;;; dash.el --- A modern list library for Emacs ;; Copyright (C) 2012 Magnar Sveen ;; Author: Magnar Sveen ;; Version: 2.7.0 ;; Keywords: lists ;; 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 . ;;; Commentary: ;; A modern list api for Emacs. ;; ;; See documentation on https://github.com/magnars/dash.el#functions ;;; Code: (defgroup dash () "Customize group for dash.el" :group 'lisp :prefix "dash-") (defun dash--enable-fontlock (symbol value) (when value (dash-enable-font-lock)) (set-default symbol value)) (defcustom dash-enable-fontlock nil "If non-nil, enable fontification of dash functions, macros and special values." :type 'boolean :set 'dash--enable-fontlock :group 'dash) (defmacro !cons (car cdr) "Destructive: Set CDR to the cons of CAR and CDR." `(setq ,cdr (cons ,car ,cdr))) (defmacro !cdr (list) "Destructive: Set LIST to the cdr of LIST." `(setq ,list (cdr ,list))) (defmacro --each (list &rest body) "Anaphoric form of `-each'." (declare (debug (form body)) (indent 1)) (let ((l (make-symbol "list"))) `(let ((,l ,list) (it-index 0)) (while ,l (let ((it (car ,l))) ,@body) (setq it-index (1+ it-index)) (!cdr ,l))))) (defun -each (list fn) "Call FN with every item in LIST. Return nil, used for side-effects only." (--each list (funcall fn it))) (put '-each 'lisp-indent-function 1) (defmacro --each-while (list pred &rest body) "Anaphoric form of `-each-while'." (declare (debug (form form body)) (indent 2)) (let ((l (make-symbol "list")) (c (make-symbol "continue"))) `(let ((,l ,list) (,c t) (it-index 0)) (while (and ,l ,c) (let ((it (car ,l))) (if (not ,pred) (setq ,c nil) ,@body)) (setq it-index (1+ it-index)) (!cdr ,l))))) (defun -each-while (list pred fn) "Call FN with every item in LIST while (PRED item) is non-nil. Return nil, used for side-effects only." (--each-while list (funcall pred it) (funcall fn it))) (put '-each-while 'lisp-indent-function 2) (defmacro --dotimes (num &rest body) "Repeatedly executes BODY (presumably for side-effects) with `it` bound to integers from 0 through NUM-1." (declare (debug (form body)) (indent 1)) (let ((n (make-symbol "num"))) `(let ((,n ,num) (it 0)) (while (< it ,n) ,@body (setq it (1+ it)))))) (defun -dotimes (num fn) "Repeatedly calls FN (presumably for side-effects) passing in integers from 0 through NUM-1." (--dotimes num (funcall fn it))) (put '-dotimes 'lisp-indent-function 1) (defun -map (fn list) "Return a new list consisting of the result of applying FN to the items in LIST." (mapcar fn list)) (defmacro --map (form list) "Anaphoric form of `-map'." (declare (debug (form form))) `(mapcar (lambda (it) ,form) ,list)) (defmacro --reduce-from (form initial-value list) "Anaphoric form of `-reduce-from'." (declare (debug (form form form))) `(let ((acc ,initial-value)) (--each ,list (setq acc ,form)) acc)) (defun -reduce-from (fn initial-value list) "Return the result of applying FN to INITIAL-VALUE and the first item in LIST, then applying FN to that result and the 2nd item, etc. If LIST contains no items, return INITIAL-VALUE and FN is not called. In the anaphoric form `--reduce-from', the accumulated value is exposed as `acc`." (--reduce-from (funcall fn acc it) initial-value list)) (defmacro --reduce (form list) "Anaphoric form of `-reduce'." (declare (debug (form form))) (let ((lv (make-symbol "list-value"))) `(let ((,lv ,list)) (if ,lv (--reduce-from ,form (car ,lv) (cdr ,lv)) (let (acc it) ,form))))) (defun -reduce (fn list) "Return the result of applying FN to the first 2 items in LIST, then applying FN to that result and the 3rd item, etc. If LIST contains no items, FN must accept no arguments as well, and reduce return the result of calling FN with no arguments. If LIST has only 1 item, it is returned and FN is not called. In the anaphoric form `--reduce', the accumulated value is exposed as `acc`." (if list (-reduce-from fn (car list) (cdr list)) (funcall fn))) (defun -reduce-r-from (fn initial-value list) "Replace conses with FN, nil with INITIAL-VALUE and evaluate the resulting expression. If LIST is empty, INITIAL-VALUE is returned and FN is not called. Note: this function works the same as `-reduce-from' but the operation associates from right instead of from left." (if (not list) initial-value (funcall fn (car list) (-reduce-r-from fn initial-value (cdr list))))) (defmacro --reduce-r-from (form initial-value list) "Anaphoric version of `-reduce-r-from'." (declare (debug (form form form))) `(-reduce-r-from (lambda (&optional it acc) ,form) ,initial-value ,list)) (defun -reduce-r (fn list) "Replace conses with FN and evaluate the resulting expression. The final nil is ignored. If LIST contains no items, FN must accept no arguments as well, and reduce return the result of calling FN with no arguments. If LIST has only 1 item, it is returned and FN is not called. The first argument of FN is the new item, the second is the accumulated value. Note: this function works the same as `-reduce' but the operation associates from right instead of from left." (cond ((not list) (funcall fn)) ((not (cdr list)) (car list)) (t (funcall fn (car list) (-reduce-r fn (cdr list)))))) (defmacro --reduce-r (form list) "Anaphoric version of `-reduce-r'." (declare (debug (form form))) `(-reduce-r (lambda (&optional it acc) ,form) ,list)) (defmacro --filter (form list) "Anaphoric form of `-filter'." (declare (debug (form form))) (let ((r (make-symbol "result"))) `(let (,r) (--each ,list (when ,form (!cons it ,r))) (nreverse ,r)))) (defun -filter (pred list) "Return a new list of the items in LIST for which PRED returns a non-nil value. Alias: `-select'" (--filter (funcall pred it) list)) (defalias '-select '-filter) (defalias '--select '--filter) (defmacro --remove (form list) "Anaphoric form of `-remove'." (declare (debug (form form))) `(--filter (not ,form) ,list)) (defun -remove (pred list) "Return a new list of the items in LIST for which PRED returns nil. Alias: `-reject'" (--remove (funcall pred it) list)) (defalias '-reject '-remove) (defalias '--reject '--remove) (defmacro --keep (form list) "Anaphoric form of `-keep'." (declare (debug (form form))) (let ((r (make-symbol "result")) (m (make-symbol "mapped"))) `(let (,r) (--each ,list (let ((,m ,form)) (when ,m (!cons ,m ,r)))) (nreverse ,r)))) (defun -keep (fn list) "Return a new list of the non-nil results of applying FN to the items in LIST." (--keep (funcall fn it) list)) (defmacro --map-indexed (form list) "Anaphoric form of `-map-indexed'." (declare (debug (form form))) (let ((r (make-symbol "result"))) `(let (,r) (--each ,list (!cons ,form ,r)) (nreverse ,r)))) (defun -map-indexed (fn list) "Return a new list consisting of the result of (FN index item) for each item in LIST. In the anaphoric form `--map-indexed', the index is exposed as `it-index`." (--map-indexed (funcall fn it-index it) list)) (defmacro --map-when (pred rep list) "Anaphoric form of `-map-when'." (declare (debug (form form form))) (let ((r (make-symbol "result"))) `(let (,r) (--each ,list (!cons (if ,pred ,rep it) ,r)) (nreverse ,r)))) (defun -map-when (pred rep list) "Return a new list where the elements in LIST that does not match the PRED function are unchanged, and where the elements in LIST that do match the PRED function are mapped through the REP function. Alias: `-replace-where' See also: `-update-at'" (--map-when (funcall pred it) (funcall rep it) list)) (defalias '-replace-where '-map-when) (defalias '--replace-where '--map-when) (defun -replace (old new list) "Replace all OLD items in LIST with NEW. Elements are compared using `equal'. See also: `-replace-at'" (--map-when (equal it old) new list)) (defun -flatten (l) "Take a nested list L and return its contents as a single, flat list. See also: `-flatten-n'" (if (and (listp l) (listp (cdr l))) (-mapcat '-flatten l) (list l))) (defun -flatten-n (num list) "Flatten NUM levels of a nested LIST. See also: `-flatten'" (-last-item (--iterate (--mapcat (-list it) it) list (1+ num)))) (defun -concat (&rest lists) "Return a new list with the concatenation of the elements in the supplied LISTS." (apply 'append lists)) (defmacro --mapcat (form list) "Anaphoric form of `-mapcat'." (declare (debug (form form))) `(apply 'append (--map ,form ,list))) (defun -mapcat (fn list) "Return the concatenation of the result of mapping FN over LIST. Thus function FN should return a list." (--mapcat (funcall fn it) list)) (defun -splice (pred fun list) "Splice lists generated by FUN in place of elements matching PRED in LIST. FUN takes the element matching PRED as input. This function can be used as replacement for `,@' in case you need to splice several lists at marked positions (for example with keywords). See also: `-splice-list', `-insert-at'" (let (r) (--each list (if (funcall pred it) (let ((new (funcall fun it))) (--each new (!cons it r))) (!cons it r))) (nreverse r))) (defmacro --splice (pred form list) "Anaphoric form of `-splice'." `(-splice (lambda (it) ,pred) (lambda (it) ,form) ,list)) (defun -splice-list (pred new-list list) "Splice NEW-LIST in place of elements matching PRED in LIST. See also: `-splice', `-insert-at'" (-splice pred (lambda (_) new-list) list)) (defun --splice-list (pred new-list list) "Anaphoric form of `-splice-list'." `(-splice-list (lambda (it) ,pred) ,new-list ,list)) (defun -cons* (&rest args) "Make a new list from the elements of ARGS. The last 2 members of ARGS are used as the final cons of the result so if the final member of ARGS is not a list the result is a dotted list." (-reduce-r 'cons args)) (defun -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 ELEMENTS is non nil, append these to the list as well." (-concat list (list elem) elements)) (defmacro --first (form list) "Anaphoric form of `-first'." (declare (debug (form form))) (let ((n (make-symbol "needle"))) `(let (,n) (--each-while ,list (not ,n) (when ,form (setq ,n it))) ,n))) (defun -first (pred list) "Return the first x in LIST where (PRED x) is non-nil, else nil. To get the first item in the list no questions asked, use `car'. Alias: `-find'" (--first (funcall pred it) list)) (defalias '-find '-first) (defalias '--find '--first) (defmacro --last (form list) "Anaphoric form of `-last'." (declare (debug (form form))) (let ((n (make-symbol "needle"))) `(let (,n) (--each ,list (when ,form (setq ,n it))) ,n))) (defun -last (pred list) "Return the last x in LIST where (PRED x) is non-nil, else nil." (--last (funcall pred it) list)) (defalias '-first-item 'car "Return the first item of LIST, or nil on an empty list.") (defun -last-item (list) "Return the last item of LIST, or nil on an empty list." (car (last list))) (defmacro --count (pred list) "Anaphoric form of `-count'." (declare (debug (form form))) (let ((r (make-symbol "result"))) `(let ((,r 0)) (--each ,list (when ,pred (setq ,r (1+ ,r)))) ,r))) (defun -count (pred list) "Counts the number of items in LIST where (PRED item) is non-nil." (--count (funcall pred it) list)) (defun ---truthy? (val) (not (null val))) (defmacro --any? (form list) "Anaphoric form of `-any?'." (declare (debug (form form))) `(---truthy? (--first ,form ,list))) (defun -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? (funcall pred it) list)) (defalias '-some? '-any?) (defalias '--some? '--any?) (defalias '-any-p '-any?) (defalias '--any-p '--any?) (defalias '-some-p '-any?) (defalias '--some-p '--any?) (defmacro --all? (form list) "Anaphoric form of `-all?'." (declare (debug (form form))) (let ((a (make-symbol "all"))) `(let ((,a t)) (--each-while ,list ,a (setq ,a ,form)) (---truthy? ,a)))) (defun -all? (pred list) "Return t if (PRED x) is non-nil for all x in LIST, else nil. Alias: `-all-p', `-every?', `-every-p'" (--all? (funcall pred it) list)) (defalias '-every? '-all?) (defalias '--every? '--all?) (defalias '-all-p '-all?) (defalias '--all-p '--all?) (defalias '-every-p '-all?) (defalias '--every-p '--all?) (defmacro --none? (form list) "Anaphoric form of `-none?'." (declare (debug (form form))) `(--all? (not ,form) ,list)) (defun -none? (pred list) "Return t if (PRED x) is nil for all x in LIST, else nil. Alias: `-none-p'" (--none? (funcall pred it) list)) (defalias '-none-p '-none?) (defalias '--none-p '--none?) (defmacro --only-some? (form list) "Anaphoric form of `-only-some?'." (declare (debug (form form))) (let ((y (make-symbol "yes")) (n (make-symbol "no"))) `(let (,y ,n) (--each-while ,list (not (and ,y ,n)) (if ,form (setq ,y t) (setq ,n t))) (---truthy? (and ,y ,n))))) (defun -only-some? (pred list) "Return `t` if at least one item of LIST matches PRED and at least one item of LIST does not match PRED. Return `nil` both if all items match the predicate or if none of the items match the predicate. Alias: `-only-some-p'" (--only-some? (funcall pred it) list)) (defalias '-only-some-p '-only-some?) (defalias '--only-some-p '--only-some?) (defun -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." (let ((length (length list)) (new-list nil)) ;; to defaults to the end of the list (setq to (or to length)) (setq step (or step 1)) ;; handle negative indices (when (< from 0) (setq from (mod from length))) (when (< to 0) (setq to (mod to length))) ;; iterate through the list, keeping the elements we want (--each-while list (< it-index to) (when (and (>= it-index from) (= (mod (- from it-index) step) 0)) (push it new-list))) (nreverse new-list))) (defun -take (n list) "Return a new list of the first N items in LIST, or all items if there are fewer than N." (let (result) (--dotimes n (when list (!cons (car list) result) (!cdr list))) (nreverse result))) (defalias '-drop 'nthcdr "Return the tail of LIST without the first N items.") (defmacro --take-while (form list) "Anaphoric form of `-take-while'." (declare (debug (form form))) (let ((r (make-symbol "result"))) `(let (,r) (--each-while ,list ,form (!cons it ,r)) (nreverse ,r)))) (defun -take-while (pred list) "Return a new list of successive items from LIST while (PRED item) returns a non-nil value." (--take-while (funcall pred it) list)) (defmacro --drop-while (form list) "Anaphoric form of `-drop-while'." (declare (debug (form form))) (let ((l (make-symbol "list"))) `(let ((,l ,list)) (while (and ,l (let ((it (car ,l))) ,form)) (!cdr ,l)) ,l))) (defun -drop-while (pred list) "Return the tail of LIST starting from the first item for which (PRED item) returns nil." (--drop-while (funcall pred it) list)) (defun -split-at (n list) "Return a list of ((-take N LIST) (-drop N LIST)), in no more than one pass through the list." (let (result) (--dotimes n (when list (!cons (car list) result) (!cdr list))) (list (nreverse result) list))) (defun -rotate (n list) "Rotate LIST N places to the right. With N negative, rotate to the left. The time complexity is O(n)." (if (> n 0) (append (last list n) (butlast list n)) (append (-drop (- n) list) (-take (- n) list)))) (defun -insert-at (n x list) "Return a list with X inserted into LIST at position N. See also: `-splice', `-splice-list'" (let ((split-list (-split-at n list))) (nconc (car split-list) (cons x (cadr split-list))))) (defun -replace-at (n x list) "Return a list with element at Nth position in LIST replaced with X. See also: `-replace'" (let ((split-list (-split-at n list))) (nconc (car split-list) (cons x (cdr (cadr split-list)))))) (defun -update-at (n func list) "Return a list with element at Nth position in LIST replaced with `(func (nth n list))`. See also: `-map-when'" (let ((split-list (-split-at n list))) (nconc (car split-list) (cons (funcall func (car (cadr split-list))) (cdr (cadr split-list)))))) (defmacro --update-at (n form list) "Anaphoric version of `-update-at'." (declare (debug (form form form))) `(-update-at ,n (lambda (it) ,form) ,list)) (defun -remove-at (n list) "Return a list with element at Nth position in LIST removed. See also: `-remove-at-indices', `-remove'" (-remove-at-indices (list n) list)) (defun -remove-at-indices (indices list) "Return a list whose elements are elements from LIST without elements selected as `(nth i list)` for all i from INDICES. See also: `-remove-at', `-remove'" (let* ((indices (-sort '< indices)) (diffs (cons (car indices) (-map '1- (-zip-with '- (cdr indices) indices)))) r) (--each diffs (let ((split (-split-at it list))) (!cons (car split) r) (setq list (cdr (cadr split))))) (!cons list r) (apply '-concat (nreverse r)))) (defmacro --split-with (pred list) "Anaphoric form of `-split-with'." (declare (debug (form form))) (let ((l (make-symbol "list")) (r (make-symbol "result")) (c (make-symbol "continue"))) `(let ((,l ,list) (,r nil) (,c t)) (while (and ,l ,c) (let ((it (car ,l))) (if (not ,pred) (setq ,c nil) (!cons it ,r) (!cdr ,l)))) (list (nreverse ,r) ,l)))) (defun -split-with (pred list) "Return a list of ((-take-while PRED LIST) (-drop-while PRED LIST)), in no more than one pass through the list." (--split-with (funcall pred it) list)) (defmacro -split-on (item list) "Split the LIST each time ITEM is found. Unlike `-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'" (declare (debug (form form))) `(-split-when (lambda (it) (equal it ,item)) ,list)) (defmacro --split-when (form list) "Anaphoric version of `-split-when'." (declare (debug (form form))) `(-split-when (lambda (it) ,form) ,list)) (defun -split-when (fn list) "Split the LIST on each element where FN returns non-nil. Unlike `-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'." (let (r s) (while list (if (not (funcall fn (car list))) (push (car list) s) (when s (push (nreverse s) r)) (setq s nil)) (!cdr list)) (when s (push (nreverse s) r)) (nreverse r))) (defmacro --separate (form list) "Anaphoric form of `-separate'." (declare (debug (form form))) (let ((y (make-symbol "yes")) (n (make-symbol "no"))) `(let (,y ,n) (--each ,list (if ,form (!cons it ,y) (!cons it ,n))) (list (nreverse ,y) (nreverse ,n))))) (defun -separate (pred list) "Return a list of ((-filter PRED LIST) (-remove PRED LIST)), in one pass through the list." (--separate (funcall pred it) list)) (defun ---partition-all-in-steps-reversed (n step list) "Private: Used by -partition-all-in-steps and -partition-in-steps." (when (< step 1) (error "Step must be a positive number, or you're looking at some juicy infinite loops.")) (let ((result nil) (len 0)) (while list (!cons (-take n list) result) (setq list (-drop step list))) result)) (defun -partition-all-in-steps (n step list) "Return a new list with the items in LIST grouped into N-sized sublists at offsets STEP apart. The last groups may contain less than N items." (nreverse (---partition-all-in-steps-reversed n step list))) (defun -partition-in-steps (n step list) "Return a new list with the items in LIST grouped into N-sized sublists at offsets STEP apart. If there are not enough items to make the last group N-sized, those items are discarded." (let ((result (---partition-all-in-steps-reversed n step list))) (while (and result (< (length (car result)) n)) (!cdr result)) (nreverse result))) (defun -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-in-steps n n list)) (defun -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-in-steps n n list)) (defmacro --partition-by (form list) "Anaphoric form of `-partition-by'." (declare (debug (form form))) (let ((r (make-symbol "result")) (s (make-symbol "sublist")) (v (make-symbol "value")) (n (make-symbol "new-value")) (l (make-symbol "list"))) `(let ((,l ,list)) (when ,l (let* ((,r nil) (it (car ,l)) (,s (list it)) (,v ,form) (,l (cdr ,l))) (while ,l (let* ((it (car ,l)) (,n ,form)) (unless (equal ,v ,n) (!cons (nreverse ,s) ,r) (setq ,s nil) (setq ,v ,n)) (!cons it ,s) (!cdr ,l))) (!cons (nreverse ,s) ,r) (nreverse ,r)))))) (defun -partition-by (fn list) "Apply FN to each item in LIST, splitting it each time FN returns a new value." (--partition-by (funcall fn it) list)) (defmacro --partition-by-header (form list) "Anaphoric form of `-partition-by-header'." (declare (debug (form form))) (let ((r (make-symbol "result")) (s (make-symbol "sublist")) (h (make-symbol "header-value")) (b (make-symbol "seen-body?")) (n (make-symbol "new-value")) (l (make-symbol "list"))) `(let ((,l ,list)) (when ,l (let* ((,r nil) (it (car ,l)) (,s (list it)) (,h ,form) (,b nil) (,l (cdr ,l))) (while ,l (let* ((it (car ,l)) (,n ,form)) (if (equal ,h ,n) (when ,b (!cons (nreverse ,s) ,r) (setq ,s nil) (setq ,b nil)) (setq ,b t)) (!cons it ,s) (!cdr ,l))) (!cons (nreverse ,s) ,r) (nreverse ,r)))))) (defun -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 (funcall fn it) list)) (defmacro --group-by (form list) "Anaphoric form of `-group-by'." (declare (debug (form form))) (let ((l (make-symbol "list")) (v (make-symbol "value")) (k (make-symbol "key")) (r (make-symbol "result"))) `(let ((,l ,list) ,r) ;; Convert `list' to an alist and store it in `r'. (while ,l (let* ((,v (car ,l)) (it ,v) (,k ,form) (kv (assoc ,k ,r))) (if kv (setcdr kv (cons ,v (cdr kv))) (push (list ,k ,v) ,r)) (setq ,l (cdr ,l)))) ;; Reverse lists in each group. (let ((rest ,r)) (while rest (let ((kv (car rest))) (setcdr kv (nreverse (cdr kv)))) (setq rest (cdr rest)))) ;; Reverse order of keys. (nreverse ,r)))) (defun -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 (funcall fn it) list)) (defun -interpose (sep list) "Return a new list of all elements in LIST separated by SEP." (let (result) (when list (!cons (car list) result) (!cdr list)) (while list (setq result (cons (car list) (cons sep result))) (!cdr list)) (nreverse result))) (defun -interleave (&rest lists) "Return a new list of the first item in each list, then the second etc." (let (result) (while (-none? 'null lists) (--each lists (!cons (car it) result)) (setq lists (-map 'cdr lists))) (nreverse result))) (defmacro --zip-with (form list1 list2) "Anaphoric form of `-zip-with'. The elements in list1 is bound as `it`, the elements in list2 as `other`." (declare (debug (form form form))) (let ((r (make-symbol "result")) (l1 (make-symbol "list1")) (l2 (make-symbol "list2"))) `(let ((,r nil) (,l1 ,list1) (,l2 ,list2)) (while (and ,l1 ,l2) (let ((it (car ,l1)) (other (car ,l2))) (!cons ,form ,r) (!cdr ,l1) (!cdr ,l2))) (nreverse ,r)))) (defun -zip-with (fn list1 list2) "Zip the two lists LIST1 and LIST2 using a function FN. This function is applied pairwise taking as first argument element of LIST1 and as second argument element of LIST2 at corresponding position. The anaphoric form `--zip-with' binds the elements from LIST1 as `it`, and the elements from LIST2 as `other`." (--zip-with (funcall fn it other) list1 list2)) (defun -zip (&rest lists) "Zip LISTS together. Group the head of each list, followed by the second elements of each list, and so on. The lengths of the returned groupings are equal to the length of the shortest input list. If two lists are provided as arguments, return the groupings as a list of cons cells. Otherwise, return the groupings as a list of lists. " (let (results) (while (-none? 'null lists) (setq results (cons (mapcar 'car lists) results)) (setq lists (mapcar 'cdr lists))) (setq results (nreverse results)) (if (= (length lists) 2) ; to support backward compatability, return ; a cons cell if two lists were provided (--map (cons (car it) (cadr it)) results) results))) (defun -zip-fill (fill-value &rest lists) "Zip LISTS, with FILL-VALUE padded onto the shorter lists. The lengths of the returned groupings are equal to the length of the longest input list." (apply '-zip (apply '-pad (cons fill-value lists)))) (defun -cycle (list) "Return an infinite copy of LIST that will cycle through the elements and repeat from the beginning." (let ((newlist (-map 'identity list))) (nconc newlist newlist))) (defun -pad (fill-value &rest lists) "Appends FILL-VALUE to the end of each list in LISTS such that they will all have the same length." (let* ((annotations (-annotate 'length lists)) (n (-max (-map 'car annotations)))) (--map (append (cdr it) (-repeat (- n (car it)) fill-value)) annotations))) (defun -annotate (fn list) "Return a list of cons cells where each cell is FN applied to each element of LIST paired with the unmodified element of LIST." (-zip (-map fn list) list)) (defmacro --annotate (form list) "Anaphoric version of `-annotate'." (declare (debug (form form))) `(-annotate (lambda (it) ,form) ,list)) (defun dash--table-carry (lists restore-lists &optional re) "Helper for `-table' and `-table-flat'. If a list overflows, carry to the right and reset the list. Return how many lists were re-seted." (while (and (not (car lists)) (not (equal lists '(nil)))) (setcar lists (car restore-lists)) (pop (cadr lists)) (!cdr lists) (!cdr restore-lists) (when re (push (nreverse (car re)) (cadr re)) (setcar re nil) (!cdr re)))) (defun -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'" (let ((restore-lists (copy-sequence lists)) (last-list (last lists)) (re (--map nil (number-sequence 1 (length lists))))) (while (car last-list) (let ((item (apply fn (-map 'car lists)))) (push item (car re)) (pop (car lists)) (dash--table-carry lists restore-lists re))) (nreverse (car (last re))))) (defun -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)) (-table fn lists)) but the implementation here is much more efficient. See also: `-flatten-n', `-table'" (let ((restore-lists (copy-sequence lists)) (last-list (last lists)) re) (while (car last-list) (push (apply fn (-map 'car lists)) re) (pop (car lists)) (dash--table-carry lists restore-lists)) (nreverse re))) (defun -partial (fn &rest args) "Take a function FN and fewer than the normal arguments to FN, and return a fn that takes a variable number of additional ARGS. When called, the returned function calls FN with ARGS first and then additional args." (apply 'apply-partially fn args)) (defun -elem-index (elem list) "Return the index of the first element in the given LIST which is equal to the query element ELEM, or nil if there is no such element." (car (-elem-indices elem list))) (defun -elem-indices (elem list) "Return the indices of all elements in LIST equal to the query element ELEM, in ascending order." (-find-indices (-partial 'equal elem) list)) (defun -find-indices (pred list) "Return the indices of all elements in LIST satisfying the predicate PRED, in ascending order." (let ((i 0)) (apply 'append (--map-indexed (when (funcall pred it) (list it-index)) list)))) (defmacro --find-indices (form list) "Anaphoric version of `-find-indices'." (declare (debug (form form))) `(-find-indices (lambda (it) ,form) ,list)) (defun -find-index (pred list) "Take a predicate PRED and a LIST and return the index of the first element in the list satisfying the predicate, or nil if there is no such element." (car (-find-indices pred list))) (defmacro --find-index (form list) "Anaphoric version of `-find-index'." (declare (debug (form form))) `(-find-index (lambda (it) ,form) ,list)) (defun -find-last-index (pred list) "Take a predicate PRED and a LIST and return the index of the last element in the list satisfying the predicate, or nil if there is no such element." (-last-item (-find-indices pred list))) (defmacro --find-last-index (form list) "Anaphoric version of `-find-last-index'." `(-find-last-index (lambda (it) ,form) ,list)) (defun -select-by-indices (indices list) "Return a list whose elements are elements from LIST selected as `(nth i list)` for all i from INDICES." (let (r) (--each indices (!cons (nth it list) r)) (nreverse r))) (defmacro -> (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." (cond ((null form) x) ((null more) (if (listp form) `(,(car form) ,x ,@(cdr form)) (list form x))) (:else `(-> (-> ,x ,form) ,@more)))) (defmacro ->> (x 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." (if (null more) (if (listp form) `(,(car form) ,@(cdr form) ,x) (list form x)) `(->> (->> ,x ,form) ,@more))) (defmacro --> (x form &rest more) "Thread the expr through the forms. Insert X at the position signified by the token `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." (if (null more) (if (listp form) (--map-when (eq it 'it) x form) (list form x)) `(--> (--> ,x ,form) ,@more))) (put '-> 'lisp-indent-function 1) (put '->> 'lisp-indent-function 1) (put '--> 'lisp-indent-function 1) (defun -grade-up (comparator list) "Grade elements of LIST using COMPARATOR relation, yielding a permutation vector such that applying this permutation to LIST sorts it in ascending order." ;; ugly hack to "fix" lack of lexical scope (let ((comp `(lambda (it other) (funcall ',comparator (car it) (car other))))) (->> (--map-indexed (cons it it-index) list) (-sort comp) (-map 'cdr)))) (defun -grade-down (comparator list) "Grade elements of LIST using COMPARATOR relation, yielding a permutation vector such that applying this permutation to LIST sorts it in descending order." ;; ugly hack to "fix" lack of lexical scope (let ((comp `(lambda (it other) (funcall ',comparator (car other) (car it))))) (->> (--map-indexed (cons it it-index) list) (-sort comp) (-map 'cdr)))) (defmacro -when-let (var-val &rest body) "If VAL evaluates to non-nil, bind it to VAR and execute body. VAR-VAL should be a (VAR VAL) pair." (declare (debug ((symbolp form) body)) (indent 1)) (let ((var (car var-val)) (val (cadr var-val))) `(let ((,var ,val)) (when ,var ,@body)))) (defmacro -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 (corresponding to bindings of `let*')." (declare (debug ((&rest (symbolp form)) body)) (indent 1)) (if (= (length vars-vals) 1) `(-when-let ,(car vars-vals) ,@body) `(-when-let ,(car vars-vals) (-when-let* ,(cdr vars-vals) ,@body)))) (defmacro --when-let (val &rest body) "If VAL evaluates to non-nil, bind it to `it' and execute body." (declare (debug (form body)) (indent 1)) `(let ((it ,val)) (when it ,@body))) (defmacro -if-let (var-val then &rest else) "If VAL evaluates to non-nil, bind it to VAR and do THEN, otherwise do ELSE. VAR-VAL should be a (VAR VAL) pair." (declare (debug ((symbolp form) form body)) (indent 2)) (let ((var (car var-val)) (val (cadr var-val))) `(let ((,var ,val)) (if ,var ,then ,@else)))) (defmacro -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 (corresponding to the bindings of `let*')." (declare (debug ((&rest (symbolp form)) form body)) (indent 2)) (let ((first-pair (car vars-vals)) (rest (cdr vars-vals))) (if (= (length vars-vals) 1) `(-if-let ,first-pair ,then ,@else) `(-if-let ,first-pair (-if-let* ,rest ,then ,@else) ,@else)))) (defmacro --if-let (val then &rest else) "If VAL evaluates to non-nil, bind it to `it' and do THEN, otherwise do ELSE." (declare (debug (form form body)) (indent 2)) `(let ((it ,val)) (if it ,then ,@else))) (defun -distinct (list) "Return a new list with all duplicates removed. The test for equality is done with `equal', or with `-compare-fn' if that's non-nil. Alias: `-uniq'" (let (result) (--each list (unless (-contains? result it) (!cons it result))) (nreverse result))) (defalias '-uniq '-distinct) (defun -union (list list2) "Return a new list containing the elements of LIST1 and elements of LIST2 that are not in LIST1. The test for equality is done with `equal', or with `-compare-fn' if that's non-nil." (let (result) (--each list (!cons it result)) (--each list2 (unless (-contains? result it) (!cons it result))) (nreverse result))) (defun -intersection (list list2) "Return a new list containing only the elements that are members of both LIST and LIST2. The test for equality is done with `equal', or with `-compare-fn' if that's non-nil." (--filter (-contains? list2 it) list)) (defun -difference (list list2) "Return a new list with only the members of LIST that are not in LIST2. The test for equality is done with `equal', or with `-compare-fn' if that's non-nil." (--filter (not (-contains? list2 it)) list)) (defvar -compare-fn nil "Tests for equality use this function or `equal' if this is nil. It should only be set using dynamic scope with a let, like: (let ((-compare-fn =)) (-union numbers1 numbers2 numbers3)") (defun -contains? (list element) "Return non-nil if LIST contains ELEMENT. The test for equality is done with `equal', or with `-compare-fn' if that's non-nil. Alias: `-contains-p'" (not (null (cond ((null -compare-fn) (member element list)) ((eq -compare-fn 'eq) (memq element list)) ((eq -compare-fn 'eql) (memql element list)) (t (let ((lst list)) (while (and lst (not (funcall -compare-fn element (car lst)))) (setq lst (cdr lst))) lst)))))) (defalias '-contains-p '-contains?) (defun -same-items? (list list2) "Return true if LIST and LIST2 has the same items. The order of the elements in the lists does not matter. Alias: `-same-items-p'" (let ((length-a (length list)) (length-b (length list2))) (and (= length-a length-b) (= length-a (length (-intersection list list2)))))) (defalias '-same-items-p '-same-items?) (defun -is-prefix? (prefix list) "Return non-nil if PREFIX is prefix of LIST. Alias: `-is-prefix-p'" (--each-while list (equal (car prefix) it) (!cdr prefix)) (not prefix)) (defun -is-suffix? (suffix list) "Return non-nil if SUFFIX is suffix of LIST. Alias: `-is-suffix-p'" (-is-prefix? (nreverse suffix) (nreverse list))) (defun -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'" (let (done) (while (and (not done) list) (setq done (-is-prefix? infix list)) (!cdr list)) done)) (defalias '-is-prefix-p '-is-prefix?) (defalias '-is-suffix-p '-is-suffix?) (defalias '-is-infix-p '-is-infix?) (defun -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 (copy-sequence list) comparator)) (defmacro --sort (form list) "Anaphoric form of `-sort'." (declare (debug (form form))) `(-sort (lambda (it other) ,form) ,list)) (defun -list (&rest args) "Return a list with ARGS. If first item of ARGS is already a list, simply return ARGS. If not, return a list with ARGS as elements." (let ((arg (car args))) (if (listp arg) arg args))) (defun -repeat (n x) "Return a list with X repeated N times. Return nil if N is less than 1." (let (ret) (--dotimes n (!cons x ret)) ret)) (defun -sum (list) "Return the sum of LIST." (apply '+ list)) (defun -product (list) "Return the product of LIST." (apply '* list)) (defun -max (list) "Return the largest value from LIST of numbers or markers." (apply 'max list)) (defun -min (list) "Return the smallest value from LIST of numbers or markers." (apply 'min list)) (defun -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' which can transform the values before comparing them." (--reduce (if (funcall comparator it acc) it acc) list)) (defun -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' which can transform the values before comparing them." (--reduce (if (funcall comparator it acc) acc it) list)) (defmacro --max-by (form list) "Anaphoric version of `-max-by'. The items for the comparator form are exposed as \"it\" and \"other\"." (declare (debug (form form))) `(-max-by (lambda (it other) ,form) ,list)) (defmacro --min-by (form list) "Anaphoric version of `-min-by'. The items for the comparator form are exposed as \"it\" and \"other\"." (declare (debug (form form))) `(-min-by (lambda (it other) ,form) ,list)) (defun -iterate (fun init n) "Return a list of iterated applications of FUN to INIT. This means a list of form: (init (fun init) (fun (fun init)) ...) N is the length of the returned list." (if (= n 0) nil (let ((r (list init))) (--dotimes (1- n) (push (funcall fun (car r)) r)) (nreverse r)))) (defmacro --iterate (form init n) "Anaphoric version of `-iterate'." (declare (debug (form form form))) `(-iterate (lambda (it) ,form) ,init ,n)) (defun -unfold (fun seed) "Build a list from SEED using FUN. This is \"dual\" operation to `-reduce-r': while -reduce-r consumes a list to produce a single value, `-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." (let ((last (funcall fun seed)) r) (while last (push (car last) r) (setq last (funcall fun (cdr last)))) (nreverse r))) (defmacro --unfold (form seed) "Anaphoric version of `-unfold'." (declare (debug (form form))) `(-unfold (lambda (it) ,form) ,seed)) (defun -cons-pair? (con) "Return non-nil if CON is true cons pair. That is (A . B) where B is not a list." (and (listp con) (not (listp (cdr con))))) (defun -cons-to-list (con) "Convert a cons pair to a list with `car' and `cdr' of the pair respectively." (list (car con) (cdr con))) (defun -value-to-list (val) "Convert a value to a list. If the value is a cons pair, make a list with two elements, `car' and `cdr' of the pair respectively. If the value is anything else, wrap it in a list." (cond ((-cons-pair? val) (-cons-to-list val)) (t (list val)))) (defun -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'. This is the same as calling `-tree-reduce-from' after `-tree-map' but is twice as fast as it only traverse the structure once." (cond ((not tree) nil) ((-cons-pair? tree) (funcall fn tree)) ((listp tree) (-reduce-r-from folder init-value (mapcar (lambda (x) (-tree-mapreduce-from fn folder init-value x)) tree))) (t (funcall fn tree)))) (defmacro --tree-mapreduce-from (form folder init-value tree) "Anaphoric form of `-tree-mapreduce-from'." (declare (debug (form form form form))) `(-tree-mapreduce-from (lambda (it) ,form) (lambda (it acc) ,folder) ,init-value ,tree)) (defun -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'. This is the same as calling `-tree-reduce' after `-tree-map' but is twice as fast as it only traverse the structure once." (cond ((not tree) nil) ((-cons-pair? tree) (funcall fn tree)) ((listp tree) (-reduce-r folder (mapcar (lambda (x) (-tree-mapreduce fn folder x)) tree))) (t (funcall fn tree)))) (defmacro --tree-mapreduce (form folder tree) "Anaphoric form of `-tree-mapreduce'." (declare (debug (form form form))) `(-tree-mapreduce (lambda (it) ,form) (lambda (it acc) ,folder) ,tree)) (defun -tree-map (fn tree) "Apply FN to each element of TREE while preserving the tree structure." (cond ((not tree) nil) ((-cons-pair? tree) (funcall fn tree)) ((listp tree) (mapcar (lambda (x) (-tree-map fn x)) tree)) (t (funcall fn tree)))) (defmacro --tree-map (form tree) "Anaphoric form of `-tree-map'." (declare (debug (form form))) `(-tree-map (lambda (it) ,form) ,tree)) (defun -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." (cond ((not tree) nil) ((-cons-pair? tree) tree) ((listp tree) (-reduce-r-from fn init-value (mapcar (lambda (x) (-tree-reduce-from fn init-value x)) tree))) (t tree))) (defmacro --tree-reduce-from (form init-value tree) "Anaphoric form of `-tree-reduce-from'." (declare (debug (form form form))) `(-tree-reduce-from (lambda (it acc) ,form) ,init-value ,tree)) (defun -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' for how exactly are lists of zero or one element handled." (cond ((not tree) nil) ((-cons-pair? tree) tree) ((listp tree) (-reduce-r fn (mapcar (lambda (x) (-tree-reduce fn x)) tree))) (t tree))) (defmacro --tree-reduce (form tree) "Anaphoric form of `-tree-reduce'." (declare (debug (form form))) `(-tree-reduce (lambda (it acc) ,form) ,tree)) (defun -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." (-tree-map 'identity list)) (defun dash-enable-font-lock () "Add syntax highlighting to dash functions, macros and magic values." (eval-after-load "lisp-mode" '(progn (let ((new-keywords '( "-each" "--each" "-each-while" "--each-while" "-dotimes" "--dotimes" "-map" "--map" "-reduce-from" "--reduce-from" "-reduce" "--reduce" "-reduce-r-from" "--reduce-r-from" "-reduce-r" "--reduce-r" "-filter" "--filter" "-select" "--select" "-remove" "--remove" "-reject" "--reject" "-keep" "--keep" "-map-indexed" "--map-indexed" "-splice" "--splice" "-splice-list" "--splice-list" "-map-when" "--map-when" "-replace-where" "--replace-where" "-replace" "-flatten" "-flatten-n" "-concat" "-mapcat" "--mapcat" "-cons*" "-snoc" "-first" "--first" "-find" "--find" "-last" "--last" "-first-item" "-last-item" "-count" "--count" "-any?" "--any?" "-some?" "--some?" "-any-p" "--any-p" "-some-p" "--some-p" "-all?" "--all?" "-every?" "--every?" "-all-p" "--all-p" "-every-p" "--every-p" "-none?" "--none?" "-none-p" "--none-p" "-only-some?" "--only-some?" "-only-some-p" "--only-some-p" "-slice" "-take" "-drop" "-take-while" "--take-while" "-drop-while" "--drop-while" "-split-at" "-rotate" "-insert-at" "-replace-at" "-update-at" "--update-at" "-remove-at" "-remove-at-indices" "-split-with" "--split-with" "-split-on" "-split-when" "--split-when" "-separate" "--separate" "-partition-all-in-steps" "-partition-in-steps" "-partition-all" "-partition" "-partition-by" "--partition-by" "-partition-by-header" "--partition-by-header" "-group-by" "--group-by" "-interpose" "-interleave" "-zip-with" "--zip-with" "-zip" "-zip-fill" "-cycle" "-pad" "-annotate" "--annotate" "-table" "-table-flat" "-partial" "-elem-index" "-elem-indices" "-find-indices" "--find-indices" "-find-index" "--find-index" "-find-last-index" "--find-last-index" "-select-by-indices" "-grade-up" "-grade-down" "->" "->>" "-->" "-when-let" "-when-let*" "--when-let" "-if-let" "-if-let*" "--if-let" "-distinct" "-uniq" "-union" "-intersection" "-difference" "-contains?" "-contains-p" "-same-items?" "-same-items-p" "-is-prefix-p" "-is-prefix?" "-is-suffix-p" "-is-suffix?" "-is-infix-p" "-is-infix?" "-sort" "--sort" "-list" "-repeat" "-sum" "-product" "-max" "-min" "-max-by" "--max-by" "-min-by" "--min-by" "-iterate" "--iterate" "-unfold" "--unfold" "-cons-pair?" "-cons-to-list" "-value-to-list" "-tree-mapreduce-from" "--tree-mapreduce-from" "-tree-mapreduce" "--tree-mapreduce" "-tree-map" "--tree-map" "-tree-reduce-from" "--tree-reduce-from" "-tree-reduce" "--tree-reduce" "-clone" "-rpartial" "-juxt" "-applify" "-on" "-flip" "-const" "-cut" "-orfn" "-andfn" "-iteratefn" "-prodfn" )) (special-variables '( "it" "it-index" "acc" "other" ))) (font-lock-add-keywords 'emacs-lisp-mode `((,(concat "\\_<" (regexp-opt special-variables 'paren) "\\_>") 1 font-lock-variable-name-face)) 'append) (font-lock-add-keywords 'emacs-lisp-mode `((,(concat "(\\s-*" (regexp-opt new-keywords 'paren) "\\_>") 1 font-lock-keyword-face)) 'append)) (--each (buffer-list) (with-current-buffer it (when (and (eq major-mode 'emacs-lisp-mode) (boundp 'font-lock-mode) font-lock-mode) (font-lock-refresh-defaults))))))) (provide 'dash) ;;; dash.el ends here