--- /dev/null
+;;; seq-24.el --- seq.el implementation for Emacs 24.x -*- lexical-binding: t -*-
+
+;; Copyright (C) 2014-2016 Free Software Foundation, Inc.
+
+;; Author: Nicolas Petton <nicolas@petton.fr>
+;; Keywords: sequences
+
+;; Maintainer: emacs-devel@gnu.org
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs 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.
+
+;; GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Sequence-manipulation functions that complement basic functions
+;; provided by subr.el.
+;;
+;; All functions are prefixed with "seq-".
+;;
+;; All provided functions work on lists, strings and vectors.
+;;
+;; Functions taking a predicate or iterating over a sequence using a
+;; function as argument take the function as their first argument and
+;; the sequence as their second argument. All other functions take
+;; the sequence as their first argument.
+
+;;; Code:
+
+(defmacro seq-doseq (spec &rest body)
+ "Loop over a sequence.
+Similar to `dolist' but can be applied to lists, strings, and vectors.
+
+Evaluate BODY with VAR bound to each element of SEQ, in turn.
+
+\(fn (VAR SEQ) BODY...)"
+ (declare (indent 1) (debug ((symbolp form &optional form) body)))
+ (let ((length (make-symbol "length"))
+ (seq (make-symbol "seq"))
+ (index (make-symbol "index")))
+ `(let* ((,seq ,(cadr spec))
+ (,length (if (listp ,seq) nil (seq-length ,seq)))
+ (,index (if ,length 0 ,seq)))
+ (while (if ,length
+ (< ,index ,length)
+ (consp ,index))
+ (let ((,(car spec) (if ,length
+ (prog1 (seq-elt ,seq ,index)
+ (setq ,index (+ ,index 1)))
+ (pop ,index))))
+ ,@body)))))
+
+;; Implementation of `seq-let' compatible with Emacs<25.1.
+(defmacro seq-let (args sequence &rest body)
+ "Bind the variables in ARGS to the elements of SEQUENCE then evaluate BODY.
+
+ARGS can also include the `&rest' marker followed by a variable
+name to be bound to the rest of SEQUENCE."
+ (declare (indent 2) (debug t))
+ (let ((seq-var (make-symbol "seq")))
+ `(let* ((,seq-var ,sequence)
+ ,@(seq--make-bindings args seq-var))
+ ,@body)))
+
+(defun seq-drop (sequence n)
+ "Return a subsequence of SEQUENCE without its first N elements.
+The result is a sequence of the same type as SEQUENCE.
+
+If N is a negative integer or zero, SEQUENCE is returned."
+ (if (<= n 0)
+ sequence
+ (if (listp sequence)
+ (seq--drop-list sequence n)
+ (let ((length (seq-length sequence)))
+ (seq-subseq sequence (min n length) length)))))
+
+(defun seq-take (sequence n)
+ "Return a subsequence of SEQUENCE with its first N elements.
+The result is a sequence of the same type as SEQUENCE.
+
+If N is a negative integer or zero, an empty sequence is
+returned."
+ (if (listp sequence)
+ (seq--take-list sequence n)
+ (seq-subseq sequence 0 (min (max n 0) (seq-length sequence)))))
+
+(defun seq-drop-while (predicate sequence)
+ "Return a sequence from the first element for which (PREDICATE element) is nil in SEQUENCE.
+The result is a sequence of the same type as SEQUENCE."
+ (if (listp sequence)
+ (seq--drop-while-list predicate sequence)
+ (seq-drop sequence (seq--count-successive predicate sequence))))
+
+(defun seq-take-while (predicate sequence)
+ "Return the successive elements for which (PREDICATE element) is non-nil in SEQUENCE.
+The result is a sequence of the same type as SEQUENCE."
+ (if (listp sequence)
+ (seq--take-while-list predicate sequence)
+ (seq-take sequence (seq--count-successive predicate sequence))))
+
+(defun seq-filter (predicate sequence)
+ "Return a list of all the elements for which (PREDICATE element) is non-nil in SEQUENCE."
+ (let ((exclude (make-symbol "exclude")))
+ (delq exclude (seq-map (lambda (elt)
+ (if (funcall predicate elt)
+ elt
+ exclude))
+ sequence))))
+
+(defun seq-map-indexed (function sequence)
+ "Return the result of applying FUNCTION to each element of SEQUENCE.
+Unlike `seq-map', FUNCTION takes two arguments: the element of
+the sequence, and its index within the sequence."
+ (let ((index 0))
+ (seq-map (lambda (elt)
+ (prog1
+ (funcall function elt index)
+ (setq index (1+ index))))
+ sequence)))
+
+(defun seq-remove (predicate sequence)
+ "Return a list of all the elements for which (PREDICATE element) is nil in SEQUENCE."
+ (seq-filter (lambda (elt) (not (funcall predicate elt)))
+ sequence))
+
+(defun seq-reduce (function sequence initial-value)
+ "Reduce the function FUNCTION across SEQUENCE, starting with INITIAL-VALUE.
+
+Return the result of calling FUNCTION with INITIAL-VALUE and the
+first element of SEQUENCE, then calling FUNCTION with that result and
+the second element of SEQUENCE, then with that result and the third
+element of SEQUENCE, etc.
+
+If SEQUENCE is empty, return INITIAL-VALUE and FUNCTION is not called."
+ (if (seq-empty-p sequence)
+ initial-value
+ (let ((acc initial-value))
+ (seq-doseq (elt sequence)
+ (setq acc (funcall function acc elt)))
+ acc)))
+
+(defun seq-some (predicate sequence)
+ "Return the first value for which if (PREDICATE element) is non-nil for in SEQUENCE."
+ (catch 'seq--break
+ (seq-doseq (elt sequence)
+ (let ((result (funcall predicate elt)))
+ (when result
+ (throw 'seq--break result))))
+ nil))
+
+(defun seq-find (predicate sequence &optional default)
+ "Return the first element for which (PREDICATE element) is non-nil in SEQUENCE.
+If no element is found, return DEFAULT.
+
+Note that `seq-find' has an ambiguity if the found element is
+identical to DEFAULT, as it cannot be known if an element was
+found or not."
+ (catch 'seq--break
+ (seq-doseq (elt sequence)
+ (when (funcall predicate elt)
+ (throw 'seq--break elt)))
+ default))
+
+(defun seq-every-p (predicate sequence)
+ "Return non-nil if (PREDICATE element) is non-nil for all elements of the sequence SEQUENCE."
+ (catch 'seq--break
+ (seq-doseq (elt sequence)
+ (or (funcall predicate elt)
+ (throw 'seq--break nil)))
+ t))
+
+(defun seq-count (predicate sequence)
+ "Return the number of elements for which (PREDICATE element) is non-nil in SEQUENCE."
+ (let ((count 0))
+ (seq-doseq (elt sequence)
+ (when (funcall predicate elt)
+ (setq count (+ 1 count))))
+ count))
+
+(defun seq-empty-p (sequence)
+ "Return non-nil if the sequence SEQUENCE is empty, nil otherwise."
+ (if (listp sequence)
+ (null sequence)
+ (= 0 (seq-length sequence))))
+
+(defun seq-sort (predicate sequence)
+ "Return a sorted sequence comparing using PREDICATE the elements of SEQUENCE.
+The result is a sequence of the same type as SEQUENCE."
+ (if (listp sequence)
+ (sort (seq-copy sequence) predicate)
+ (let ((result (seq-sort predicate (append sequence nil))))
+ (seq-into result (type-of sequence)))))
+
+(defun seq-sort-by (function pred sequence)
+ "Sort SEQUENCE using PRED as a comparison function.
+Elements of SEQUENCE are transformed by FUNCTION before being
+sorted. FUNCTION must be a function of one argument."
+ (seq-sort (lambda (a b)
+ (funcall pred
+ (funcall function a)
+ (funcall function b)))
+ sequence))
+
+(defun seq-contains (sequence elt &optional testfn)
+ "Return the first element in SEQUENCE that equals to ELT.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+ (seq-some (lambda (e)
+ (funcall (or testfn #'equal) elt e))
+ sequence))
+
+(defun seq-set-equal-p (sequence1 sequence2 &optional testfn)
+ "Return non-nil if SEQUENCE1 and SEQUENCE2 contain the same elements, regardless of order.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+ (and (seq-every-p (lambda (item1) (seq-contains sequence2 item1 testfn)) sequence1)
+ (seq-every-p (lambda (item2) (seq-contains sequence1 item2 testfn)) sequence2)))
+
+(defun seq-position (sequence elt &optional testfn)
+ "Return the index of the first element in SEQUENCE that is equal to ELT.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+ (let ((index 0))
+ (catch 'seq--break
+ (seq-doseq (e sequence)
+ (when (funcall (or testfn #'equal) e elt)
+ (throw 'seq--break index))
+ (setq index (1+ index)))
+ nil)))
+
+(defun seq-uniq (sequence &optional testfn)
+ "Return a list of the elements of SEQUENCE with duplicates removed.
+TESTFN is used to compare elements, or `equal' if TESTFN is nil."
+ (let ((result '()))
+ (seq-doseq (elt sequence)
+ (unless (seq-contains result elt testfn)
+ (setq result (cons elt result))))
+ (nreverse result)))
+
+(defun seq-subseq (sequence start &optional end)
+ "Return the subsequence of SEQUENCE from START to END.
+If END is omitted, it defaults to the length of the sequence.
+If START or END is negative, it counts from the end."
+ (cond ((or (stringp sequence) (vectorp sequence)) (substring sequence start end))
+ ((listp sequence)
+ (let (len (errtext (format "Bad bounding indices: %s, %s" start end)))
+ (and end (< end 0) (setq end (+ end (setq len (seq-length sequence)))))
+ (if (< start 0) (setq start (+ start (or len (setq len (seq-length sequence))))))
+ (when (> start 0)
+ (setq sequence (nthcdr (1- start) sequence))
+ (or sequence (error "%s" errtext))
+ (setq sequence (cdr sequence)))
+ (if end
+ (let ((res nil))
+ (while (and (>= (setq end (1- end)) start) sequence)
+ (push (pop sequence) res))
+ (or (= (1+ end) start) (error "%s" errtext))
+ (nreverse res))
+ (seq-copy sequence))))
+ (t (error "Unsupported sequence: %s" sequence))))
+
+(defun seq-concatenate (type &rest seqs)
+ "Concatenate, into a sequence of type TYPE, the sequences SEQS.
+TYPE must be one of following symbols: vector, string or list.
+
+\n(fn TYPE SEQUENCE...)"
+ (pcase type
+ (`vector (apply #'vconcat seqs))
+ (`string (apply #'concat seqs))
+ (`list (apply #'append (append seqs '(nil))))
+ (_ (error "Not a sequence type name: %S" type))))
+
+(defun seq-mapcat (function sequence &optional type)
+ "Concatenate the result of applying FUNCTION to each element of SEQUENCE.
+The result is a sequence of type TYPE, or a list if TYPE is nil."
+ (apply #'seq-concatenate (or type 'list)
+ (seq-map function sequence)))
+
+(defun seq-mapn (function sequence &rest seqs)
+ "Like `seq-map' but FUNCTION is mapped over all SEQS.
+The arity of FUNCTION must match the number of SEQS, and the
+mapping stops on the shortest sequence.
+Return a list of the results.
+
+\(fn FUNCTION SEQS...)"
+ (let ((result nil)
+ (seqs (seq-map (lambda (s)
+ (seq-into s 'list))
+ (cons sequence seqs))))
+ (while (not (memq nil seqs))
+ (push (apply function (seq-map #'car seqs)) result)
+ (setq seqs (seq-map #'cdr seqs)))
+ (nreverse result)))
+
+(defun seq-partition (sequence n)
+ "Return a list of the elements of SEQUENCE grouped into sub-sequences of length N.
+The last sequence may contain less than N elements. If N is a
+negative integer or 0, nil is returned."
+ (unless (< n 1)
+ (let ((result '()))
+ (while (not (seq-empty-p sequence))
+ (push (seq-take sequence n) result)
+ (setq sequence (seq-drop sequence n)))
+ (nreverse result))))
+
+(defun seq-intersection (seq1 seq2 &optional testfn)
+ "Return a list of the elements that appear in both SEQ1 and SEQ2.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+ (seq-reduce (lambda (acc elt)
+ (if (seq-contains seq2 elt testfn)
+ (cons elt acc)
+ acc))
+ (seq-reverse seq1)
+ '()))
+
+(defun seq-difference (seq1 seq2 &optional testfn)
+ "Return a list of the elements that appear in SEQ1 but not in SEQ2.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+ (seq-reduce (lambda (acc elt)
+ (if (not (seq-contains seq2 elt testfn))
+ (cons elt acc)
+ acc))
+ (seq-reverse seq1)
+ '()))
+
+(defun seq-group-by (function sequence)
+ "Apply FUNCTION to each element of SEQUENCE.
+Separate the elements of SEQUENCE into an alist using the results as
+keys. Keys are compared using `equal'."
+ (seq-reduce
+ (lambda (acc elt)
+ (let* ((key (funcall function elt))
+ (cell (assoc key acc)))
+ (if cell
+ (setcdr cell (push elt (cdr cell)))
+ (push (list key elt) acc))
+ acc))
+ (seq-reverse sequence)
+ nil))
+
+(defalias 'seq-reverse
+ (if (ignore-errors (reverse [1 2]))
+ #'reverse
+ (lambda (sequence)
+ "Return the reversed copy of list, vector, or string SEQUENCE.
+See also the function `nreverse', which is used more often."
+ (let ((result '()))
+ (seq-map (lambda (elt) (push elt result))
+ sequence)
+ (if (listp sequence)
+ result
+ (seq-into result (type-of sequence)))))))
+
+(defun seq-into (sequence type)
+ "Convert the sequence SEQUENCE into a sequence of type TYPE.
+TYPE can be one of the following symbols: vector, string or list."
+ (pcase type
+ (`vector (seq--into-vector sequence))
+ (`string (seq--into-string sequence))
+ (`list (seq--into-list sequence))
+ (_ (error "Not a sequence type name: %S" type))))
+
+(defun seq-min (sequence)
+ "Return the smallest element of SEQUENCE.
+SEQUENCE must be a sequence of numbers or markers."
+ (apply #'min (seq-into sequence 'list)))
+
+(defun seq-max (sequence)
+ "Return the largest element of SEQUENCE.
+SEQUENCE must be a sequence of numbers or markers."
+ (apply #'max (seq-into sequence 'list)))
+
+(defun seq-random-elt (sequence)
+ "Return a random element from SEQUENCE.
+Signal an error if SEQUENCE is empty."
+ (if (seq-empty-p sequence)
+ (error "Sequence cannot be empty")
+ (seq-elt sequence (random (seq-length sequence)))))
+
+(defun seq--drop-list (list n)
+ "Return a list from LIST without its first N elements.
+This is an optimization for lists in `seq-drop'."
+ (nthcdr n list))
+
+(defun seq--take-list (list n)
+ "Return a list from LIST made of its first N elements.
+This is an optimization for lists in `seq-take'."
+ (let ((result '()))
+ (while (and list (> n 0))
+ (setq n (1- n))
+ (push (pop list) result))
+ (nreverse result)))
+
+(defun seq--drop-while-list (predicate list)
+ "Return a list from the first element for which (PREDICATE element) is nil in LIST.
+This is an optimization for lists in `seq-drop-while'."
+ (while (and list (funcall predicate (car list)))
+ (setq list (cdr list)))
+ list)
+
+(defun seq--take-while-list (predicate list)
+ "Return the successive elements for which (PREDICATE element) is non-nil in LIST.
+This is an optimization for lists in `seq-take-while'."
+ (let ((result '()))
+ (while (and list (funcall predicate (car list)))
+ (push (pop list) result))
+ (nreverse result)))
+
+(defun seq--count-successive (predicate sequence)
+ "Return the number of successive elements for which (PREDICATE element) is non-nil in SEQUENCE."
+ (let ((n 0)
+ (len (seq-length sequence)))
+ (while (and (< n len)
+ (funcall predicate (seq-elt sequence n)))
+ (setq n (+ 1 n)))
+ n))
+
+;; Helper function for the Backward-compatible version of `seq-let'
+;; for Emacs<25.1.
+(defun seq--make-bindings (args sequence &optional bindings)
+ "Return a list of bindings of the variables in ARGS to the elements of a sequence.
+if BINDINGS is non-nil, append new bindings to it, and return
+BINDINGS."
+ (let ((index 0)
+ (rest-marker nil))
+ (seq-doseq (name args)
+ (unless rest-marker
+ (pcase name
+ ((pred seqp)
+ (setq bindings (seq--make-bindings (seq--elt-safe args index)
+ `(seq--elt-safe ,sequence ,index)
+ bindings)))
+ (`&rest
+ (progn (push `(,(seq--elt-safe args (1+ index))
+ (seq-drop ,sequence ,index))
+ bindings)
+ (setq rest-marker t)))
+ (_
+ (push `(,name (seq--elt-safe ,sequence ,index)) bindings))))
+ (setq index (1+ index)))
+ bindings))
+
+(defun seq--elt-safe (sequence n)
+ "Return element of SEQUENCE at the index N.
+If no element is found, return nil."
+ (when (or (listp sequence)
+ (and (sequencep sequence)
+ (> (seq-length sequence) n)))
+ (seq-elt sequence n)))
+
+(defun seq--activate-font-lock-keywords ()
+ "Activate font-lock keywords for some symbols defined in seq."
+ (font-lock-add-keywords 'emacs-lisp-mode
+ '("\\<seq-doseq\\>" "\\<seq-let\\>")))
+
+(defalias 'seq-copy #'copy-sequence)
+(defalias 'seq-elt #'elt)
+(defalias 'seq-length #'length)
+(defalias 'seq-do #'mapc)
+(defalias 'seq-each #'seq-do)
+(defalias 'seq-map #'mapcar)
+(defalias 'seqp #'sequencep)
+
+(defun seq--into-list (sequence)
+ "Concatenate the elements of SEQUENCE into a list."
+ (if (listp sequence)
+ sequence
+ (append sequence nil)))
+
+(defun seq--into-vector (sequence)
+ "Concatenate the elements of SEQUENCE into a vector."
+ (if (vectorp sequence)
+ sequence
+ (vconcat sequence)))
+
+(defun seq--into-string (sequence)
+ "Concatenate the elements of SEQUENCE into a string."
+ (if (stringp sequence)
+ sequence
+ (concat sequence)))
+
+(unless (fboundp 'elisp--font-lock-flush-elisp-buffers)
+ ;; In Emacsā„25, (via elisp--font-lock-flush-elisp-buffers and a few others)
+ ;; we automatically highlight macros.
+ (add-hook 'emacs-lisp-mode-hook #'seq--activate-font-lock-keywords))
+
+(provide 'seq-24)
+;;; seq-24.el ends here
projects / emacs-init.git / blobdiff