[Emacs-diffs] trunk r113457: split-string takes a new arg TRIM that's a regexp

[Richard M. Stallman]

------------------------------------------------------------
revno: 113457
revision-id: address@hidden
parent: address@hidden
committer: Richard Stallman <address@hidden>
branch nick: trunk
timestamp: Fri 2013-07-19 08:18:16 -0400
message:
  split-string takes a new arg TRIM that's a regexp
  saying what to trim from the start and end of each substring.
  
  * subr.el (split-string): New arg TRIM.
modified:
  etc/NEWS                       news-20100311060928-aoit31wvzf25yr1z-1
  lisp/ChangeLog                 changelog-20091113204419-o5vbwnq5f7feedwu-1432
  lisp/subr.el                   subr.el-20091113204419-o5vbwnq5f7feedwu-151

=== modified file 'etc/NEWS'
--- a/etc/NEWS  2013-07-16 11:41:06 +0000
+++ b/etc/NEWS  2013-07-19 12:18:16 +0000
@@ -561,6 +561,9 @@
 *** `completion-in-region-function' obsoletes `completion-in-region-functions'.
 *** `filter-buffer-substring-function' obsoletes 
`filter-buffer-substring-functions'.
 
+** `split-string' now takes an optional argument TRIM.
+The value, if non-nil, is a regexp that specifies what to trim from
+the start and end of each substring.
 
 ** `get-upcase-table' is obsoleted by the new `case-table-get-table'.
 

=== modified file 'lisp/ChangeLog'
--- a/lisp/ChangeLog    2013-07-19 00:38:19 +0000
+++ b/lisp/ChangeLog    2013-07-19 12:18:16 +0000
@@ -1,3 +1,7 @@
+2013-07-19  Richard Stallman  <address@hidden>
+
+       * subr.el (split-string): New arg TRIM.
+
 2013-07-18  Juanma Barranquero  <address@hidden>
 
        * frame.el (blink-cursor-timer-function, blink-cursor-suspend):

=== modified file 'lisp/subr.el'
--- a/lisp/subr.el      2013-07-11 01:49:17 +0000
+++ b/lisp/subr.el      2013-07-19 12:18:16 +0000
@@ -3529,7 +3529,7 @@
 ;; defaulted, OMIT-NULLS should be treated as t.  Simplifying the logical
 ;; expression leads to the equivalent implementation that if SEPARATORS
 ;; is defaulted, OMIT-NULLS is treated as t.
-(defun split-string (string &optional separators omit-nulls)
+(defun split-string (string &optional separators omit-nulls trim)
   "Split STRING into substrings bounded by matches for SEPARATORS.
 
 The beginning and end of STRING, and each match for SEPARATORS, are
@@ -3547,17 +3547,50 @@
 are effectively trimmed).  If nil, all zero-length substrings are retained,
 which correctly parses CSV format, for example.
 
+If TRIM is non-nil, it should be a regular expression to match
+text to trim from the beginning and end of each substring.  If trimming
+makes the substring empty, it is treated as null.
+
+If you want to trim whitespace from the substrings, the reliably correct
+way is using TRIM.  Making SEPARATORS match that whitespace gives incorrect
+results when there is whitespace at the start or end of STRING.  If you
+see such calls to `split-string', please fix them.
+
 Note that the effect of `(split-string STRING)' is the same as
 `(split-string STRING split-string-default-separators t)'.  In the rare
 case that you wish to retain zero-length substrings when splitting on
 whitespace, use `(split-string STRING split-string-default-separators)'.
 
 Modifies the match data; use `save-match-data' if necessary."
-  (let ((keep-nulls (not (if separators omit-nulls t)))
-       (rexp (or separators split-string-default-separators))
-       (start 0)
-       notfirst
-       (list nil))
+  (let* ((keep-nulls (not (if separators omit-nulls t)))
+        (rexp (or separators split-string-default-separators))
+        (start 0)
+        this-start this-end
+        notfirst
+        (list nil)
+        (push-one
+         ;; Push the substring in range THIS-START to THIS-END
+         ;; onto LIST, trimming it and perhaps discarding it.
+         (lambda ()
+           (when trim
+             ;; Discard the trim from start of this substring.
+             (let ((tem (string-match trim string this-start)))
+               (and (eq tem this-start)
+                    (setq this-start (match-end 0)))))
+
+           (when (or keep-nulls (< this-start this-end))
+             (let ((this (substring string this-start this-end)))
+
+               ;; Discard the trim from end of this substring.
+               (when trim
+                 (let ((tem (string-match (concat trim "\\'") this 0)))
+                   (and tem (< tem (length this))
+                        (setq this (substring this 0 tem)))))
+
+               ;; Trimming could make it empty; check again.
+               (when (or keep-nulls (> (length this) 0))
+                 (push this list)))))))
+
     (while (and (string-match rexp string
                              (if (and notfirst
                                       (= start (match-beginning 0))
@@ -3565,15 +3598,15 @@
                                  (1+ start) start))
                (< start (length string)))
       (setq notfirst t)
-      (if (or keep-nulls (< start (match-beginning 0)))
-         (setq list
-               (cons (substring string start (match-beginning 0))
-                     list)))
-      (setq start (match-end 0)))
-    (if (or keep-nulls (< start (length string)))
-       (setq list
-             (cons (substring string start)
-                   list)))
+      (setq this-start start this-end (match-beginning 0)
+           start (match-end 0))
+
+      (funcall push-one))
+
+    ;; Handle the substring at the end of STRING.
+    (setq this-start start this-end (length string))
+    (funcall push-one)
+
     (nreverse list)))
 
 (defun combine-and-quote-strings (strings &optional separator)