nil’ if N is zero or less. See also: ‘-take-last’ (*note -take-last::). (-take 3 '(1 2 3 4 5)) ⇒ (1 2 3) (-take 17 '(1 2 3 4 5)) ⇒ (1 2 3 4 5) (-take 0 '(1 2 3 4 5)) ⇒ () -- Function: -take-last (n list) Return a copy of the last N items of LIST in order. Return a copy of LIST if it contains N items or fewer. Return ‘nil’ if N is zero or less. See also: ‘-take’ (*note -take::). (-take-last 3 '(1 2 3 4 5)) ⇒ (3 4 5) (-take-last 17 '(1 2 3 4 5)) ⇒ (1 2 3 4 5) (-take-last 1 '(1 2 3 4 5)) ⇒ (5) -- Function: -drop (n list) Return the tail (not a copy) of LIST without the first N items. Return ‘nil’ if LIST contains N items or fewer. Return LIST if N is zero or less. For another variant, see also ‘-drop-last’ (*note -drop-last::). (-drop 3 '(1 2 3 4 5)) ⇒ (4 5) (-drop 17 '(1 2 3 4 5)) ⇒ () (-drop 0 '(1 2 3 4 5)) ⇒ (1 2 3 4 5) -- Function: -drop-last (n list) Return a copy of LIST without its last N items. Return a copy of LIST if N is zero or less. Return ‘nil’ if LIST contains N items or fewer. See also: ‘-drop’ (*note -drop::). (-drop-last 3 '(1 2 3 4 5)) ⇒ (1 2) (-drop-last 17 '(1 2 3 4 5)) ⇒ () (-drop-last 0 '(1 2 3 4 5)) ⇒ (1 2 3 4 5) -- Function: -take-while (pred list) Take successive items from LIST for which PRED returns non-‘nil’. PRED is a function of one argument. Return a new list of the successive elements from the start of LIST for which PRED returns non-‘nil’. This function’s anaphoric counterpart is ‘--take-while’. For another variant, see also ‘-drop-while’ (*note -drop-while::). (-take-while #'even? '(1 2 3 4)) ⇒ () (-take-while #'even? '(2 4 5 6)) ⇒ (2 4) (--take-while (< it 4) '(1 2 3 4 3 2 1)) ⇒ (1 2 3) -- Function: -drop-while (pred list) Drop successive items from LIST for which PRED returns non-‘nil’. PRED is a function of one argument. Return the tail (not a copy) of LIST starting from its first element for which PRED returns ‘nil’. This function’s anaphoric counterpart is ‘--drop-while’. For another variant, see also ‘-take-while’ (*note -take-while::). (-drop-while #'even? '(1 2 3 4)) ⇒ (1 2 3 4) (-drop-while #'even? '(2 4 5 6)) ⇒ (5 6) (--drop-while (< it 4) '(1 2 3 4 3 2 1)) ⇒ (4 3 2 1) -- Function: -select-by-indices (indices list) Return a list whose elements are elements from LIST selected as ‘(nth i list)‘ for all i from INDICES. (-select-by-indices '(4 10 2 3 6) '("v" "e" "l" "o" "c" "i" "r" "a" "p" "t" "o" "r")) ⇒ ("c" "o" "l" "o" "r") (-select-by-indices '(2 1 0) '("a" "b" "c")) ⇒ ("c" "b" "a") (-select-by-indices '(0 1 2 0 1 3 3 1) '("f" "a" "r" "l")) ⇒ ("f" "a" "r" "f" "a" "l" "l" "a") -- Function: -select-columns (columns table) Select COLUMNS from TABLE. TABLE is a list of lists where each element represents one row. It is assumed each row has the same length. Each row is transformed such that only the specified COLUMNS are selected. See also: ‘-select-column’ (*note -select-column::), ‘-select-by-indices’ (*note -select-by-indices::) (-select-columns '(0 2) '((1 2 3) (a b c) (:a :b :c))) ⇒ ((1 3) (a c) (:a :c)) (-select-columns '(1) '((1 2 3) (a b c) (:a :b :c))) ⇒ ((2) (b) (:b)) (-select-columns nil '((1 2 3) (a b c) (:a :b :c))) ⇒ (nil nil nil) -- Function: -select-column (column table) Select COLUMN from TABLE. TABLE is a list of lists where each element represents one row. It is assumed each row has the same length. The single selected column is returned as a list. See also: ‘-select-columns’ (*note -select-columns::), ‘-select-by-indices’ (*note -select-by-indices::) (-select-column 1 '((1 2 3) (a b c) (:a :b :c))) ⇒ (2 b :b)  File: dash.info, Node: List to list, Next: Reductions, Prev: Sublist selection, Up: Functions 2.3 List to list ================ Functions returning a modified copy of the input list. -- Function: -keep (fn list) Return a new list of the non-‘nil’ results of applying FN to each item in LIST. Like ‘-filter’ (*note -filter::), but returns the non-‘nil’ results of FN instead of the corresponding elements of LIST. Its anaphoric counterpart is ‘--keep’. (-keep #'cdr '((1 2 3) (4 5) (6))) ⇒ ((2 3) (5)) (-keep (lambda (n) (and (> n 3) (* 10 n))) '(1 2 3 4 5 6)) ⇒ (40 50 60) (--keep (and (> it 3) (* 10 it)) '(1 2 3 4 5 6)) ⇒ (40 50 60) -- Function: -concat (&rest sequences) Concatenate all the arguments and make the result a list. The result is a list whose elements are the elements of all the arguments. Each argument may be a list, vector or string. All arguments except the last argument are copied. The last argument is just used as the tail of the new list. (-concat '(1)) ⇒ (1) (-concat '(1) '(2)) ⇒ (1 2) (-concat '(1) '(2 3) '(4)) ⇒ (1 2 3 4) -- Function: -flatten (l) Take a nested list L and return its contents as a single, flat list. Note that because ‘nil’ represents a list of zero elements (an empty list), any mention of ‘nil’ in L will disappear after flattening. If you need to preserve nils, consider ‘-flatten-n’ (*note -flatten-n::) or map them to some unique symbol and then map them back. Conses of two atoms are considered "terminals", that is, they aren’t flattened further. See also: ‘-flatten-n’ (*note -flatten-n::) (-flatten '((1))) ⇒ (1) (-flatten '((1 (2 3) (((4 (5))))))) ⇒ (1 2 3 4 5) (-flatten '(1 2 (3 . 4))) ⇒ (1 2 (3 . 4)) -- Function: -flatten-n (num list) Flatten NUM levels of a nested LIST. See also: ‘-flatten’ (*note -flatten::) (-flatten-n 1 '((1 2) ((3 4) ((5 6))))) ⇒ (1 2 (3 4) ((5 6))) (-flatten-n 2 '((1 2) ((3 4) ((5 6))))) ⇒ (1 2 3 4 (5 6)) (-flatten-n 3 '((1 2) ((3 4) ((5 6))))) ⇒ (1 2 3 4 5 6) -- Function: -replace (old new list) Replace all OLD items in LIST with NEW. Elements are compared using ‘equal’. See also: ‘-replace-at’ (*note -replace-at::) (-replace 1 "1" '(1 2 3 4 3 2 1)) ⇒ ("1" 2 3 4 3 2 "1") (-replace "foo" "bar" '("a" "nice" "foo" "sentence" "about" "foo")) ⇒ ("a" "nice" "bar" "sentence" "about" "bar") (-replace 1 2 nil) ⇒ nil -- Function: -replace-first (old new list) Replace the first occurrence of OLD with NEW in LIST. Elements are compared using ‘equal’. See also: ‘-map-first’ (*note -map-first::) (-replace-first 1 "1" '(1 2 3 4 3 2 1)) ⇒ ("1" 2 3 4 3 2 1) (-replace-first "foo" "bar" '("a" "nice" "foo" "sentence" "about" "foo")) ⇒ ("a" "nice" "bar" "sentence" "about" "foo") (-replace-first 1 2 nil) ⇒ nil -- Function: -replace-last (old new list) Replace the last occurrence of OLD with NEW in LIST. Elements are compared using ‘equal’. See also: ‘-map-last’ (*note -map-last::) (-replace-last 1 "1" '(1 2 3 4 3 2 1)) ⇒ (1 2 3 4 3 2 "1") (-replace-last "foo" "bar" '("a" "nice" "foo" "sentence" "about" "foo")) ⇒ ("a" "nice" "foo" "sentence" "about" "bar") (-replace-last 1 2 nil) ⇒ nil -- Function: -insert-at (n x list) Return a list with X inserted into LIST at position N. See also: ‘-splice’ (*note -splice::), ‘-splice-list’ (*note -splice-list::) (-insert-at 1 'x '(a b c)) ⇒ (a x b c) (-insert-at 12 'x '(a b c)) ⇒ (a b c x) -- Function: -replace-at (n x list) Return a list with element at Nth position in LIST replaced with X. See also: ‘-replace’ (*note -replace::) (-replace-at 0 9 '(0 1 2 3 4 5)) ⇒ (9 1 2 3 4 5) (-replace-at 1 9 '(0 1 2 3 4 5)) ⇒ (0 9 2 3 4 5) (-replace-at 4 9 '(0 1 2 3 4 5)) ⇒ (0 1 2 3 9 5) -- Function: -update-at (n func list) Use FUNC to update the Nth element of LIST. Return a copy of LIST where the Nth element is replaced with the result of calling FUNC on it. See also: ‘-map-when’ (*note -map-when::) (-update-at 0 (lambda (x) (+ x 9)) '(0 1 2 3 4 5)) ⇒ (9 1 2 3 4 5) (-update-at 1 (lambda (x) (+ x 8)) '(0 1 2 3 4 5)) ⇒ (0 9 2 3 4 5) (--update-at 2 (length it) '("foo" "bar" "baz" "quux")) ⇒ ("foo" "bar" 3 "quux") -- Function: -remove-at (n list) Return LIST with its element at index N removed. That is, remove any element selected as (nth N LIST) from LIST and return the result. This is a non-destructive operation: parts of LIST (but not necessarily all of it) are copied as needed to avoid destructively modifying it. See also: ‘-remove-at-indices’ (*note -remove-at-indices::), ‘-remove’ (*note -remove::). (-remove-at 0 '(a b c)) ⇒ (b c) (-remove-at 1 '(a b c)) ⇒ (a c) (-remove-at 2 '(a b c)) ⇒ (a b) -- Function: -remove-at-indices (indices list) Return LIST with its elements at INDICES removed. That is, for each index I in INDICES, remove any element selected as (nth I LIST) from LIST. This is a non-destructive operation: parts of LIST (but not necessarily all of it) are copied as needed to avoid destructively modifying it. See also: ‘-remove-at’ (*note -remove-at::), ‘-remove’ (*note -remove::). (-remove-at-indices '(0) '(a b c d e)) ⇒ (b c d e) (-remove-at-indices '(1 3) '(a b c d e)) ⇒ (a c e) (-remove-at-indices '(4 0 2) '(a b c d e)) ⇒ (b d)  File: dash.info, Node: Reductions, Next: Unfolding, Prev: List to list, Up: Functions 2.4 Reductions ============== Functions reducing lists to a single value (which may also be a list). -- Function: -reduce-from (fn init list) Reduce the function FN across LIST, starting with INIT. Return the result of applying FN to INIT and the first element of LIST, then applying FN to that result and the second element, etc. If LIST is empty, return INIT without calling FN. This function’s anaphoric counterpart is ‘--reduce-from’. For other folds, see also ‘-reduce’ (*note -reduce::) and ‘-reduce-r’ (*note -reduce-r::). (-reduce-from #'- 10 '(1 2 3)) ⇒ 4 (-reduce-from #'list 10 '(1 2 3)) ⇒ (((10 1) 2) 3) (--reduce-from (concat acc " " it) "START" '("a" "b" "c")) ⇒ "START a b c" -- Function: -reduce-r-from (fn init list) Reduce the function FN across LIST in reverse, starting with INIT. Return the result of applying FN to the last element of LIST and INIT, then applying FN to the second-to-last element and the previous result of FN, etc. That is, the first argument of FN is the current element, and its second argument the accumulated value. If LIST is empty, return INIT without calling FN. This function is like ‘-reduce-from’ (*note -reduce-from::) but the operation associates from the right rather than left. In other words, it starts from the end of LIST and flips the arguments to FN. Conceptually, it is like replacing the conses in LIST with applications of FN, and its last link with INIT, and evaluating the resulting expression. This function’s anaphoric counterpart is ‘--reduce-r-from’. For other folds, see also ‘-reduce-r’ (*note -reduce-r::) and ‘-reduce’ (*note -reduce::). (-reduce-r-from #'- 10 '(1 2 3)) ⇒ -8 (-reduce-r-from #'list 10 '(1 2 3)) ⇒ (1 (2 (3 10))) (--reduce-r-from (concat it " " acc) "END" '("a" "b" "c")) ⇒ "a b c END" -- Function: -reduce (fn list) Reduce the function FN across LIST. Return the result of applying FN to the first two elements of LIST, then applying FN to that result and the third element, etc. If LIST contains a single element, return it without calling FN. If LIST is empty, return the result of calling FN with no arguments. This function’s anaphoric counterpart is ‘--reduce’. For other folds, see also ‘-reduce-from’ (*note -reduce-from::) and ‘-reduce-r’ (*note -reduce-r::). (-reduce #'- '(1 2 3 4)) ⇒ -8 (-reduce #'list '(1 2 3 4)) ⇒ (((1 2) 3) 4) (--reduce (format "%s-%d" acc it) '(1 2 3)) ⇒ "1-2-3" -- Function: -reduce-r (fn list) Reduce the function FN across LIST in reverse. Return the result of applying FN to the last two elements of LIST, then applying FN to the third-to-last element and the previous result of FN, etc. That is, the first argument of FN is the current element, and its second argument the accumulated value. If LIST contains a single element, return it without calling FN. If LIST is empty, return the result of calling FN with no arguments. This function is like ‘-reduce’ (*note -reduce::) but the operation associates from the right rather than left. In other words, it starts from the end of LIST and flips the arguments to FN. Conceptually, it is like replacing the conses in LIST with applications of FN, ignoring its last link, and evaluating the resulting expression. This function’s anaphoric counterpart is ‘--reduce-r’. For other folds, see also ‘-reduce-r-from’ (*note -reduce-r-from::) and ‘-reduce’ (*note -reduce::). (-reduce-r #'- '(1 2 3 4)) ⇒ -2 (-reduce-r #'list '(1 2 3 4)) ⇒ (1 (2 (3 4))) (--reduce-r (format "%s-%d" acc it) '(1 2 3)) ⇒ "3-2-1" -- Function: -reductions-from (fn init list) Return a list of FN’s intermediate reductions across LIST. That is, a list of the intermediate values of the accumulator when ‘-reduce-from’ (*note -reduce-from::) (which see) is called with the same arguments. This function’s anaphoric counterpart is ‘--reductions-from’. For other folds, see also ‘-reductions’ (*note -reductions::) and ‘-reductions-r’ (*note -reductions-r::). (-reductions-from #'max 0 '(2 1 4 3)) ⇒ (0 2 2 4 4) (-reductions-from #'* 1 '(1 2 3 4)) ⇒ (1 1 2 6 24) (--reductions-from (format "(FN %s %d)" acc it) "INIT" '(1 2 3)) ⇒ ("INIT" "(FN INIT 1)" "(FN (FN INIT 1) 2)" "(FN (FN (FN INIT 1) 2) 3)") -- Function: -reductions-r-from (fn init list) Return a list of FN’s intermediate reductions across reversed LIST. That is, a list of the intermediate values of the accumulator when ‘-reduce-r-from’ (*note -reduce-r-from::) (which see) is called with the same arguments. This function’s anaphoric counterpart is ‘--reductions-r-from’. For other folds, see also ‘-reductions’ (*note -reductions::) and ‘-reductions-r’ (*note -reductions-r::). (-reductions-r-from #'max 0 '(2 1 4 3)) ⇒ (4 4 4 3 0) (-reductions-r-from #'* 1 '(1 2 3 4)) ⇒ (24 24 12 4 1) (--reductions-r-from (format "(FN %d %s)" it acc) "INIT" '(1 2 3)) ⇒ ("(FN 1 (FN 2 (FN 3 INIT)))" "(FN 2 (FN 3 INIT))" "(FN 3 INIT)" "INIT") -- Function: -reductions (fn list) Return a list of FN’s intermediate reductions across LIST. That is, a list of the intermediate values of the accumulator when ‘-reduce’ (*note -reduce::) (which see) is called with the same arguments. This function’s anaphoric counterpart is ‘--reductions’. For other folds, see also ‘-reductions’ (*note -reductions::) and ‘-reductions-r’ (*note -reductions-r::). (-reductions #'+ '(1 2 3 4)) ⇒ (1 3 6 10) (-reductions #'* '(1 2 3 4)) ⇒ (1 2 6 24) (--reductions (format "(FN %s %d)" acc it) '(1 2 3)) ⇒ (1 "(FN 1 2)" "(FN (FN 1 2) 3)") -- Function: -reductions-r (fn list) Return a list of FN’s intermediate reductions across reversed LIST. That is, a list of the intermediate values of the accumulator when ‘-reduce-r’ (*note -reduce-r::) (which see) is called with the same arguments. This function’s anaphoric counterpart is ‘--reductions-r’. For other folds, see also ‘-reductions-r-from’ (*note -reductions-r-from::) and ‘-reductions’ (*note -reductions::). (-reductions-r #'+ '(1 2 3 4)) ⇒ (10 9 7 4) (-reductions-r #'* '(1 2 3 4)) ⇒ (24 24 12 4) (--reductions-r (format "(FN %d %s)" it acc) '(1 2 3)) ⇒ ("(FN 1 (FN 2 3))" "(FN 2 3)" 3) -- Function: -count (pred list) Counts the number of items in LIST where (PRED item) is non-‘nil’. (-count 'even? '(1 2 3 4 5)) ⇒ 2 (--count (< it 4) '(1 2 3 4)) ⇒ 3 -- Function: -sum (list) Return the sum of LIST. (-sum ()) ⇒ 0 (-sum '(1)) ⇒ 1 (-sum '(1 2 3 4)) ⇒ 10 -- Function: -running-sum (list) Return a list with running sums of items in LIST. LIST must be non-empty. (-running-sum '(1 2 3 4)) ⇒ (1 3 6 10) (-running-sum '(1)) ⇒ (1) (-running-sum ()) error→ Wrong type argument: consp, nil -- Function: -product (list) Return the product of LIST. (-product ()) ⇒ 1 (-product '(1)) ⇒ 1 (-product '(1 2 3 4)) ⇒ 24 -- Function: -running-product (list) Return a list with running products of items in LIST. LIST must be non-empty. (-running-product '(1 2 3 4)) ⇒ (1 2 6 24) (-running-product '(1)) ⇒ (1) (-running-product ()) error→ Wrong type argument: consp, nil -- Function: -inits (list) Return all prefixes of LIST. (-inits '(1 2 3 4)) ⇒ (nil (1) (1 2) (1 2 3) (1 2 3 4)) (-inits nil) ⇒ (nil) (-inits '(1)) ⇒ (nil (1)) -- Function: -tails (list) Return all suffixes of LIST (-tails '(1 2 3 4)) ⇒ ((1 2 3 4) (2 3 4) (3 4) (4) nil) (-tails nil) ⇒ (nil) (-tails '(1)) ⇒ ((1) nil) -- Function: -common-prefix (&rest lists) Return the longest common prefix of LISTS. (-common-prefix '(1)) ⇒ (1) (-common-prefix '(1 2) '(3 4) '(1 2)) ⇒ () (-common-prefix '(1 2) '(1 2 3) '(1 2 3 4)) ⇒ (1 2) -- Function: -common-suffix (&rest lists) Return the longest common suffix of LISTS. (-common-suffix '(1)) ⇒ (1) (-common-suffix '(1 2) '(3 4) '(1 2)) ⇒ () (-common-suffix '(1 2 3 4) '(2 3 4) '(3 4)) ⇒ (3 4) -- Function: -min (list) Return the smallest value from LIST of numbers or markers. (-min '(0)) ⇒ 0 (-min '(3 2 1)) ⇒ 1 (-min '(1 2 3)) ⇒ 1 -- Function: -min-by (comparator list) Take a comparison function COMPARATOR and a LIST and return the least element of the list by the comparison function. See also combinator ‘-on’ (*note -on::) which can transform the values before comparing them. (-min-by '> '(4 3 6 1)) ⇒ 1 (--min-by (> (car it) (car other)) '((1 2 3) (2) (3 2))) ⇒ (1 2 3) (--min-by (> (length it) (length other)) '((1 2 3) (2) (3 2))) ⇒ (2) -- Function: -max (list) Return the largest value from LIST of numbers or markers. (-max '(0)) ⇒ 0 (-max '(3 2 1)) ⇒ 3 (-max '(1 2 3)) ⇒ 3 -- Function: -max-by (comparator list) Take a comparison function COMPARATOR and a LIST and return the greatest element of the list by the comparison function. See also combinator ‘-on’ (*note -on::) which can transform the values before comparing them. (-max-by '> '(4 3 6 1)) ⇒ 6 (--max-by (> (car it) (car other)) '((1 2 3) (2) (3 2))) ⇒ (3 2) (--max-by (> (length it) (length other)) '((1 2 3) (2) (3 2))) ⇒ (1 2 3) -- Function: -frequencies (list) Count the occurrences of each distinct element of LIST. Return an alist of (ELEMENT . N), where each ELEMENT occurs N times in LIST. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. See also ‘-count’ (*note -count::) and ‘-group-by’ (*note -group-by::). (-frequencies ()) ⇒ () (-frequencies '(1 2 3 1 2 1)) ⇒ ((1 . 3) (2 . 2) (3 . 1)) (let ((-compare-fn #'string=)) (-frequencies '(a "a"))) ⇒ ((a . 2))  File: dash.info, Node: Unfolding, Next: Predicates, Prev: Reductions, Up: Functions 2.5 Unfolding ============= Operations dual to reductions, building lists from a seed value rather than consuming a list to produce a single value. -- Function: -iterate (fun init n) Return a list of iterated applications of FUN to INIT. This means a list of the form: (INIT (FUN INIT) (FUN (FUN INIT)) ...) N is the length of the returned list. (-iterate #'1+ 1 10) ⇒ (1 2 3 4 5 6 7 8 9 10) (-iterate (lambda (x) (+ x x)) 2 5) ⇒ (2 4 8 16 32) (--iterate (* it it) 2 5) ⇒ (2 4 16 256 65536) -- Function: -unfold (fun seed) Build a list from SEED using FUN. This is "dual" operation to ‘-reduce-r’ (*note -reduce-r::): while -reduce-r consumes a list to produce a single value, ‘-unfold’ (*note -unfold::) takes a seed value and builds a (potentially infinite!) list. FUN should return ‘nil’ to stop the generating process, or a cons (A . B), where A will be prepended to the result and B is the new seed. (-unfold (lambda (x) (unless (= x 0) (cons x (1- x)))) 10) ⇒ (10 9 8 7 6 5 4 3 2 1) (--unfold (when it (cons it (cdr it))) '(1 2 3 4)) ⇒ ((1 2 3 4) (2 3 4) (3 4) (4)) (--unfold (when it (cons it (butlast it))) '(1 2 3 4)) ⇒ ((1 2 3 4) (1 2 3) (1 2) (1)) -- Function: -repeat (n x) Return a new list of length N with each element being X. Return ‘nil’ if N is less than 1. (-repeat 3 :a) ⇒ (:a :a :a) (-repeat 1 :a) ⇒ (:a) (-repeat 0 :a) ⇒ () -- Function: -cycle (list) Return an infinite circular copy of LIST. The returned list cycles through the elements of LIST and repeats from the beginning. (-take 5 (-cycle '(1 2 3))) ⇒ (1 2 3 1 2) (-take 7 (-cycle '(1 "and" 3))) ⇒ (1 "and" 3 1 "and" 3 1) (-zip-lists (-cycle '(3)) '(1 2)) ⇒ ((3 1) (3 2))  File: dash.info, Node: Predicates, Next: Partitioning, Prev: Unfolding, Up: Functions 2.6 Predicates ============== Reductions of one or more lists to a boolean value. -- Function: -some (pred list) Return (PRED x) for the first LIST item where (PRED x) is non-‘nil’, else ‘nil’. Alias: ‘-any’. This function’s anaphoric counterpart is ‘--some’. (-some #'stringp '(1 "2" 3)) ⇒ t (--some (string-match-p "x" it) '("foo" "axe" "xor")) ⇒ 1 (--some (= it-index 3) '(0 1 2)) ⇒ nil -- Function: -every (pred list) Return non-‘nil’ if PRED returns non-‘nil’ for all items in LIST. If so, return the last such result of PRED. Otherwise, once an item is reached for which PRED returns ‘nil’, return ‘nil’ without calling PRED on any further LIST elements. This function is like ‘-every-p’, but on success returns the last non-‘nil’ result of PRED instead of just ‘t’. This function’s anaphoric counterpart is ‘--every’. (-every #'numberp '(1 2 3)) ⇒ t (--every (string-match-p "x" it) '("axe" "xor")) ⇒ 0 (--every (= it it-index) '(0 1 3)) ⇒ nil -- Function: -any? (pred list) Return ‘t’ if (PRED X) is non-‘nil’ for any X in LIST, else ‘nil’. Alias: ‘-any-p’, ‘-some?’, ‘-some-p’ (-any? #'numberp '(nil 0 t)) ⇒ t (-any? #'numberp '(nil t t)) ⇒ nil (-any? #'null '(1 3 5)) ⇒ nil -- Function: -all? (pred list) Return ‘t’ if (PRED X) is non-‘nil’ for all X in LIST, else ‘nil’. In the latter case, stop after the first X for which (PRED X) is ‘nil’, without calling PRED on any subsequent elements of LIST. The similar function ‘-every’ (*note -every::) is more widely useful, since it returns the last non-‘nil’ result of PRED instead of just ‘t’ on success. Alias: ‘-all-p’, ‘-every-p’, ‘-every?’. This function’s anaphoric counterpart is ‘--all?’. (-all? #'numberp '(1 2 3)) ⇒ t (-all? #'numberp '(2 t 6)) ⇒ nil (--all? (= 0 (% it 2)) '(2 4 6)) ⇒ t -- Function: -none? (pred list) Return ‘t’ if (PRED X) is ‘nil’ for all X in LIST, else ‘nil’. Alias: ‘-none-p’ (-none? 'even? '(1 2 3)) ⇒ nil (-none? 'even? '(1 3 5)) ⇒ t (--none? (= 0 (% it 2)) '(1 2 3)) ⇒ nil -- Function: -only-some? (pred list) Return ‘t’ if different LIST items both satisfy and do not satisfy PRED. That is, if PRED returns both ‘nil’ for at least one item, and non-‘nil’ for at least one other item in LIST. Return ‘nil’ if all items satisfy the predicate or none of them do. Alias: ‘-only-some-p’ (-only-some? 'even? '(1 2 3)) ⇒ t (-only-some? 'even? '(1 3 5)) ⇒ nil (-only-some? 'even? '(2 4 6)) ⇒ nil -- Function: -contains? (list element) Return non-‘nil’ if LIST contains ELEMENT. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. As with ‘member’, the return value is actually the tail of LIST whose car is ELEMENT. Alias: ‘-contains-p’. (-contains? '(1 2 3) 1) ⇒ (1 2 3) (-contains? '(1 2 3) 2) ⇒ (2 3) (-contains? '(1 2 3) 4) ⇒ () -- Function: -is-prefix? (prefix list) Return non-‘nil’ if PREFIX is a prefix of LIST. Alias: ‘-is-prefix-p’. (-is-prefix? '(1 2 3) '(1 2 3 4 5)) ⇒ t (-is-prefix? '(1 2 3 4 5) '(1 2 3)) ⇒ nil (-is-prefix? '(1 3) '(1 2 3 4 5)) ⇒ nil -- Function: -is-suffix? (suffix list) Return non-‘nil’ if SUFFIX is a suffix of LIST. Alias: ‘-is-suffix-p’. (-is-suffix? '(3 4 5) '(1 2 3 4 5)) ⇒ t (-is-suffix? '(1 2 3 4 5) '(3 4 5)) ⇒ nil (-is-suffix? '(3 5) '(1 2 3 4 5)) ⇒ nil -- Function: -is-infix? (infix list) Return non-‘nil’ if INFIX is infix of LIST. This operation runs in O(n^2) time Alias: ‘-is-infix-p’ (-is-infix? '(1 2 3) '(1 2 3 4 5)) ⇒ t (-is-infix? '(2 3 4) '(1 2 3 4 5)) ⇒ t (-is-infix? '(3 4 5) '(1 2 3 4 5)) ⇒ t -- Function: -cons-pair? (obj) Return non-‘nil’ if OBJ is a true cons pair. That is, a cons (A . B) where B is not a list. Alias: ‘-cons-pair-p’. (-cons-pair? '(1 . 2)) ⇒ t (-cons-pair? '(1 2)) ⇒ nil (-cons-pair? '(1)) ⇒ nil  File: dash.info, Node: Partitioning, Next: Indexing, Prev: Predicates, Up: Functions 2.7 Partitioning ================ Functions partitioning the input list into a list of lists. -- Function: -split-at (n list) Split LIST into two sublists after the Nth element. The result is a list of two elements (TAKE DROP) where TAKE is a new list of the first N elements of LIST, and DROP is the remaining elements of LIST (not a copy). TAKE and DROP are like the results of ‘-take’ (*note -take::) and ‘-drop’ (*note -drop::), respectively, but the split is done in a single list traversal. (-split-at 3 '(1 2 3 4 5)) ⇒ ((1 2 3) (4 5)) (-split-at 17 '(1 2 3 4 5)) ⇒ ((1 2 3 4 5) nil) (-split-at 0 '(1 2 3 4 5)) ⇒ (nil (1 2 3 4 5)) -- Function: -split-with (pred list) Split LIST into a prefix satisfying PRED, and the rest. The first sublist is the prefix of LIST with successive elements satisfying PRED, and the second sublist is the remaining elements that do not. The result is like performing ((-take-while PRED LIST) (-drop-while PRED LIST)) but in no more than a single pass through LIST. (-split-with 'even? '(1 2 3 4)) ⇒ (nil (1 2 3 4)) (-split-with 'even? '(2 4 5 6)) ⇒ ((2 4) (5 6)) (--split-with (< it 4) '(1 2 3 4 3 2 1)) ⇒ ((1 2 3) (4 3 2 1)) -- Macro: -split-on (item list) Split the LIST each time ITEM is found. Unlike ‘-partition-by’ (*note -partition-by::), the ITEM is discarded from the results. Empty lists are also removed from the result. Comparison is done by ‘equal’. See also ‘-split-when’ (*note -split-when::) (-split-on '| '(Nil | Leaf a | Node [Tree a])) ⇒ ((Nil) (Leaf a) (Node [Tree a])) (-split-on :endgroup '("a" "b" :endgroup "c" :endgroup "d" "e")) ⇒ (("a" "b") ("c") ("d" "e")) (-split-on :endgroup '("a" "b" :endgroup :endgroup "d" "e")) ⇒ (("a" "b") ("d" "e")) -- Function: -split-when (fn list) Split the LIST on each element where FN returns non-‘nil’. Unlike ‘-partition-by’ (*note -partition-by::), the "matched" element is discarded from the results. Empty lists are also removed from the result. This function can be thought of as a generalization of ‘split-string’. (-split-when 'even? '(1 2 3 4 5 6)) ⇒ ((1) (3) (5)) (-split-when 'even? '(1 2 3 4 6 8 9)) ⇒ ((1) (3) (9)) (--split-when (memq it '(&optional &rest)) '(a b &optional c d &rest args)) ⇒ ((a b) (c d) (args)) -- Function: -separate (pred list) Split LIST into two sublists based on whether items satisfy PRED. The result is like performing ((-filter PRED LIST) (-remove PRED LIST)) but in a single pass through LIST. (-separate (lambda (num) (= 0 (% num 2))) '(1 2 3 4 5 6 7)) ⇒ ((2 4 6) (1 3 5 7)) (--separate (< it 5) '(3 7 5 9 3 2 1 4 6)) ⇒ ((3 3 2 1 4) (7 5 9 6)) (-separate 'cdr '((1 2) (1) (1 2 3) (4))) ⇒ (((1 2) (1 2 3)) ((1) (4))) -- Function: -partition (n list) Return a new list with the items in LIST grouped into N-sized sublists. If there are not enough items to make the last group N-sized, those items are discarded. (-partition 2 '(1 2 3 4 5 6)) ⇒ ((1 2) (3 4) (5 6)) (-partition 2 '(1 2 3 4 5 6 7)) ⇒ ((1 2) (3 4) (5 6)) (-partition 3 '(1 2 3 4 5 6 7)) ⇒ ((1 2 3) (4 5 6)) -- Function: -partition-all (n list) Return a new list with the items in LIST grouped into N-sized sublists. The last group may contain less than N items. (-partition-all 2 '(1 2 3 4 5 6)) ⇒ ((1 2) (3 4) (5 6)) (-partition-all 2 '(1 2 3 4 5 6 7)) ⇒ ((1 2) (3 4) (5 6) (7)) (-partition-all 3 '(1 2 3 4 5 6 7)) ⇒ ((1 2 3) (4 5 6) (7)) -- Function: -partition-in-steps (n step list) Partition LIST into sublists of length N that are STEP items apart. Like ‘-partition-all-in-steps’ (*note -partition-all-in-steps::), but if there are not enough items to make the last group N-sized, those items are discarded. (-partition-in-steps 2 1 '(1 2 3 4)) ⇒ ((1 2) (2 3) (3 4)) (-partition-in-steps 3 2 '(1 2 3 4)) ⇒ ((1 2 3)) (-partition-in-steps 3 2 '(1 2 3 4 5)) ⇒ ((1 2 3) (3 4 5)) -- Function: -partition-all-in-steps (n step list) Partition LIST into sublists of length N that are STEP items apart. Adjacent groups may overlap if N exceeds the STEP stride. Trailing groups may contain less than N items. (-partition-all-in-steps 2 1 '(1 2 3 4)) ⇒ ((1 2) (2 3) (3 4) (4)) (-partition-all-in-steps 3 2 '(1 2 3 4)) ⇒ ((1 2 3) (3 4)) (-partition-all-in-steps 3 2 '(1 2 3 4 5)) ⇒ ((1 2 3) (3 4 5) (5)) -- Function: -partition-by (fn list) Apply FN to each item in LIST, splitting it each time FN returns a new value. (-partition-by 'even? ()) ⇒ () (-partition-by 'even? '(1 1 2 2 2 3 4 6 8)) ⇒ ((1 1) (2 2 2) (3) (4 6 8)) (--partition-by (< it 3) '(1 2 3 4 3 2 1)) ⇒ ((1 2) (3 4 3) (2 1)) -- Function: -partition-by-header (fn list) Apply FN to the first item in LIST. That is the header value. Apply FN to each item in LIST, splitting it each time FN returns the header value, but only after seeing at least one other value (the body). (--partition-by-header (= it 1) '(1 2 3 1 2 1 2 3 4)) ⇒ ((1 2 3) (1 2) (1 2 3 4)) (--partition-by-header (> it 0) '(1 2 0 1 0 1 2 3 0)) ⇒ ((1 2 0) (1 0) (1 2 3 0)) (-partition-by-header 'even? '(2 1 1 1 4 1 3 5 6 6 1)) ⇒ ((2 1 1 1) (4 1 3 5) (6 6 1)) -- Function: -partition-after-pred (pred list) Partition LIST after each element for which PRED returns non-‘nil’. This function’s anaphoric counterpart is ‘--partition-after-pred’. (-partition-after-pred #'booleanp ()) ⇒ () (-partition-after-pred #'booleanp '(t t)) ⇒ ((t) (t)) (-partition-after-pred #'booleanp '(0 0 t t 0 t)) ⇒ ((0 0 t) (t) (0 t)) -- Function: -partition-before-pred (pred list) Partition directly before each time PRED is true on an element of LIST. (-partition-before-pred #'booleanp ()) ⇒ () (-partition-before-pred #'booleanp '(0 t)) ⇒ ((0) (t)) (-partition-before-pred #'booleanp '(0 0 t 0 t t)) ⇒ ((0 0) (t 0) (t) (t)) -- Function: -partition-before-item (item list) Partition directly before each time ITEM appears in LIST. (-partition-before-item 3 ()) ⇒ () (-partition-before-item 3 '(1)) ⇒ ((1)) (-partition-before-item 3 '(3)) ⇒ ((3)) -- Function: -partition-after-item (item list) Partition directly after each time ITEM appears in LIST. (-partition-after-item 3 ()) ⇒ () (-partition-after-item 3 '(1)) ⇒ ((1)) (-partition-after-item 3 '(3)) ⇒ ((3)) -- Function: -group-by (fn list) Separate LIST into an alist whose keys are FN applied to the elements of LIST. Keys are compared by ‘equal’. (-group-by 'even? ()) ⇒ () (-group-by 'even? '(1 1 2 2 2 3 4 6 8)) ⇒ ((nil 1 1 3) (t 2 2 2 4 6 8)) (--group-by (car (split-string it "/")) '("a/b" "c/d" "a/e")) ⇒ (("a" "a/b" "a/e") ("c" "c/d"))  File: dash.info, Node: Indexing, Next: Set operations, Prev: Partitioning, Up: Functions 2.8 Indexing ============ Functions retrieving or sorting based on list indices and related predicates. -- Function: -elem-index (elem list) Return the first index of ELEM in LIST. That is, the index within LIST of the first element that is ‘equal’ to ELEM. Return ‘nil’ if there is no such element. See also: ‘-find-index’ (*note -find-index::). (-elem-index 2 '(6 7 8 3 4)) ⇒ nil (-elem-index "bar" '("foo" "bar" "baz")) ⇒ 1 (-elem-index '(1 2) '((3) (5 6) (1 2) nil)) ⇒ 2 -- Function: -elem-indices (elem list) Return the list of indices at which ELEM appears in LIST. That is, the indices of all elements of LIST ‘equal’ to ELEM, in the same ascending order as they appear in LIST. (-elem-indices 2 '(6 7 8 3 4 1)) ⇒ () (-elem-indices "bar" '("foo" "bar" "baz")) ⇒ (1) (-elem-indices '(1 2) '((3) (1 2) (5 6) (1 2) nil)) ⇒ (1 3) -- Function: -find-index (pred list) Return the index of the first item satisfying PRED in LIST. Return ‘nil’ if no such item is found. PRED is called with one argument, the current list element, until it returns non-‘nil’, at which point the search terminates. This function’s anaphoric counterpart is ‘--find-index’. See also: ‘-first’ (*note -first::), ‘-find-last-index’ (*note -find-last-index::). (-find-index #'numberp '(a b c)) ⇒ nil (-find-index #'natnump '(1 0 -1)) ⇒ 0 (--find-index (> it 5) '(2 4 1 6 3 3 5 8)) ⇒ 3 -- Function: -find-last-index (pred list) Return the index of the last item satisfying PRED in LIST. Return ‘nil’ if no such item is found. Predicate PRED is called with one argument each time, namely the current list element. This function’s anaphoric counterpart is ‘--find-last-index’. See also: ‘-last’ (*note -last::), ‘-find-index’ (*note -find-index::). (-find-last-index #'numberp '(a b c)) ⇒ nil (--find-last-index (> it 5) '(2 7 1 6 3 8 5 2)) ⇒ 5 (-find-last-index (-partial #'string< 'a) '(c b a)) ⇒ 1 -- Function: -find-indices (pred list) Return the list of indices in LIST satisfying PRED. Each element of LIST in turn is passed to PRED. If the result is non-‘nil’, the index of that element in LIST is included in the result. The returned indices are in ascending order, i.e., in the same order as they appear in LIST. This function’s anaphoric counterpart is ‘--find-indices’. See also: ‘-find-index’ (*note -find-index::), ‘-elem-indices’ (*note -elem-indices::). (-find-indices #'numberp '(a b c)) ⇒ () (-find-indices #'numberp '(8 1 d 2 b c a 3)) ⇒ (0 1 3 7) (--find-indices (> it 5) '(2 4 1 6 3 3 5 8)) ⇒ (3 7) -- Function: -grade-up (comparator list) Grade elements of LIST using COMPARATOR relation. This yields a permutation vector such that applying this permutation to LIST sorts it in ascending order. (-grade-up #'< '(3 1 4 2 1 3 3)) ⇒ (1 4 3 0 5 6 2) (let ((l '(3 1 4 2 1 3 3))) (-select-by-indices (-grade-up #'< l) l)) ⇒ (1 1 2 3 3 3 4) -- Function: -grade-down (comparator list) Grade elements of LIST using COMPARATOR relation. This yields a permutation vector such that applying this permutation to LIST sorts it in descending order. (-grade-down #'< '(3 1 4 2 1 3 3)) ⇒ (2 0 5 6 3 1 4) (let ((l '(3 1 4 2 1 3 3))) (-select-by-indices (-grade-down #'< l) l)) ⇒ (4 3 3 3 2 1 1)  File: dash.info, Node: Set operations, Next: Other list operations, Prev: Indexing, Up: Functions 2.9 Set operations ================== Operations pretending lists are sets. -- Function: -union (list1 list2) Return a new list of distinct elements appearing in either LIST1 or LIST2. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. (-union '(1 2 3) '(3 4 5)) ⇒ (1 2 3 4 5) (-union '(1 2 2 4) ()) ⇒ (1 2 4) (-union '(1 1 2 2) '(4 4 3 2 1)) ⇒ (1 2 4 3) -- Function: -difference (list1 list2) Return a new list with the distinct members of LIST1 that are not in LIST2. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. (-difference () ()) ⇒ () (-difference '(1 2 3) '(4 5 6)) ⇒ (1 2 3) (-difference '(1 2 3 4) '(3 4 5 6)) ⇒ (1 2) -- Function: -intersection (list1 list2) Return a new list of distinct elements appearing in both LIST1 and LIST2. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. (-intersection () ()) ⇒ () (-intersection '(1 2 3) '(4 5 6)) ⇒ () (-intersection '(1 2 2 3) '(4 3 3 2)) ⇒ (2 3) -- Function: -powerset (list) Return the power set of LIST. (-powerset ()) ⇒ (nil) (-powerset '(x y)) ⇒ ((x y) (x) (y) nil) (-powerset '(x y z)) ⇒ ((x y z) (x y) (x z) (x) (y z) (y) (z) nil) -- Function: -permutations (list) Return the distinct permutations of LIST. Duplicate elements of LIST are determined by ‘equal’, or by ‘-compare-fn’ if that is non-‘nil’. (-permutations ()) ⇒ (nil) (-permutations '(a a b)) ⇒ ((a a b) (a b a) (b a a)) (-permutations '(a b c)) ⇒ ((a b c) (a c b) (b a c) (b c a) (c a b) (c b a)) -- Function: -distinct (list) Return a copy of LIST with all duplicate elements removed. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. Alias: ‘-uniq’. (-distinct ()) ⇒ () (-distinct '(1 1 2 3 3)) ⇒ (1 2 3) (-distinct '(t t t)) ⇒ (t) -- Function: -same-items? (list1 list2) Return non-‘nil’ if LIST1 and LIST2 have the same distinct elements. The order of the elements in the lists does not matter. The lists may be of different lengths, i.e., contain duplicate elements. The test for equality is done with ‘equal’, or with ‘-compare-fn’ if that is non-‘nil’. Alias: ‘-same-items-p’. (-same-items? '(1 2 3) '(1 2 3)) ⇒ t (-same-items? '(1 1 2 3) '(3 3 2 1)) ⇒ t (-same-items? '(1 2 3) '(1 2 3 4)) ⇒ nil  File: dash.info, Node: Other list operations, Next: Tree operations, Prev: Set operations, Up: Functions 2.10 Other list operations ========================== Other list functions not fit to be classified elsewhere. -- Function: -rotate (n list) Rotate LIST N places to the right (left if N is negative). The time complexity is O(n). (-rotate 3 '(1 2 3 4 5 6 7)) ⇒ (5 6 7 1 2 3 4) (-rotate -3 '(1 2 3 4 5 6 7)) ⇒ (4 5 6 7 1 2 3) (-rotate 16 '(1 2 3 4 5 6 7)) ⇒ (6 7 1 2 3 4 5) -- Function: -cons* (&rest args) Make a new list from the elements of ARGS. The last 2 elements of ARGS are used as the final cons of the result, so if the final element of ARGS is not a list, the result is a dotted list. With no ARGS, return ‘nil’. (-cons* 1 2) ⇒ (1 . 2) (-cons* 1 2 3) ⇒ (1 2 . 3) (-cons* 1) ⇒ 1 -- Function: -snoc (list elem &rest elements) Append ELEM to the end of the list. This is like ‘cons’, but operates on the end of list. If any ELEMENTS are given, append them to the list as well. (-snoc '(1 2 3) 4) ⇒ (1 2 3 4) (-snoc '(1 2 3) 4 5 6) ⇒ (1 2 3 4 5 6) (-snoc '(1 2 3) '(4 5 6)) ⇒ (1 2 3 (4 5 6)) -- Function: -interpose (sep list) Return a new list of all elements in LIST separated by SEP. (-interpose "-" ()) ⇒ () (-interpose "-" '("a")) ⇒ ("a") (-interpose "-" '("a" "b" "c")) ⇒ ("a" "-" "b" "-" "c") -- Function: -interleave (&rest lists) Return a new list of the first item in each list, then the second etc. (-interleave '(1 2) '("a" "b")) ⇒ (1 "a" 2 "b") (-interleave '(1 2) '("a" "b") '("A" "B")) ⇒ (1 "a" "A" 2 "b" "B") (-interleave '(1 2 3) '("a" "b")) ⇒ (1 "a" 2 "b") -- Function: -iota (count &optional start step) Return a list containing COUNT numbers. Starts from START and adds STEP each time. The default START is zero, the default STEP is 1. This function takes its name from the corresponding primitive in the APL language. (-iota 6) ⇒ (0 1 2 3 4 5) (-iota 4 2.5 -2) ⇒ (2.5 0.5 -1.5 -3.5) (-iota -1) error→ Wrong type argument: natnump, -1 -- Function: -zip-with (fn list1 list2) Zip LIST1 and LIST2 into a new list using the function FN. That is, apply FN pairwise taking as first argument the next element of LIST1 and as second argument the next element of LIST2 at the corresponding position. The result is as long as the shorter list. This function’s anaphoric counterpart is ‘--zip-with’. For other zips, see also ‘-zip-lists’ (*note -zip-lists::) and ‘-zip-fill’ (*note -zip-fill::). (-zip-with #'+ '(1 2 3 4) '(5 6 7)) ⇒ (6 8 10) (-zip-with #'cons '(1 2 3) '(4 5 6 7)) ⇒ ((1 . 4) (2 . 5) (3 . 6)) (--zip-with (format "%s & %s" it other) '(Batman Jekyll) '(Robin Hyde)) ⇒ ("Batman & Robin" "Jekyll & Hyde") -- Function: -zip-pair (list1 list2) Zip LIST1 and LIST2 together. Make a pair with the head of each list, followed by a pair with the second element of each list, and so on. The number of pairs returned is equal to the length of the shorter input list. See also: ‘-zip-lists’ (*note -zip-lists::). (-zip-pair '(1 2 3 4) '(5 6 7)) ⇒ ((1 . 5) (2 . 6) (3 . 7)) (-zip-pair '(1 2 3) '(4 5 6)) ⇒ ((1 . 4) (2 . 5) (3 . 6)) (-zip-pair '(1 2) '(3)) ⇒ ((1 . 3)) -- Function: -zip-lists (&rest lists) Zip LISTS together. Group the head of each list, followed by the second element of each list, and so on. The number of returned groupings is equal to the length of the shortest input list, and the length of each grouping is equal to the number of input LISTS. The return value is always a list of proper lists, in contrast to ‘-zip’ (*note -zip::) which returns a list of dotted pairs when only two input LISTS are provided. See also: ‘-zip-pair’ (*note -zip-pair::). (-zip-lists '(1 2 3) '(4 5 6)) ⇒ ((1 4) (2 5) (3 6)) (-zip-lists '(1 2 3) '(4 5 6 7)) ⇒ ((1 4) (2 5) (3 6)) (-zip-lists '(1 2) '(3 4 5) '(6)) ⇒ ((1 3 6)) -- Function: -zip-lists-fill (fill-value &rest lists) Zip LISTS together, padding shorter lists with FILL-VALUE. This is like ‘-zip-lists’ (*note -zip-lists::) (which see), except it retains all elements at positions beyond the end of the shortest list. The number of returned groupings is equal to the length of the longest input list, and the length of each grouping is equal to the number of input LISTS. (-zip-lists-fill 0 '(1 2) '(3 4 5) '(6)) ⇒ ((1 3 6) (2 4 0) (0 5 0)) (-zip-lists-fill 0 '(1 2) '(3 4) '(5 6)) ⇒ ((1 3 5) (2 4 6)) (-zip-lists-fill 0 '(1 2 3) nil) ⇒ ((1 0) (2 0) (3 0)) -- Function: -zip (&rest lists) Zip LISTS together. Group the head of each list, followed by the second element of each list, and so on. The number of returned groupings is equal to the length of the shortest input list, and the number of items in each grouping is equal to the number of input LISTS. If only two LISTS are provided as arguments, return the groupings as a list of dotted pairs. Otherwise, return the groupings as a list of proper lists. Since the return value changes form depending on the number of arguments, it is generally recommended to use ‘-zip-lists’ (*note -zip-lists::) instead, or ‘-zip-pair’ (*note -zip-pair::) if a list of dotted pairs is desired. See also: ‘-unzip’ (*note -unzip::). (-zip '(1 2 3 4) '(5 6 7) '(8 9)) ⇒ ((1 5 8) (2 6 9)) (-zip '(1 2 3) '(4 5 6) '(7 8 9)) ⇒ ((1 4 7) (2 5 8) (3 6 9)) (-zip '(1 2 3)) ⇒ ((1) (2) (3)) -- Function: -zip-fill (fill-value &rest lists) Zip LISTS together, padding shorter lists with FILL-VALUE. This is like ‘-zip’ (*note -zip::) (which see), except it retains all elements at positions beyond the end of the shortest list. The number of returned groupings is equal to the length of the longest input list, and the length of each grouping is equal to the number of input LISTS. Since the return value changes form depending on the number of arguments, it is generally recommended to use ‘-zip-lists-fill’ (*note -zip-lists-fill::) instead, unless a list of dotted pairs is explicitly desired. (-zip-fill 0 '(1 2 3) '(4 5)) ⇒ ((1 . 4) (2 . 5) (3 . 0)) (-zip-fill 0 () '(1 2 3)) ⇒ ((0 . 1) (0 . 2) (0 . 3)) (-zip-fill 0 '(1 2) '(3 4) '(5 6)) ⇒ ((1 3 5) (2 4 6)) -- Function: -unzip-lists (lists) Unzip LISTS. This works just like ‘-zip-lists’ (*note -zip-lists::) (which see), but takes a list of lists instead of a variable number of arguments, such that (-unzip-lists (-zip-lists ARGS...)) is identity (given that the lists comprising ARGS are of the same length). (-unzip-lists (-zip-lists '(1 2) '(3 4) '(5 6))) ⇒ ((1 2) (3 4) (5 6)) (-unzip-lists '((1 2 3) (4 5) (6 7) (8 9))) ⇒ ((1 4 6 8) (2 5 7 9)) (-unzip-lists '((1 2 3) (4 5 6))) ⇒ ((1 4) (2 5) (3 6)) -- Function: -unzip (lists) Unzip LISTS. This works just like ‘-zip’ (*note -zip::) (which see), but takes a list of lists instead of a variable number of arguments, such that (-unzip (-zip L1 L2 L3 ...)) is identity (given that the lists are of the same length, and that ‘-zip’ (*note -zip::) is not called with two arguments, because of the caveat described in its docstring). Note in particular that calling ‘-unzip’ (*note -unzip::) on a list of two lists will return a list of dotted pairs. Since the return value changes form depending on the number of LISTS, it is generally recommended to use ‘-unzip-lists’ (*note -unzip-lists::) instead. (-unzip (-zip '(1 2) '(3 4) '(5 6))) ⇒ ((1 . 2) (3 . 4) (5 . 6)) (-unzip '((1 2 3) (4 5 6))) ⇒ ((1 . 4) (2 . 5) (3 . 6)) (-unzip '((1 2 3) (4 5) (6 7) (8 9))) ⇒ ((1 4 6 8) (2 5 7 9)) -- Function: -pad (fill-value &rest lists) Pad each of LISTS with FILL-VALUE until they all have equal lengths. Ensure all LISTS are as long as the longest one by repeatedly appending FILL-VALUE to the shorter lists, and return the resulting LISTS. (-pad 0 ()) ⇒ (nil) (-pad 0 '(1 2) '(3 4)) ⇒ ((1 2) (3 4)) (-pad 0 '(1 2) '(3 4 5 6) '(7 8 9)) ⇒ ((1 2 0 0) (3 4 5 6) (7 8 9 0)) -- Function: -table (fn &rest lists) Compute outer product of LISTS using function FN. The function FN should have the same arity as the number of supplied lists. The outer product is computed by applying fn to all possible combinations created by taking one element from each list in order. The dimension of the result is (length lists). See also: ‘-table-flat’ (*note -table-flat::) (-table '* '(1 2 3) '(1 2 3)) ⇒ ((1 2 3) (2 4 6) (3 6 9)) (-table (lambda (a b) (-sum (-zip-with '* a b))) '((1 2) (3 4)) '((1 3) (2 4))) ⇒ ((7 15) (10 22)) (apply '-table 'list (-repeat 3 '(1 2))) ⇒ ((((1 1 1) (2 1 1)) ((1 2 1) (2 2 1))) (((1 1 2) (2 1 2)) ((1 2 2) (2 2 2)))) -- Function: -table-flat (fn &rest lists) Compute flat outer product of LISTS using function FN. The function FN should have the same arity as the number of supplied lists. The outer product is computed by applying fn to all possible combinations created by taking one element from each list in order. The results are flattened, ignoring the tensor structure of the result. This is equivalent to calling: (-flatten-n (1- (length lists)) (apply ’-table fn lists)) but the implementation here is much more efficient. See also: ‘-flatten-n’ (*note -flatten-n::), ‘-table’ (*note -table::) (-table-flat 'list '(1 2 3) '(a b c)) ⇒ ((1 a) (2 a) (3 a) (1 b) (2 b) (3 b) (1 c) (2 c) (3 c)) (-table-flat '* '(1 2 3) '(1 2 3)) ⇒ (1 2 3 2 4 6 3 6 9) (apply '-table-flat 'list (-repeat 3 '(1 2))) ⇒ ((1 1 1) (2 1 1) (1 2 1) (2 2 1) (1 1 2) (2 1 2) (1 2 2) (2 2 2)) -- Function: -first (pred list) Return the first item in LIST for which PRED returns non-‘nil’. Return ‘nil’ if no such element is found. To get the first item in the list no questions asked, use ‘-first-item’ (*note -first-item::). Alias: ‘-find’. This function’s anaphoric counterpart is ‘--first’. (-first #'natnump '(-1 0 1)) ⇒ 0 (-first #'null '(1 2 3)) ⇒ nil (--first (> it 2) '(1 2 3)) ⇒ 3 -- Function: -last (pred list) Return the last x in LIST where (PRED x) is non-‘nil’, else ‘nil’. (-last 'even? '(1 2 3 4 5 6 3 3 3)) ⇒ 6 (-last 'even? '(1 3 7 5 9)) ⇒ nil (--last (> (length it) 3) '("a" "looong" "word" "and" "short" "one")) ⇒ "short" -- Function: -first-item (list) Return the first item of LIST, or ‘nil’ on an empty list. See also: ‘-second-item’ (*note -second-item::), ‘-last-item’ (*note -last-item::), etc. (-first-item ()) ⇒ () (-first-item '(1 2 3 4 5)) ⇒ 1 (let ((list (list 1 2 3))) (setf (-first-item list) 5) list) ⇒ (5 2 3) -- Function: -second-item (list) Return the second item of LIST, or ‘nil’ if LIST is too short. See also: ‘-first-item’ (*note -first-item::), ‘-third-item’ (*note -third-item::), etc. (-second-item ()) ⇒ () (-second-item '(1 2 3 4 5)) ⇒ 2 (let ((list (list 1 2))) (setf (-second-item list) 5) list) ⇒ (1 5) -- Function: -third-item (list) Return the third item of LIST, or ‘nil’ if LIST is too short. See also: ‘-second-item’ (*note -second-item::), ‘-fourth-item’ (*note -fourth-item::), etc. (-third-item ()) ⇒ () (-third-item '(1 2)) ⇒ () (-third-item '(1 2 3 4 5)) ⇒ 3 -- Function: -fourth-item (list) Return the fourth item of LIST, or ‘nil’ if LIST is too short. See also: ‘-third-item’ (*note -third-item::), ‘-fifth-item’ (*note -fifth-item::), etc. (-fourth-item ()) ⇒ () (-fourth-item '(1 2 3)) ⇒ () (-fourth-item '(1 2 3 4 5)) ⇒ 4 -- Function: -fifth-item (list) Return the fifth item of LIST, or ‘nil’ if LIST is too short. See also: ‘-fourth-item’ (*note -fourth-item::), ‘-last-item’ (*note -last-item::), etc. (-fifth-item ()) ⇒ () (-fifth-item '(1 2 3 4)) ⇒ () (-fifth-item '(1 2 3 4 5)) ⇒ 5 -- Function: -last-item (list) Return the last item of LIST, or ‘nil’ on an empty list. See also: ‘-first-item’ (*note -first-item::), etc. (-last-item ()) ⇒ () (-last-item '(1 2 3 4 5)) ⇒ 5 (let ((list (list 1 2 3))) (setf (-last-item list) 5) list) ⇒ (1 2 5) -- Function: -butlast (list) Return a list of all items in list except for the last. (-butlast '(1 2 3)) ⇒ (1 2) (-butlast '(1 2)) ⇒ (1) (-butlast '(1)) ⇒ nil -- Function: -sort (comparator list) Sort LIST, stably, comparing elements using COMPARATOR. Return the sorted list. LIST is NOT modified by side effects. COMPARATOR is called with two elements of LIST, and should return non-‘nil’ if the first element should sort before the second. (-sort '< '(3 1 2)) ⇒ (1 2 3) (-sort '> '(3 1 2)) ⇒ (3 2 1) (--sort (< it other) '(3 1 2)) ⇒ (1 2 3) -- Function: -list (arg) Ensure ARG is a list. If ARG is already a list, return it as is (not a copy). Otherwise, return a new list with ARG as its only element. Another supported calling convention is (-list &rest ARGS). In this case, if ARG is not a list, a new list with all of ARGS as elements is returned. This use is supported for backward compatibility and is otherwise deprecated. (-list 1) ⇒ (1) (-list ()) ⇒ () (-list '(1 2 3)) ⇒ (1 2 3) -- Function: -fix (fn list) Compute the (least) fixpoint of FN with initial input LIST. FN is called at least once, results are compared with ‘equal’. (-fix (lambda (l) (-non-nil (--mapcat (-split-at (/ (length it) 2) it) l))) '((1 2 3))) ⇒ ((1) (2) (3)) (let ((l '((starwars scifi) (jedi starwars warrior)))) (--fix (-uniq (--mapcat (cons it (cdr (assq it l))) it)) '(jedi book))) ⇒ (jedi starwars warrior scifi book)  File: dash.info, Node: Tree operations, Next: Threading macros, Prev: Other list operations, Up: Functions 2.11 Tree operations ==================== Functions pretending lists are trees. -- Function: -tree-seq (branch children tree) Return a sequence of the nodes in TREE, in depth-first search order. BRANCH is a predicate of one argument that returns non-‘nil’ if the passed argument is a branch, that is, a node that can have children. CHILDREN is a function of one argument that returns the children of the passed branch node. Non-branch nodes are simply copied. (-tree-seq 'listp 'identity '(1 (2 3) 4 (5 (6 7)))) ⇒ ((1 (2 3) 4 (5 (6 7))) 1 (2 3) 2 3 4 (5 (6 7)) 5 (6 7) 6 7) (-tree-seq 'listp 'reverse '(1 (2 3) 4 (5 (6 7)))) ⇒ ((1 (2 3) 4 (5 (6 7))) (5 (6 7)) (6 7) 7 6 5 4 (2 3) 3 2 1) (--tree-seq (vectorp it) (append it nil) [1 [2 3] 4 [5 [6 7]]]) ⇒ ([1 [2 3] 4 [5 [6 7]]] 1 [2 3] 2 3 4 [5 [6 7]] 5 [6 7] 6 7) -- Function: -tree-map (fn tree) Apply FN to each element of TREE while preserving the tree structure. (-tree-map '1+ '(1 (2 3) (4 (5 6) 7))) ⇒ (2 (3 4) (5 (6 7) 8)) (-tree-map '(lambda (x) (cons x (expt 2 x))) '(1 (2 3) 4)) ⇒ ((1 . 2) ((2 . 4) (3 . 8)) (4 . 16)) (--tree-map (length it) '("" ("

" "text" "

") "")) ⇒ (6 (3 4 4) 7) -- Function: -tree-map-nodes (pred fun tree) Call FUN on each node of TREE that satisfies PRED. If PRED returns ‘nil’, continue descending down this node. If PRED returns non-‘nil’, apply FUN to this node and do not descend further. (-tree-map-nodes 'vectorp (lambda (x) (-sum (append x nil))) '(1 [2 3] 4 (5 [6 7] 8))) ⇒ (1 5 4 (5 13 8)) (-tree-map-nodes 'keywordp (lambda (x) (symbol-name x)) '(1 :foo 4 ((5 6 :bar) :baz 8))) ⇒ (1 ":foo" 4 ((5 6 ":bar") ":baz" 8)) (--tree-map-nodes (eq (car-safe it) 'add-mode) (-concat it (list :mode 'emacs-lisp-mode)) '(with-mode emacs-lisp-mode (foo bar) (add-mode a b) (baz (add-mode c d)))) ⇒ (with-mode emacs-lisp-mode (foo bar) (add-mode a b :mode emacs-lisp-mode) (baz (add-mode c d :mode emacs-lisp-mode))) -- Function: -tree-reduce (fn tree) Use FN to reduce elements of list TREE. If elements of TREE are lists themselves, apply the reduction recursively. FN is first applied to first element of the list and second element, then on this result and third element from the list etc. See ‘-reduce-r’ (*note -reduce-r::) for how exactly are lists of zero or one element handled. (-tree-reduce '+ '(1 (2 3) (4 5))) ⇒ 15 (-tree-reduce 'concat '("strings" (" on" " various") ((" levels")))) ⇒ "strings on various levels" (--tree-reduce (cond ((stringp it) (concat it " " acc)) (t (let ((sn (symbol-name it))) (concat "<" sn ">" acc "")))) '(body (p "some words") (div "more" (b "bold") "words"))) ⇒ "

some words

more bold words
" -- Function: -tree-reduce-from (fn init-value tree) Use FN to reduce elements of list TREE. If elements of TREE are lists themselves, apply the reduction recursively. FN is first applied to INIT-VALUE and first element of the list, then on this result and second element from the list etc. The initial value is ignored on cons pairs as they always contain two elements. (-tree-reduce-from '+ 1 '(1 (1 1) ((1)))) ⇒ 8 (--tree-reduce-from (-concat acc (list it)) nil '(1 (2 3 (4 5)) (6 7))) ⇒ ((7 6) ((5 4) 3 2) 1) -- Function: -tree-mapreduce (fn folder tree) Apply FN to each element of TREE, and make a list of the results. If elements of TREE are lists themselves, apply FN recursively to elements of these nested lists. Then reduce the resulting lists using FOLDER and initial value INIT-VALUE. See ‘-reduce-r-from’ (*note -reduce-r-from::). This is the same as calling ‘-tree-reduce’ (*note -tree-reduce::) after ‘-tree-map’ (*note -tree-map::) but is twice as fast as it only traverse the structure once. (-tree-mapreduce 'list 'append '(1 (2 (3 4) (5 6)) (7 (8 9)))) ⇒ (1 2 3 4 5 6 7 8 9) (--tree-mapreduce 1 (+ it acc) '(1 (2 (4 9) (2 1)) (7 (4 3)))) ⇒ 9 (--tree-mapreduce 0 (max acc (1+ it)) '(1 (2 (4 9) (2 1)) (7 (4 3)))) ⇒ 3 -- Function: -tree-mapreduce-from (fn folder init-value tree) Apply FN to each element of TREE, and make a list of the results. If elements of TREE are lists themselves, apply FN recursively to elements of these nested lists. Then reduce the resulting lists using FOLDER and initial value INIT-VALUE. See ‘-reduce-r-from’ (*note -reduce-r-from::). This is the same as calling ‘-tree-reduce-from’ (*note -tree-reduce-from::) after ‘-tree-map’ (*note -tree-map::) but is twice as fast as it only traverse the structure once. (-tree-mapreduce-from 'identity '* 1 '(1 (2 (3 4) (5 6)) (7 (8 9)))) ⇒ 362880 (--tree-mapreduce-from (+ it it) (cons it acc) nil '(1 (2 (4 9) (2 1)) (7 (4 3)))) ⇒ (2 (4 (8 18) (4 2)) (14 (8 6))) (concat "{" (--tree-mapreduce-from (cond ((-cons-pair? it) (concat (symbol-name (car it)) " -> " (symbol-name (cdr it)))) (t (concat (symbol-name it) " : {"))) (concat it (unless (or (equal acc "}") (equal (substring it (1- (length it))) "{")) ", ") acc) "}" '((elisp-mode (foo (bar . booze)) (baz . qux)) (c-mode (foo . bla) (bum . bam))))) ⇒ "{elisp-mode : {foo : {bar -> booze}, baz -> qux}, c-mode : {foo -> bla, bum -> bam}}" -- Function: -clone (list) Create a deep copy of LIST. The new list has the same elements and structure but all cons are replaced with new ones. This is useful when you need to clone a structure such as plist or alist. (let* ((a '(1 2 3)) (b (-clone a))) (nreverse a) b) ⇒ (1 2 3)  File: dash.info, Node: Threading macros, Next: Binding, Prev: Tree operations, Up: Functions 2.12 Threading macros ===================== Macros that conditionally combine sequential forms for brevity or readability. -- Macro: -> (x &optional form &rest more) Thread the expr through the forms. Insert X as the second item in the first form, making a list of it if it is not a list already. If there are more forms, insert the first form as the second item in second form, etc. (-> '(2 3 5)) ⇒ (2 3 5) (-> '(2 3 5) (append '(8 13))) ⇒ (2 3 5 8 13) (-> '(2 3 5) (append '(8 13)) (-slice 1 -1)) ⇒ (3 5 8) -- Macro: ->> (x &optional form &rest more) Thread the expr through the forms. Insert X as the last item in the first form, making a list of it if it is not a list already. If there are more forms, insert the first form as the last item in second form, etc. (->> '(1 2 3) (-map 'square)) ⇒ (1 4 9) (->> '(1 2 3) (-map 'square) (-remove 'even?)) ⇒ (1 9) (->> '(1 2 3) (-map 'square) (-reduce '+)) ⇒ 14 -- Macro: --> (x &rest forms) Starting with the value of X, thread each expression through FORMS. Insert X at the position signified by the symbol ‘it’ in the first form. If there are more forms, insert the first form at the position signified by ‘it’ in in second form, etc. (--> "def" (concat "abc" it "ghi")) ⇒ "abcdefghi" (--> "def" (concat "abc" it "ghi") (upcase it)) ⇒ "ABCDEFGHI" (--> "def" (concat "abc" it "ghi") upcase) ⇒ "ABCDEFGHI" -- Macro: -as-> (value variable &rest forms) Starting with VALUE, thread VARIABLE through FORMS. In the first form, bind VARIABLE to VALUE. In the second form, bind VARIABLE to the result of the first form, and so forth. (-as-> 3 my-var (1+ my-var) (list my-var) (mapcar (lambda (ele) (* 2 ele)) my-var)) ⇒ (8) (-as-> 3 my-var 1+) ⇒ 4 (-as-> 3 my-var) ⇒ 3 -- Macro: -some-> (x &optional form &rest more) When expr is non-‘nil’, thread it through the first form (via ‘->’ (*note ->::)), and when that result is non-‘nil’, through the next form, etc. (-some-> '(2 3 5)) ⇒ (2 3 5) (-some-> 5 square) ⇒ 25 (-some-> 5 even? square) ⇒ nil -- Macro: -some->> (x &optional form &rest more) When expr is non-‘nil’, thread it through the first form (via ‘->>’ (*note ->>::)), and when that result is non-‘nil’, through the next form, etc. (-some->> '(1 2 3) (-map 'square)) ⇒ (1 4 9) (-some->> '(1 3 5) (-last 'even?) (+ 100)) ⇒ nil (-some->> '(2 4 6) (-last 'even?) (+ 100)) ⇒ 106 -- Macro: -some--> (expr &rest forms) Thread EXPR through FORMS via ‘-->’ (*note -->::), while the result is non-‘nil’. When EXPR evaluates to non-‘nil’, thread the result through the first of FORMS, and when that result is non-‘nil’, thread it through the next form, etc. (-some--> "def" (concat "abc" it "ghi")) ⇒ "abcdefghi" (-some--> nil (concat "abc" it "ghi")) ⇒ nil (-some--> '(0 1) (-remove #'natnump it) (append it it) (-map #'1+ it)) ⇒ () -- Macro: -doto (init &rest forms) Evaluate INIT and pass it as argument to FORMS with ‘->’ (*note ->::). The RESULT of evaluating INIT is threaded through each of FORMS individually using ‘->’ (*note ->::), which see. The return value is RESULT, which FORMS may have modified by side effect. (-doto (list 1 2 3) pop pop) ⇒ (3) (-doto (cons 1 2) (setcar 3) (setcdr 4)) ⇒ (3 . 4) (gethash 'k (--doto (make-hash-table) (puthash 'k 'v it))) ⇒ v  File: dash.info, Node: Binding, Next: Side effects, Prev: Threading macros, Up: Functions 2.13 Binding ============ Macros that combine ‘let’ and ‘let*’ with destructuring and flow control. -- Macro: -when-let ((var val) &rest body) If VAL evaluates to non-‘nil’, bind it to VAR and execute body. Note: binding is done according to ‘-let’ (*note -let::). (-when-let (match-index (string-match "d" "abcd")) (+ match-index 2)) ⇒ 5 (-when-let ((&plist :foo foo) (list :foo "foo")) foo) ⇒ "foo" (-when-let ((&plist :foo foo) (list :bar "bar")) foo) ⇒ nil -- Macro: -when-let* (vars-vals &rest body) If all VALS evaluate to true, bind them to their corresponding VARS and execute body. VARS-VALS should be a list of (VAR VAL) pairs. Note: binding is done according to ‘-let*’ (*note -let*::). VALS are evaluated sequentially, and evaluation stops after the first ‘nil’ VAL is encountered. (-when-let* ((x 5) (y 3) (z (+ y 4))) (+ x y z)) ⇒ 15 (-when-let* ((x 5) (y nil) (z 7)) (+ x y z)) ⇒ nil -- Macro: -if-let ((var val) then &rest else) If VAL evaluates to non-‘nil’, bind it to VAR and do THEN, otherwise do ELSE. Note: binding is done according to ‘-let’ (*note -let::). (-if-let (match-index (string-match "d" "abc")) (+ match-index 3) 7) ⇒ 7 (--if-let (even? 4) it nil) ⇒ t -- Macro: -if-let* (vars-vals then &rest else) If all VALS evaluate to true, bind them to their corresponding VARS and do THEN, otherwise do ELSE. VARS-VALS should be a list of (VAR VAL) pairs. Note: binding is done according to ‘-let*’ (*note -let*::). VALS are evaluated sequentially, and evaluation stops after the first ‘nil’ VAL is encountered. (-if-let* ((x 5) (y 3) (z 7)) (+ x y z) "foo") ⇒ 15 (-if-let* ((x 5) (y nil) (z 7)) (+ x y z) "foo") ⇒ "foo" (-if-let* (((_ _ x) '(nil nil 7))) x) ⇒ 7 -- Macro: -let (varlist &rest body) Bind variables according to VARLIST then eval BODY. VARLIST is a list of lists of the form (PATTERN SOURCE). Each PATTERN is matched against the SOURCE "structurally". SOURCE is only evaluated once for each PATTERN. Each PATTERN is matched recursively, and can therefore contain sub-patterns which are matched against corresponding sub-expressions of SOURCE. All the SOURCEs are evalled before any symbols are bound (i.e. "in parallel"). If VARLIST only contains one (PATTERN SOURCE) element, you can optionally specify it using a vector and discarding the outer-most parens. Thus (-let ((PATTERN SOURCE)) ...) becomes (-let [PATTERN SOURCE] ...). ‘-let’ (*note -let::) uses a convention of not binding places (symbols) starting with _ whenever it’s possible. You can use this to skip over entries you don’t care about. However, this is not *always* possible (as a result of implementation) and these symbols might get bound to undefined values. Following is the overview of supported patterns. Remember that patterns can be matched recursively, so every a, b, aK in the following can be a matching construct and not necessarily a symbol/variable. Symbol: a - bind the SOURCE to A. This is just like regular ‘let’. Conses and lists: (a) - bind ‘car’ of cons/list to A (a . b) - bind car of cons to A and ‘cdr’ to B (a b) - bind car of list to A and ‘cadr’ to B (a1 a2 a3 ...) - bind 0th car of list to A1, 1st to A2, 2nd to A3... (a1 a2 a3 ... aN . rest) - as above, but bind the Nth cdr to REST. Vectors: [a] - bind 0th element of a non-list sequence to A (works with vectors, strings, bit arrays...) [a1 a2 a3 ...] - bind 0th element of non-list sequence to A0, 1st to A1, 2nd to A2, ... If the PATTERN is shorter than SOURCE, the values at places not in PATTERN are ignored. If the PATTERN is longer than SOURCE, an ‘error’ is thrown. [a1 a2 a3 ... &rest rest] - as above, but bind the rest of the sequence to REST. This is conceptually the same as improper list matching (a1 a2 ... aN . rest) Key/value stores: (&plist key0 a0 ... keyN aN) - bind value mapped by keyK in the SOURCE plist to aK. If the value is not found, aK is ‘nil’. Uses ‘plist-get’ to fetch values. (&alist key0 a0 ... keyN aN) - bind value mapped by keyK in the SOURCE alist to aK. If the value is not found, aK is ‘nil’. Uses ‘assoc’ to fetch values. (&hash key0 a0 ... keyN aN) - bind value mapped by keyK in the SOURCE hash table to aK. If the value is not found, aK is ‘nil’. Uses ‘gethash’ to fetch values. Further, special keyword &keys supports "inline" matching of plist-like key-value pairs, similarly to &keys keyword of ‘cl-defun’. (a1 a2 ... aN &keys key1 b1 ... keyN bK) This binds N values from the list to a1 ... aN, then interprets the cdr as a plist (see key/value matching above). A shorthand notation for kv-destructuring exists which allows the patterns be optionally left out and derived from the key name in the following fashion: - a key :foo is converted into ‘foo’ pattern, - a key ’bar is converted into ‘bar’ pattern, - a key "baz" is converted into ‘baz’ pattern. That is, the entire value under the key is bound to the derived variable without any further destructuring. This is possible only when the form following the key is not a valid pattern (i.e. not a symbol, a cons cell or a vector). Otherwise the matching proceeds as usual and in case of an invalid spec fails with an error. Thus the patterns are normalized as follows: ;; derive all the missing patterns (&plist :foo ’bar "baz") => (&plist :foo foo ’bar bar "baz" baz) ;; we can specify some but not others (&plist :foo ’bar explicit-bar) => (&plist :foo foo ’bar explicit-bar) ;; nothing happens, we store :foo in x (&plist :foo x) => (&plist :foo x) ;; nothing happens, we match recursively (&plist :foo (a b c)) => (&plist :foo (a b c)) You can name the source using the syntax SYMBOL &as PATTERN. This syntax works with lists (proper or improper), vectors and all types of maps. (list &as a b c) (list 1 2 3) binds A to 1, B to 2, C to 3 and LIST to (1 2 3). Similarly: (bounds &as beg . end) (cons 1 2) binds BEG to 1, END to 2 and BOUNDS to (1 . 2). (items &as first . rest) (list 1 2 3) binds FIRST to 1, REST to (2 3) and ITEMS to (1 2 3) [vect &as _ b c] [1 2 3] binds B to 2, C to 3 and VECT to [1 2 3] (_ avoids binding as usual). (plist &as &plist :b b) (list :a 1 :b 2 :c 3) binds B to 2 and PLIST to (:a 1 :b 2 :c 3). Same for &alist and &hash. This is especially useful when we want to capture the result of a computation and destructure at the same time. Consider the form (function-returning-complex-structure) returning a list of two vectors with two items each. We want to capture this entire result and pass it to another computation, but at the same time we want to get the second item from each vector. We can achieve it with pattern (result &as [_ a] [_ b]) (function-returning-complex-structure) Note: Clojure programmers may know this feature as the ":as binding". The difference is that we put the &as at the front because we need to support improper list binding. (-let (([a (b c) d] [1 (2 3) 4])) (list a b c d)) ⇒ (1 2 3 4) (-let [(a b c . d) (list 1 2 3 4 5 6)] (list a b c d)) ⇒ (1 2 3 (4 5 6)) (-let [(&plist :foo foo :bar bar) (list :baz 3 :foo 1 :qux 4 :bar 2)] (list foo bar)) ⇒ (1 2) -- Macro: -let* (varlist &rest body) Bind variables according to VARLIST then eval BODY. VARLIST is a list of lists of the form (PATTERN SOURCE). Each PATTERN is matched against the SOURCE structurally. SOURCE is only evaluated once for each PATTERN. Each SOURCE can refer to the symbols already bound by this VARLIST. This is useful if you want to destructure SOURCE recursively but also want to name the intermediate structures. See ‘-let’ (*note -let::) for the list of all possible patterns. (-let* (((a . b) (cons 1 2)) ((c . d) (cons 3 4))) (list a b c d)) ⇒ (1 2 3 4) (-let* (((a . b) (cons 1 (cons 2 3))) ((c . d) b)) (list a b c d)) ⇒ (1 (2 . 3) 2 3) (-let* (((&alist "foo" foo "bar" bar) (list (cons "foo" 1) (cons "bar" (list 'a 'b 'c)))) ((a b c) bar)) (list foo a b c bar)) ⇒ (1 a b c (a b c)) -- Macro: -lambda (match-form &rest body) Return a lambda which destructures its input as MATCH-FORM and executes BODY. Note that you have to enclose the MATCH-FORM in a pair of parens, such that: (-lambda (x) body) (-lambda (x y ...) body) has the usual semantics of ‘lambda’. Furthermore, these get translated into normal ‘lambda’, so there is no performance penalty. See ‘-let’ (*note -let::) for a description of the destructuring mechanism. (-map (-lambda ((x y)) (+ x y)) '((1 2) (3 4) (5 6))) ⇒ (3 7 11) (-map (-lambda ([x y]) (+ x y)) '([1 2] [3 4] [5 6])) ⇒ (3 7 11) (funcall (-lambda ((_ . a) (_ . b)) (-concat a b)) '(1 2 3) '(4 5 6)) ⇒ (2 3 5 6) -- Macro: -setq ([match-form val] ...) Bind each MATCH-FORM to the value of its VAL. MATCH-FORM destructuring is done according to the rules of ‘-let’ (*note -let::). This macro allows you to bind multiple variables by destructuring the value, so for example: (-setq (a b) x (&plist :c c) plist) expands roughly speaking to the following code (setq a (car x) b (cadr x) c (plist-get plist :c)) Care is taken to only evaluate each VAL once so that in case of multiple assignments it does not cause unexpected side effects. (let (a) (-setq a 1) a) ⇒ 1 (let (a b) (-setq (a b) (list 1 2)) (list a b)) ⇒ (1 2) (let (c) (-setq (&plist :c c) (list :c "c")) c) ⇒ "c"  File: dash.info, Node: Side effects, Next: Destructive operations, Prev: Binding, Up: Functions 2.14 Side effects ================= Functions iterating over lists for side effect only. -- Function: -each (list fn) Call FN on each element of LIST. Return ‘nil’; this function is intended for side effects. Its anaphoric counterpart is ‘--each’. For access to the current element’s index in LIST, see ‘-each-indexed’ (*note -each-indexed::). (let (l) (-each '(1 2 3) (lambda (x) (push x l))) l) ⇒ (3 2 1) (let (l) (--each '(1 2 3) (push it l)) l) ⇒ (3 2 1) (-each '(1 2 3) #'identity) ⇒ nil -- Function: -each-while (list pred fn) Call FN on each ITEM in LIST, while (PRED ITEM) is non-‘nil’. Once an ITEM is reached for which PRED returns ‘nil’, FN is no longer called. Return ‘nil’; this function is intended for side effects. Its anaphoric counterpart is ‘--each-while’. (let (l) (-each-while '(2 4 5 6) #'even? (lambda (x) (push x l))) l) ⇒ (4 2) (let (l) (--each-while '(1 2 3 4) (< it 3) (push it l)) l) ⇒ (2 1) (let ((s 0)) (--each-while '(1 3 4 5) (< it 5) (setq s (+ s it))) s) ⇒ 8 -- Function: -each-indexed (list fn) Call FN on each index and element of LIST. For each ITEM at INDEX in LIST, call (funcall FN INDEX ITEM). Return ‘nil’; this function is intended for side effects. See also: ‘-map-indexed’ (*note -map-indexed::). (let (l) (-each-indexed '(a b c) (lambda (i x) (push (list x i) l))) l) ⇒ ((c 2) (b 1) (a 0)) (let (l) (--each-indexed '(a b c) (push (list it it-index) l)) l) ⇒ ((c 2) (b 1) (a 0)) (let (l) (--each-indexed () (push it l)) l) ⇒ () -- Function: -each-r (list fn) Call FN on each element of LIST in reversed order. Return ‘nil’; this function is intended for side effects. Its anaphoric counterpart is ‘--each-r’. (let (l) (-each-r '(1 2 3) (lambda (x) (push x l))) l) ⇒ (1 2 3) (let (l) (--each-r '(1 2 3) (push it l)) l) ⇒ (1 2 3) (-each-r '(1 2 3) #'identity) ⇒ nil -- Function: -each-r-while (list pred fn) Call FN on each ITEM in reversed LIST, while (PRED ITEM) is non-‘nil’. Once an ITEM is reached for which PRED returns ‘nil’, FN is no longer called. Return ‘nil’; this function is intended for side effects. Its anaphoric counterpart is ‘--each-r-while’. (let (l) (-each-r-while '(2 4 5 6) #'even? (lambda (x) (push x l))) l) ⇒ (6) (let (l) (--each-r-while '(1 2 3 4) (>= it 3) (push it l)) l) ⇒ (3 4) (let ((s 0)) (--each-r-while '(1 2 3 5) (> it 1) (setq s (+ s it))) s) ⇒ 10 -- Function: -dotimes (num fn) Call FN NUM times, presumably for side effects. FN is called with a single argument on successive integers running from 0, inclusive, to NUM, exclusive. FN is not called if NUM is less than 1. This function’s anaphoric counterpart is ‘--dotimes’. (let (s) (-dotimes 3 (lambda (n) (push n s))) s) ⇒ (2 1 0) (let (s) (-dotimes 0 (lambda (n) (push n s))) s) ⇒ () (let (s) (--dotimes 5 (push it s)) s) ⇒ (4 3 2 1 0)  File: dash.info, Node: Destructive operations, Next: Function combinators, Prev: Side effects, Up: Functions 2.15 Destructive operations =========================== Macros that modify variables holding lists. -- Macro: !cons (car cdr) Destructive: Set CDR to the cons of CAR and CDR. (let (l) (!cons 5 l) l) ⇒ (5) (let ((l '(3))) (!cons 5 l) l) ⇒ (5 3) -- Macro: !cdr (list) Destructive: Set LIST to the cdr of LIST. (let ((l '(3))) (!cdr l) l) ⇒ () (let ((l '(3 5))) (!cdr l) l) ⇒ (5)  File: dash.info, Node: Function combinators, Prev: Destructive operations, Up: Functions 2.16 Function combinators ========================= Functions that manipulate and compose other functions. -- Function: -partial (fun &rest args) Return a function that is a partial application of FUN to ARGS. ARGS is a list of the first N arguments to pass to FUN. The result is a new function which does the same as FUN, except that the first N arguments are fixed at the values with which this function was called. (funcall (-partial #'+ 5)) ⇒ 5 (funcall (-partial #'- 5) 3) ⇒ 2 (funcall (-partial #'+ 5 2) 3) ⇒ 10 -- Function: -rpartial (fn &rest args) Return a function that is a partial application of FN to ARGS. ARGS is a list of the last N arguments to pass to FN. The result is a new function which does the same as FN, except that the last N arguments are fixed at the values with which this function was called. This is like ‘-partial’ (*note -partial::), except the arguments are fixed starting from the right rather than the left. (funcall (-rpartial #'- 5)) ⇒ -5 (funcall (-rpartial #'- 5) 8) ⇒ 3 (funcall (-rpartial #'- 5 2) 10) ⇒ 3 -- Function: -juxt (&rest fns) Return a function that is the juxtaposition of FNS. The returned function takes a variable number of ARGS, applies each of FNS in turn to ARGS, and returns the list of results. (funcall (-juxt) 1 2) ⇒ () (funcall (-juxt #'+ #'- #'* #'/) 7 5) ⇒ (12 2 35 1) (mapcar (-juxt #'number-to-string #'1+) '(1 2)) ⇒ (("1" 2) ("2" 3)) -- Function: -compose (&rest fns) Compose FNS into a single composite function. Return a function that takes a variable number of ARGS, applies the last function in FNS to ARGS, and returns the result of calling each remaining function on the result of the previous function, right-to-left. If no FNS are given, return a variadic ‘identity’ function. (funcall (-compose #'- #'1+ #'+) 1 2 3) ⇒ -7 (funcall (-compose #'identity #'1+) 3) ⇒ 4 (mapcar (-compose #'not #'stringp) '(nil "")) ⇒ (t nil) -- Function: -applify (fn) Return a function that applies FN to a single list of args. This changes the arity of FN from taking N distinct arguments to taking 1 argument which is a list of N arguments. (funcall (-applify #'+) nil) ⇒ 0 (mapcar (-applify #'+) '((1 1 1) (1 2 3) (5 5 5))) ⇒ (3 6 15) (funcall (-applify #'<) '(3 6)) ⇒ t -- Function: -on (op trans) Return a function that calls TRANS on each arg and OP on the results. The returned function takes a variable number of arguments, calls the function TRANS on each one in turn, and then passes those results as the list of arguments to OP, in the same order. For example, the following pairs of expressions are morally equivalent: (funcall (-on #’+ #’1+) 1 2 3) = (+ (1+ 1) (1+ 2) (1+ 3)) (funcall (-on #’+ #’1+)) = (+) (-sort (-on #'< #'length) '((1 2 3) (1) (1 2))) ⇒ ((1) (1 2) (1 2 3)) (funcall (-on #'min #'string-to-number) "22" "2" "1" "12") ⇒ 1 (-min-by (-on #'> #'length) '((1 2 3) (4) (1 2))) ⇒ (4) -- Function: -flip (fn) Return a function that calls FN with its arguments reversed. The returned function takes the same number of arguments as FN. For example, the following two expressions are morally equivalent: (funcall (-flip #’-) 1 2) = (- 2 1) See also: ‘-rotate-args’ (*note -rotate-args::). (-sort (-flip #'<) '(4 3 6 1)) ⇒ (6 4 3 1) (funcall (-flip #'-) 3 2 1 10) ⇒ 4 (funcall (-flip #'1+) 1) ⇒ 2 -- Function: -rotate-args (n fn) Return a function that calls FN with args rotated N places to the right. The returned function takes the same number of arguments as FN, rotates the list of arguments N places to the right (left if N is negative) just like ‘-rotate’ (*note -rotate::), and applies FN to the result. See also: ‘-flip’ (*note -flip::). (funcall (-rotate-args -1 #'list) 1 2 3 4) ⇒ (2 3 4 1) (funcall (-rotate-args 1 #'-) 1 10 100) ⇒ 89 (funcall (-rotate-args 2 #'list) 3 4 5 1 2) ⇒ (1 2 3 4 5) -- Function: -const (c) Return a function that returns C ignoring any additional arguments. In types: a -> b -> a (funcall (-const 2) 1 3 "foo") ⇒ 2 (mapcar (-const 1) '("a" "b" "c" "d")) ⇒ (1 1 1 1) (-sum (mapcar (-const 1) '("a" "b" "c" "d"))) ⇒ 4 -- Macro: -cut (&rest params) Take n-ary function and n arguments and specialize some of them. Arguments denoted by <> will be left unspecialized. See SRFI-26 for detailed description. (funcall (-cut list 1 <> 3 <> 5) 2 4) ⇒ (1 2 3 4 5) (-map (-cut funcall <> 5) `(1+ 1- ,(lambda (x) (/ 1.0 x)))) ⇒ (6 4 0.2) (-map (-cut <> 1 2 3) '(list vector string)) ⇒ ((1 2 3) [1 2 3] "\1\2\3") -- Function: -not (pred) Return a predicate that negates the result of PRED. The returned predicate passes its arguments to PRED. If PRED returns ‘nil’, the result is non-‘nil’; otherwise the result is ‘nil’. See also: ‘-andfn’ (*note -andfn::) and ‘-orfn’ (*note -orfn::). (funcall (-not #'numberp) "5") ⇒ t (-sort (-not #'<) '(5 2 1 0 6)) ⇒ (6 5 2 1 0) (-filter (-not (-partial #'< 4)) '(1 2 3 4 5 6 7 8)) ⇒ (1 2 3 4) -- Function: -orfn (&rest preds) Return a predicate that returns the first non-‘nil’ result of PREDS. The returned predicate takes a variable number of arguments, passes them to each predicate in PREDS in turn until one of them returns non-‘nil’, and returns that non-‘nil’ result without calling the remaining PREDS. If all PREDS return ‘nil’, or if no PREDS are given, the returned predicate returns ‘nil’. See also: ‘-andfn’ (*note -andfn::) and ‘-not’ (*note -not::). (-filter (-orfn #'natnump #'booleanp) '(1 nil "a" -4 b c t)) ⇒ (1 nil t) (funcall (-orfn #'symbolp (-cut string-match-p "x" <>)) "axe") ⇒ 1 (funcall (-orfn #'= #'+) 1 1) ⇒ t -- Function: -andfn (&rest preds) Return a predicate that returns non-‘nil’ if all PREDS do so. The returned predicate P takes a variable number of arguments and passes them to each predicate in PREDS in turn. If any one of PREDS returns ‘nil’, P also returns ‘nil’ without calling the remaining PREDS. If all PREDS return non-‘nil’, P returns the last such value. If no PREDS are given, P always returns non-‘nil’. See also: ‘-orfn’ (*note -orfn::) and ‘-not’ (*note -not::). (-filter (-andfn #'numberp (-cut < <> 5)) '(a 1 b 6 c 2)) ⇒ (1 2) (mapcar (-andfn #'numberp #'1+) '(a 1 b 6)) ⇒ (nil 2 nil 7) (funcall (-andfn #'= #'+) 1 1) ⇒ 2 -- Function: -iteratefn (fn n) Return a function FN composed N times with itself. FN is a unary function. If you need to use a function of higher arity, use ‘-applify’ (*note -applify::) first to turn it into a unary function. With n = 0, this acts as identity function. In types: (a -> a) -> Int -> a -> a. This function satisfies the following law: (funcall (-iteratefn fn n) init) = (-last-item (-iterate fn init (1+ n))). (funcall (-iteratefn (lambda (x) (* x x)) 3) 2) ⇒ 256 (funcall (-iteratefn '1+ 3) 1) ⇒ 4 (funcall (-iteratefn 'cdr 3) '(1 2 3 4 5)) ⇒ (4 5) -- Function: -fixfn (fn &optional equal-test halt-test) Return a function that computes the (least) fixpoint of FN. FN must be a unary function. The returned lambda takes a single argument, X, the initial value for the fixpoint iteration. The iteration halts when either of the following conditions is satisfied: 1. Iteration converges to the fixpoint, with equality being tested using EQUAL-TEST. If EQUAL-TEST is not specified, ‘equal’ is used. For functions over the floating point numbers, it may be necessary to provide an appropriate approximate comparison test. 2. HALT-TEST returns a non-‘nil’ value. HALT-TEST defaults to a simple counter that returns ‘t’ after ‘-fixfn-max-iterations’, to guard against infinite iteration. Otherwise, HALT-TEST must be a function that accepts a single argument, the current value of X, and returns non-‘nil’ as long as iteration should continue. In this way, a more sophisticated convergence test may be supplied by the caller. The return value of the lambda is either the fixpoint or, if iteration halted before converging, a cons with car ‘halted’ and cdr the final output from HALT-TEST. In types: (a -> a) -> a -> a. (funcall (-fixfn #'cos #'approx=) 0.7) ⇒ 0.7390851332151607 (funcall (-fixfn (lambda (x) (expt (+ x 10) 0.25))) 2.0) ⇒ 1.8555845286409378 (funcall (-fixfn #'sin #'approx=) 0.1) ⇒ (halted . t) -- Function: -prodfn (&rest fns) Return a function that applies each of FNS to each of a list of arguments. Takes a list of N functions and returns a function that takes a list of length N, applying Ith function to Ith element of the input list. Returns a list of length N. In types (for N=2): ((a -> b), (c -> d)) -> (a, c) -> (b, d) This function satisfies the following laws: (-compose (-prodfn f g ...) (-prodfn f’ g’ ...)) = (-prodfn (-compose f f’) (-compose g g’) ...) (-prodfn f g ...) = (-juxt (-compose f (-partial #’nth 0)) (-compose g (-partial #’nth 1)) ...) (-compose (-prodfn f g ...) (-juxt f’ g’ ...)) = (-juxt (-compose f f’) (-compose g g’) ...) (-compose (-partial #’nth n) (-prod f1 f2 ...)) = (-compose fn (-partial #’nth n)) (funcall (-prodfn #'1+ #'1- #'number-to-string) '(1 2 3)) ⇒ (2 1 "3") (-map (-prodfn #'1- #'1+) '((1 2) (3 4) (5 6))) ⇒ ((0 3) (2 5) (4 7)) (apply #'+ (funcall (-prodfn #'length #'string-to-number) '((t) "5"))) ⇒ 6  File: dash.info, Node: Development, Next: FDL, Prev: Functions, Up: Top 3 Development ************* The Dash repository is hosted on GitHub at . * Menu: * Contribute:: How to contribute. * Contributors:: List of contributors.  File: dash.info, Node: Contribute, Next: Contributors, Up: Development 3.1 Contribute ============== Yes, please do. Pure functions in the list manipulation realm only, please. There’s a suite of examples/tests in ‘dev/examples.el’, so remember to add tests for your additions, or they may get broken later. Run the tests with ‘make check’. Regenerate the docs with ‘make docs’. Contributors are encouraged to install these commands as a Git pre-commit hook, so that the tests are always running and the docs are always in sync: $ cp dev/pre-commit.sh .git/hooks/pre-commit Oh, and don’t edit ‘README.md’ or ‘dash.texi’ directly, as they are auto-generated. Instead, change their respective templates ‘readme-template.md’ or ‘dash-template.texi’. To ensure that Dash can be distributed with GNU ELPA or Emacs, we require that all contributors assign copyright to the Free Software Foundation. For more on this, *note (emacs)Copyright Assignment::.  File: dash.info, Node: Contributors, Prev: Contribute, Up: Development 3.2 Contributors ================ • Matus Goljer (https://github.com/Fuco1) contributed lots of features and functions. • Takafumi Arakaki (https://github.com/tkf) contributed ‘-group-by’. • tali713 (https://github.com/tali713) is the author of ‘-applify’. • Víctor M. Valenzuela (https://github.com/vemv) contributed ‘-repeat’. • Nic Ferrier (https://github.com/nicferrier) contributed ‘-cons*’. • Wilfred Hughes (https://github.com/Wilfred) contributed ‘-slice’, ‘-first-item’, and ‘-last-item’. • Emanuel Evans (https://github.com/shosti) contributed ‘-if-let’, ‘-when-let’, and ‘-insert-at’. • Johan Andersson (https://github.com/rejeep) contributed ‘-sum’, ‘-product’, and ‘-same-items?’. • Christina Whyte (https://github.com/kurisuwhyte) contributed ‘-compose’. • Steve Lamb (https://github.com/steventlamb) contributed ‘-cycle’, ‘-pad’, ‘-annotate’, ‘-zip-fill’, and a variadic version of ‘-zip’. • Fredrik Bergroth (https://github.com/fbergroth) made the ‘-if-let’ family use ‘-let’ destructuring and improved the script for generating documentation. • Mark Oteiza (https://github.com/holomorph) contributed ‘-iota’ and the script to create an Info manual. • Vasilij Schneidermann (https://github.com/wasamasa) contributed ‘-some’. • William West (https://github.com/occidens) made ‘-fixfn’ more robust at handling floats. • Cam Saul (https://github.com/camsaul) contributed ‘-some->’, ‘-some->>’, and ‘-some-->’. • Basil L. Contovounesios (https://github.com/basil-conto) contributed ‘-common-prefix’, ‘-common-suffix’, and various other improvements. • Paul Pogonyshev (https://github.com/doublep) contributed ‘-each-r’ and ‘-each-r-while’. Thanks! New contributors are very welcome. *Note Contribute::.  File: dash.info, Node: FDL, Next: GPL, Prev: Development, Up: Top Appendix A GNU Free Documentation License ***************************************** Version 1.3, 3 November 2008 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. 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The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing. ADDENDUM: How to use this License for your documents ==================================================== To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.  File: dash.info, Node: GPL, Next: Index, Prev: FDL, Up: Top Appendix B GNU General Public License ************************************* Version 3, 29 June 2007 Copyright © 2007 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble ======== The GNU General Public License is a free, copyleft license for software and other kinds of works. The licenses for most software and other practical works are designed to take away your freedom to share and change the works. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change all versions of a program—to make sure it remains free software for all its users. We, the Free Software Foundation, use the GNU General Public License for most of our software; it applies also to any other work released this way by its authors. You can apply it to your programs, too. When we speak of free software, we are referring to freedom, not price. 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Developers that use the GNU GPL protect your rights with two steps: (1) assert copyright on the software, and (2) offer you this License giving you legal permission to copy, distribute and/or modify it. For the developers’ and authors’ protection, the GPL clearly explains that there is no warranty for this free software. For both users’ and authors’ sake, the GPL requires that modified versions be marked as changed, so that their problems will not be attributed erroneously to authors of previous versions. Some devices are designed to deny users access to install or run modified versions of the software inside them, although the manufacturer can do so. This is fundamentally incompatible with the aim of protecting users’ freedom to change the software. The systematic pattern of such abuse occurs in the area of products for individuals to use, which is precisely where it is most unacceptable. Therefore, we have designed this version of the GPL to prohibit the practice for those products. If such problems arise substantially in other domains, we stand ready to extend this provision to those domains in future versions of the GPL, as needed to protect the freedom of users. Finally, every program is threatened constantly by software patents. States should not allow patents to restrict development and use of software on general-purpose computers, but in those that do, we wish to avoid the special danger that patents applied to a free program could make it effectively proprietary. To prevent this, the GPL assures that patents cannot be used to render the program non-free. The precise terms and conditions for copying, distribution and modification follow. TERMS AND CONDITIONS ==================== 0. Definitions. “This License” refers to version 3 of the GNU General Public License. “Copyright” also means copyright-like laws that apply to other kinds of works, such as semiconductor masks. “The Program” refers to any copyrightable work licensed under this License. Each licensee is addressed as “you”. “Licensees” and “recipients” may be individuals or organizations. To “modify” a work means to copy from or adapt all or part of the work in a fashion requiring copyright permission, other than the making of an exact copy. The resulting work is called a “modified version” of the earlier work or a work “based on” the earlier work. A “covered work” means either the unmodified Program or a work based on the Program. To “propagate” a work means to do anything with it that, without permission, would make you directly or secondarily liable for infringement under applicable copyright law, except executing it on a computer or modifying a private copy. Propagation includes copying, distribution (with or without modification), making available to the public, and in some countries other activities as well. To “convey” a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user through a computer network, with no transfer of a copy, is not conveying. An interactive user interface displays “Appropriate Legal Notices” to the extent that it includes a convenient and prominently visible feature that (1) displays an appropriate copyright notice, and (2) tells the user that there is no warranty for the work (except to the extent that warranties are provided), that licensees may convey the work under this License, and how to view a copy of this License. If the interface presents a list of user commands or options, such as a menu, a prominent item in the list meets this criterion. 1. Source Code. The “source code” for a work means the preferred form of the work for making modifications to it. “Object code” means any non-source form of a work. A “Standard Interface” means an interface that either is an official standard defined by a recognized standards body, or, in the case of interfaces specified for a particular programming language, one that is widely used among developers working in that language. The “System Libraries” of an executable work include anything, other than the work as a whole, that (a) is included in the normal form of packaging a Major Component, but which is not part of that Major Component, and (b) serves only to enable use of the work with that Major Component, or to implement a Standard Interface for which an implementation is available to the public in source code form. A “Major Component”, in this context, means a major essential component (kernel, window system, and so on) of the specific operating system (if any) on which the executable work runs, or a compiler used to produce the work, or an object code interpreter used to run it. The “Corresponding Source” for a work in object code form means all the source code needed to generate, install, and (for an executable work) run the object code and to modify the work, including scripts to control those activities. However, it does not include the work’s System Libraries, or general-purpose tools or generally available free programs which are used unmodified in performing those activities but which are not part of the work. For example, Corresponding Source includes interface definition files associated with source files for the work, and the source code for shared libraries and dynamically linked subprograms that the work is specifically designed to require, such as by intimate data communication or control flow between those subprograms and other parts of the work. The Corresponding Source need not include anything that users can regenerate automatically from other parts of the Corresponding Source. The Corresponding Source for a work in source code form is that same work. 2. Basic Permissions. All rights granted under this License are granted for the term of copyright on the Program, and are irrevocable provided the stated conditions are met. This License explicitly affirms your unlimited permission to run the unmodified Program. The output from running a covered work is covered by this License only if the output, given its content, constitutes a covered work. This License acknowledges your rights of fair use or other equivalent, as provided by copyright law. You may make, run and propagate covered works that you do not convey, without conditions so long as your license otherwise remains in force. You may convey covered works to others for the sole purpose of having them make modifications exclusively for you, or provide you with facilities for running those works, provided that you comply with the terms of this License in conveying all material for which you do not control copyright. Those thus making or running the covered works for you must do so exclusively on your behalf, under your direction and control, on terms that prohibit them from making any copies of your copyrighted material outside their relationship with you. Conveying under any other circumstances is permitted solely under the conditions stated below. Sublicensing is not allowed; section 10 makes it unnecessary. 3. Protecting Users’ Legal Rights From Anti-Circumvention Law. No covered work shall be deemed part of an effective technological measure under any applicable law fulfilling obligations under article 11 of the WIPO copyright treaty adopted on 20 December 1996, or similar laws prohibiting or restricting circumvention of such measures. When you convey a covered work, you waive any legal power to forbid circumvention of technological measures to the extent such circumvention is effected by exercising rights under this License with respect to the covered work, and you disclaim any intention to limit operation or modification of the work as a means of enforcing, against the work’s users, your or third parties’ legal rights to forbid circumvention of technological measures. 4. Conveying Verbatim Copies. You may convey verbatim copies of the Program’s source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice; keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty; and give all recipients a copy of this License along with the Program. You may charge any price or no price for each copy that you convey, and you may offer support or warranty protection for a fee. 5. Conveying Modified Source Versions. You may convey a work based on the Program, or the modifications to produce it from the Program, in the form of source code under the terms of section 4, provided that you also meet all of these conditions: a. The work must carry prominent notices stating that you modified it, and giving a relevant date. b. The work must carry prominent notices stating that it is released under this License and any conditions added under section 7. This requirement modifies the requirement in section 4 to “keep intact all notices”. c. You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy. This License will therefore apply, along with any applicable section 7 additional terms, to the whole of the work, and all its parts, regardless of how they are packaged. This License gives no permission to license the work in any other way, but it does not invalidate such permission if you have separately received it. d. If the work has interactive user interfaces, each must display Appropriate Legal Notices; however, if the Program has interactive interfaces that do not display Appropriate Legal Notices, your work need not make them do so. A compilation of a covered work with other separate and independent works, which are not by their nature extensions of the covered work, and which are not combined with it such as to form a larger program, in or on a volume of a storage or distribution medium, is called an “aggregate” if the compilation and its resulting copyright are not used to limit the access or legal rights of the compilation’s users beyond what the individual works permit. Inclusion of a covered work in an aggregate does not cause this License to apply to the other parts of the aggregate. 6. Conveying Non-Source Forms. You may convey a covered work in object code form under the terms of sections 4 and 5, provided that you also convey the machine-readable Corresponding Source under the terms of this License, in one of these ways: a. Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by the Corresponding Source fixed on a durable physical medium customarily used for software interchange. b. Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by a written offer, valid for at least three years and valid for as long as you offer spare parts or customer support for that product model, to give anyone who possesses the object code either (1) a copy of the Corresponding Source for all the software in the product that is covered by this License, on a durable physical medium customarily used for software interchange, for a price no more than your reasonable cost of physically performing this conveying of source, or (2) access to copy the Corresponding Source from a network server at no charge. c. Convey individual copies of the object code with a copy of the written offer to provide the Corresponding Source. This alternative is allowed only occasionally and noncommercially, and only if you received the object code with such an offer, in accord with subsection 6b. d. Convey the object code by offering access from a designated place (gratis or for a charge), and offer equivalent access to the Corresponding Source in the same way through the same place at no further charge. You need not require recipients to copy the Corresponding Source along with the object code. If the place to copy the object code is a network server, the Corresponding Source may be on a different server (operated by you or a third party) that supports equivalent copying facilities, provided you maintain clear directions next to the object code saying where to find the Corresponding Source. Regardless of what server hosts the Corresponding Source, you remain obligated to ensure that it is available for as long as needed to satisfy these requirements. e. Convey the object code using peer-to-peer transmission, provided you inform other peers where the object code and Corresponding Source of the work are being offered to the general public at no charge under subsection 6d. A separable portion of the object code, whose source code is excluded from the Corresponding Source as a System Library, need not be included in conveying the object code work. A “User Product” is either (1) a “consumer product”, which means any tangible personal property which is normally used for personal, family, or household purposes, or (2) anything designed or sold for incorporation into a dwelling. In determining whether a product is a consumer product, doubtful cases shall be resolved in favor of coverage. For a particular product received by a particular user, “normally used” refers to a typical or common use of that class of product, regardless of the status of the particular user or of the way in which the particular user actually uses, or expects or is expected to use, the product. A product is a consumer product regardless of whether the product has substantial commercial, industrial or non-consumer uses, unless such uses represent the only significant mode of use of the product. “Installation Information” for a User Product means any methods, procedures, authorization keys, or other information required to install and execute modified versions of a covered work in that User Product from a modified version of its Corresponding Source. The information must suffice to ensure that the continued functioning of the modified object code is in no case prevented or interfered with solely because modification has been made. If you convey an object code work under this section in, or with, or specifically for use in, a User Product, and the conveying occurs as part of a transaction in which the right of possession and use of the User Product is transferred to the recipient in perpetuity or for a fixed term (regardless of how the transaction is characterized), the Corresponding Source conveyed under this section must be accompanied by the Installation Information. But this requirement does not apply if neither you nor any third party retains the ability to install modified object code on the User Product (for example, the work has been installed in ROM). The requirement to provide Installation Information does not include a requirement to continue to provide support service, warranty, or updates for a work that has been modified or installed by the recipient, or for the User Product in which it has been modified or installed. Access to a network may be denied when the modification itself materially and adversely affects the operation of the network or violates the rules and protocols for communication across the network. Corresponding Source conveyed, and Installation Information provided, in accord with this section must be in a format that is publicly documented (and with an implementation available to the public in source code form), and must require no special password or key for unpacking, reading or copying. 7. Additional Terms. “Additional permissions” are terms that supplement the terms of this License by making exceptions from one or more of its conditions. Additional permissions that are applicable to the entire Program shall be treated as though they were included in this License, to the extent that they are valid under applicable law. If additional permissions apply only to part of the Program, that part may be used separately under those permissions, but the entire Program remains governed by this License without regard to the additional permissions. When you convey a copy of a covered work, you may at your option remove any additional permissions from that copy, or from any part of it. (Additional permissions may be written to require their own removal in certain cases when you modify the work.) You may place additional permissions on material, added by you to a covered work, for which you have or can give appropriate copyright permission. Notwithstanding any other provision of this License, for material you add to a covered work, you may (if authorized by the copyright holders of that material) supplement the terms of this License with terms: a. Disclaiming warranty or limiting liability differently from the terms of sections 15 and 16 of this License; or b. Requiring preservation of specified reasonable legal notices or author attributions in that material or in the Appropriate Legal Notices displayed by works containing it; or c. Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version; or d. Limiting the use for publicity purposes of names of licensors or authors of the material; or e. Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks; or f. Requiring indemnification of licensors and authors of that material by anyone who conveys the material (or modified versions of it) with contractual assumptions of liability to the recipient, for any liability that these contractual assumptions directly impose on those licensors and authors. All other non-permissive additional terms are considered “further restrictions” within the meaning of section 10. If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term. If a license document contains a further restriction but permits relicensing or conveying under this License, you may add to a covered work material governed by the terms of that license document, provided that the further restriction does not survive such relicensing or conveying. If you add terms to a covered work in accord with this section, you must place, in the relevant source files, a statement of the additional terms that apply to those files, or a notice indicating where to find the applicable terms. Additional terms, permissive or non-permissive, may be stated in the form of a separately written license, or stated as exceptions; the above requirements apply either way. 8. Termination. You may not propagate or modify a covered work except as expressly provided under this License. Any attempt otherwise to propagate or modify it is void, and will automatically terminate your rights under this License (including any patent licenses granted under the third paragraph of section 11). However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation. Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice. Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, you do not qualify to receive new licenses for the same material under section 10. 9. Acceptance Not Required for Having Copies. You are not required to accept this License in order to receive or run a copy of the Program. Ancillary propagation of a covered work occurring solely as a consequence of using peer-to-peer transmission to receive a copy likewise does not require acceptance. However, nothing other than this License grants you permission to propagate or modify any covered work. These actions infringe copyright if you do not accept this License. Therefore, by modifying or propagating a covered work, you indicate your acceptance of this License to do so. 10. Automatic Licensing of Downstream Recipients. Each time you convey a covered work, the recipient automatically receives a license from the original licensors, to run, modify and propagate that work, subject to this License. You are not responsible for enforcing compliance by third parties with this License. An “entity transaction” is a transaction transferring control of an organization, or substantially all assets of one, or subdividing an organization, or merging organizations. If propagation of a covered work results from an entity transaction, each party to that transaction who receives a copy of the work also receives whatever licenses to the work the party’s predecessor in interest had or could give under the previous paragraph, plus a right to possession of the Corresponding Source of the work from the predecessor in interest, if the predecessor has it or can get it with reasonable efforts. You may not impose any further restrictions on the exercise of the rights granted or affirmed under this License. For example, you may not impose a license fee, royalty, or other charge for exercise of rights granted under this License, and you may not initiate litigation (including a cross-claim or counterclaim in a lawsuit) alleging that any patent claim is infringed by making, using, selling, offering for sale, or importing the Program or any portion of it. 11. Patents. A “contributor” is a copyright holder who authorizes use under this License of the Program or a work on which the Program is based. The work thus licensed is called the contributor’s “contributor version”. A contributor’s “essential patent claims” are all patent claims owned or controlled by the contributor, whether already acquired or hereafter acquired, that would be infringed by some manner, permitted by this License, of making, using, or selling its contributor version, but do not include claims that would be infringed only as a consequence of further modification of the contributor version. For purposes of this definition, “control” includes the right to grant patent sublicenses in a manner consistent with the requirements of this License. Each contributor grants you a non-exclusive, worldwide, royalty-free patent license under the contributor’s essential patent claims, to make, use, sell, offer for sale, import and otherwise run, modify and propagate the contents of its contributor version. In the following three paragraphs, a “patent license” is any express agreement or commitment, however denominated, not to enforce a patent (such as an express permission to practice a patent or covenant not to sue for patent infringement). To “grant” such a patent license to a party means to make such an agreement or commitment not to enforce a patent against the party. If you convey a covered work, knowingly relying on a patent license, and the Corresponding Source of the work is not available for anyone to copy, free of charge and under the terms of this License, through a publicly available network server or other readily accessible means, then you must either (1) cause the Corresponding Source to be so available, or (2) arrange to deprive yourself of the benefit of the patent license for this particular work, or (3) arrange, in a manner consistent with the requirements of this License, to extend the patent license to downstream recipients. “Knowingly relying” means you have actual knowledge that, but for the patent license, your conveying the covered work in a country, or your recipient’s use of the covered work in a country, would infringe one or more identifiable patents in that country that you have reason to believe are valid. If, pursuant to or in connection with a single transaction or arrangement, you convey, or propagate by procuring conveyance of, a covered work, and grant a patent license to some of the parties receiving the covered work authorizing them to use, propagate, modify or convey a specific copy of the covered work, then the patent license you grant is automatically extended to all recipients of the covered work and works based on it. A patent license is “discriminatory” if it does not include within the scope of its coverage, prohibits the exercise of, or is conditioned on the non-exercise of one or more of the rights that are specifically granted under this License. You may not convey a covered work if you are a party to an arrangement with a third party that is in the business of distributing software, under which you make payment to the third party based on the extent of your activity of conveying the work, and under which the third party grants, to any of the parties who would receive the covered work from you, a discriminatory patent license (a) in connection with copies of the covered work conveyed by you (or copies made from those copies), or (b) primarily for and in connection with specific products or compilations that contain the covered work, unless you entered into that arrangement, or that patent license was granted, prior to 28 March 2007. Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law. 12. No Surrender of Others’ Freedom. If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program. 13. Use with the GNU Affero General Public License. Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such. 14. Revised Versions of this License. The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation. If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Program. Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version. 15. Disclaimer of Warranty. THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 16. Limitation of Liability. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 17. Interpretation of Sections 15 and 16. If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee. END OF TERMS AND CONDITIONS =========================== How to Apply These Terms to Your New Programs ============================================= If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found. ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. Copyright (C) YEAR NAME OF AUTHOR This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Also add information on how to contact you by electronic and paper mail. If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode: PROGRAM Copyright (C) YEAR NAME OF AUTHOR This program comes with ABSOLUTELY NO WARRANTY; for details type ‘show w’. This is free software, and you are welcome to redistribute it under certain conditions; type ‘show c’ for details. The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, your program’s commands might be different; for a GUI interface, you would use an “about box”. You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see . The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read .  File: dash.info, Node: Index, Prev: GPL, Up: Top Index ***** [index] * Menu: * !cdr: Destructive operations. (line 16) * !cons: Destructive operations. (line 8) * -->: Threading macros. (line 35) * ->: Threading macros. (line 9) * ->>: Threading macros. (line 22) * -all?: Predicates. (line 53) * -andfn: Function combinators. (line 184) * -annotate: Maps. (line 86) * -any?: Predicates. (line 41) * -applify: Function combinators. (line 63) * -as->: Threading macros. (line 49) * -butlast: Other list operations. (line 405) * -clone: Tree operations. (line 123) * -common-prefix: Reductions. (line 242) * -common-suffix: Reductions. (line 252) * -compose: Function combinators. (line 49) * -concat: List to list. (line 23) * -cons*: Other list operations. (line 19) * -cons-pair?: Predicates. (line 154) * -const: Function combinators. (line 128) * -contains?: Predicates. (line 100) * -copy: Maps. (line 151) * -count: Reductions. (line 172) * -cut: Function combinators. (line 140) * -cycle: Unfolding. (line 55) * -difference: Set operations. (line 22) * -distinct: Set operations. (line 73) * -dotimes: Side effects. (line 80) * -doto: Threading macros. (line 99) * -drop: Sublist selection. (line 149) * -drop-last: Sublist selection. (line 163) * -drop-while: Sublist selection. (line 194) * -each: Side effects. (line 8) * -each-indexed: Side effects. (line 38) * -each-r: Side effects. (line 52) * -each-r-while: Side effects. (line 65) * -each-while: Side effects. (line 24) * -elem-index: Indexing. (line 9) * -elem-indices: Indexing. (line 23) * -every: Predicates. (line 23) * -fifth-item: Other list operations. (line 380) * -filter: Sublist selection. (line 8) * -find-index: Indexing. (line 35) * -find-indices: Indexing. (line 73) * -find-last-index: Indexing. (line 54) * -first: Other list operations. (line 300) * -first-item: Other list operations. (line 328) * -fix: Other list operations. (line 445) * -fixfn: Function combinators. (line 224) * -flatten: List to list. (line 38) * -flatten-n: List to list. (line 60) * -flip: Function combinators. (line 95) * -fourth-item: Other list operations. (line 367) * -frequencies: Reductions. (line 310) * -grade-down: Indexing. (line 103) * -grade-up: Indexing. (line 93) * -group-by: Partitioning. (line 205) * -if-let: Binding. (line 34) * -if-let*: Binding. (line 45) * -inits: Reductions. (line 222) * -insert-at: List to list. (line 114) * -interleave: Other list operations. (line 56) * -interpose: Other list operations. (line 46) * -intersection: Set operations. (line 36) * -iota: Other list operations. (line 67) * -is-infix?: Predicates. (line 140) * -is-prefix?: Predicates. (line 116) * -is-suffix?: Predicates. (line 128) * -iterate: Unfolding. (line 9) * -iteratefn: Function combinators. (line 201) * -juxt: Function combinators. (line 37) * -keep: List to list. (line 8) * -lambda: Binding. (line 247) * -last: Other list operations. (line 318) * -last-item: Other list operations. (line 393) * -let: Binding. (line 61) * -let*: Binding. (line 227) * -list: Other list operations. (line 428) * -map: Maps. (line 10) * -map-first: Maps. (line 38) * -map-indexed: Maps. (line 68) * -map-last: Maps. (line 53) * -map-when: Maps. (line 22) * -mapcat: Maps. (line 140) * -max: Reductions. (line 286) * -max-by: Reductions. (line 296) * -min: Reductions. (line 262) * -min-by: Reductions. (line 272) * -non-nil: Sublist selection. (line 95) * -none?: Predicates. (line 73) * -not: Function combinators. (line 153) * -on: Function combinators. (line 75) * -only-some?: Predicates. (line 85) * -orfn: Function combinators. (line 167) * -pad: Other list operations. (line 241) * -partial: Function combinators. (line 8) * -partition: Partitioning. (line 90) * -partition-after-item: Partitioning. (line 195) * -partition-after-pred: Partitioning. (line 162) * -partition-all: Partitioning. (line 102) * -partition-all-in-steps: Partitioning. (line 126) * -partition-before-item: Partitioning. (line 185) * -partition-before-pred: Partitioning. (line 174) * -partition-by: Partitioning. (line 138) * -partition-by-header: Partitioning. (line 149) * -partition-in-steps: Partitioning. (line 113) * -permutations: Set operations. (line 60) * -powerset: Set operations. (line 50) * -prodfn: Function combinators. (line 258) * -product: Reductions. (line 201) * -reduce: Reductions. (line 53) * -reduce-from: Reductions. (line 8) * -reduce-r: Reductions. (line 72) * -reduce-r-from: Reductions. (line 26) * -reductions: Reductions. (line 136) * -reductions-from: Reductions. (line 100) * -reductions-r: Reductions. (line 154) * -reductions-r-from: Reductions. (line 118) * -remove: Sublist selection. (line 26) * -remove-at: List to list. (line 151) * -remove-at-indices: List to list. (line 170) * -remove-first: Sublist selection. (line 44) * -remove-item: Sublist selection. (line 84) * -remove-last: Sublist selection. (line 65) * -repeat: Unfolding. (line 44) * -replace: List to list. (line 72) * -replace-at: List to list. (line 125) * -replace-first: List to list. (line 86) * -replace-last: List to list. (line 100) * -rotate: Other list operations. (line 8) * -rotate-args: Function combinators. (line 112) * -rpartial: Function combinators. (line 22) * -running-product: Reductions. (line 211) * -running-sum: Reductions. (line 190) * -same-items?: Set operations. (line 88) * -second-item: Other list operations. (line 341) * -select-by-indices: Sublist selection. (line 211) * -select-column: Sublist selection. (line 241) * -select-columns: Sublist selection. (line 222) * -separate: Partitioning. (line 75) * -setq: Binding. (line 270) * -slice: Sublist selection. (line 105) * -snoc: Other list operations. (line 32) * -some: Predicates. (line 8) * -some-->: Threading macros. (line 86) * -some->: Threading macros. (line 62) * -some->>: Threading macros. (line 74) * -sort: Other list operations. (line 415) * -splice: Maps. (line 102) * -splice-list: Maps. (line 127) * -split-at: Partitioning. (line 8) * -split-on: Partitioning. (line 40) * -split-when: Partitioning. (line 58) * -split-with: Partitioning. (line 23) * -sum: Reductions. (line 180) * -table: Other list operations. (line 256) * -table-flat: Other list operations. (line 275) * -tails: Reductions. (line 232) * -take: Sublist selection. (line 121) * -take-last: Sublist selection. (line 135) * -take-while: Sublist selection. (line 177) * -third-item: Other list operations. (line 354) * -tree-map: Tree operations. (line 28) * -tree-map-nodes: Tree operations. (line 39) * -tree-mapreduce: Tree operations. (line 85) * -tree-mapreduce-from: Tree operations. (line 104) * -tree-reduce: Tree operations. (line 53) * -tree-reduce-from: Tree operations. (line 70) * -tree-seq: Tree operations. (line 8) * -unfold: Unfolding. (line 25) * -union: Set operations. (line 8) * -unzip: Other list operations. (line 215) * -unzip-lists: Other list operations. (line 196) * -update-at: List to list. (line 137) * -when-let: Binding. (line 9) * -when-let*: Binding. (line 21) * -zip: Other list operations. (line 150) * -zip-fill: Other list operations. (line 176) * -zip-lists: Other list operations. (line 114) * -zip-lists-fill: Other list operations. (line 135) * -zip-pair: Other list operations. (line 98) * -zip-with: Other list operations. (line 80) * dash-fontify-mode: Fontification of special variables. (line 6) * dash-register-info-lookup: Info symbol lookup. (line 6) * global-dash-fontify-mode: Fontification of special variables. (line 12)  Tag Table: Node: Top742 Node: Installation2397 Node: Using in a package3159 Node: Fontification of special variables3504 Node: Info symbol lookup4294 Node: Functions4877 Node: Maps6361 Ref: -map6658 Ref: -map-when7031 Ref: -map-first7605 Ref: -map-last8200 Ref: -map-indexed8790 Ref: -annotate9476 Ref: -splice10080 Ref: -splice-list11155 Ref: -mapcat11614 Ref: -copy11987 Node: Sublist selection12175 Ref: -filter12368 Ref: -remove12921 Ref: -remove-first13470 Ref: -remove-last14318 Ref: -remove-item15048 Ref: -non-nil15448 Ref: -slice15730 Ref: -take16259 Ref: -take-last16677 Ref: -drop17114 Ref: -drop-last17561 Ref: -take-while17993 Ref: -drop-while18620 Ref: -select-by-indices19253 Ref: -select-columns19764 Ref: -select-column20467 Node: List to list20930 Ref: -keep21122 Ref: -concat21698 Ref: -flatten22226 Ref: -flatten-n22988 Ref: -replace23372 Ref: -replace-first23833 Ref: -replace-last24328 Ref: -insert-at24816 Ref: -replace-at25141 Ref: -update-at25528 Ref: -remove-at26069 Ref: -remove-at-indices26696 Node: Reductions27386 Ref: -reduce-from27582 Ref: -reduce-r-from28306 Ref: -reduce29569 Ref: -reduce-r30320 Ref: -reductions-from31598 Ref: -reductions-r-from32404 Ref: -reductions33234 Ref: -reductions-r33945 Ref: -count34690 Ref: -sum34920 Ref: -running-sum35108 Ref: -product35429 Ref: -running-product35637 Ref: -inits35978 Ref: -tails36223 Ref: -common-prefix36467 Ref: -common-suffix36761 Ref: -min37055 Ref: -min-by37281 Ref: -max37802 Ref: -max-by38027 Ref: -frequencies38553 Node: Unfolding39168 Ref: -iterate39409 Ref: -unfold39856 Ref: -repeat40661 Ref: -cycle40945 Node: Predicates41342 Ref: -some41519 Ref: -every41948 Ref: -any?42662 Ref: -all?43011 Ref: -none?43753 Ref: -only-some?44073 Ref: -contains?44618 Ref: -is-prefix?45124 Ref: -is-suffix?45456 Ref: -is-infix?45788 Ref: -cons-pair?46148 Node: Partitioning46479 Ref: -split-at46667 Ref: -split-with47331 Ref: -split-on47971 Ref: -split-when48642 Ref: -separate49285 Ref: -partition49819 Ref: -partition-all50268 Ref: -partition-in-steps50693 Ref: -partition-all-in-steps51239 Ref: -partition-by51753 Ref: -partition-by-header52131 Ref: -partition-after-pred52732 Ref: -partition-before-pred53185 Ref: -partition-before-item53570 Ref: -partition-after-item53877 Ref: -group-by54179 Node: Indexing54612 Ref: -elem-index54814 Ref: -elem-indices55301 Ref: -find-index55760 Ref: -find-last-index56429 Ref: -find-indices57080 Ref: -grade-up57842 Ref: -grade-down58249 Node: Set operations58663 Ref: -union58846 Ref: -difference59276 Ref: -intersection59704 Ref: -powerset60133 Ref: -permutations60410 Ref: -distinct60848 Ref: -same-items?61242 Node: Other list operations61851 Ref: -rotate62076 Ref: -cons*62429 Ref: -snoc62851 Ref: -interpose63263 Ref: -interleave63557 Ref: -iota63923 Ref: -zip-with64406 Ref: -zip-pair65214 Ref: -zip-lists65780 Ref: -zip-lists-fill66578 Ref: -zip67288 Ref: -zip-fill68315 Ref: -unzip-lists69229 Ref: -unzip69852 Ref: -pad70845 Ref: -table71330 Ref: -table-flat72116 Ref: -first73121 Ref: -last73654 Ref: -first-item74000 Ref: -second-item74412 Ref: -third-item74829 Ref: -fourth-item75204 Ref: -fifth-item75582 Ref: -last-item75957 Ref: -butlast76318 Ref: -sort76563 Ref: -list77055 Ref: -fix77624 Node: Tree operations78113 Ref: -tree-seq78309 Ref: -tree-map79170 Ref: -tree-map-nodes79610 Ref: -tree-reduce80474 Ref: -tree-reduce-from81356 Ref: -tree-mapreduce81956 Ref: -tree-mapreduce-from82815 Ref: -clone84100 Node: Threading macros84427 Ref: ->84652 Ref: ->>85140 Ref: -->85643 Ref: -as->86199 Ref: -some->86653 Ref: -some->>87038 Ref: -some-->87485 Ref: -doto88052 Node: Binding88605 Ref: -when-let88812 Ref: -when-let*89273 Ref: -if-let89802 Ref: -if-let*90168 Ref: -let90791 Ref: -let*96881 Ref: -lambda97818 Ref: -setq98624 Node: Side effects99425 Ref: -each99619 Ref: -each-while100146 Ref: -each-indexed100766 Ref: -each-r101358 Ref: -each-r-while101800 Ref: -dotimes102444 Node: Destructive operations102997 Ref: !cons103215 Ref: !cdr103419 Node: Function combinators103612 Ref: -partial103816 Ref: -rpartial104334 Ref: -juxt104982 Ref: -compose105434 Ref: -applify106041 Ref: -on106471 Ref: -flip107243 Ref: -rotate-args107767 Ref: -const108396 Ref: -cut108738 Ref: -not109218 Ref: -orfn109762 Ref: -andfn110555 Ref: -iteratefn111342 Ref: -fixfn112044 Ref: -prodfn113618 Node: Development114769 Node: Contribute115058 Node: Contributors116070 Node: FDL118163 Node: GPL143483 Node: Index181232  End Tag Table  Local Variables: coding: utf-8 End: