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(split-string): Implement specification that splitting on explicit separators

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retains null fields.  Add new argument OMIT-NULLS.  Special-case (split-string
"a string").
This commit is contained in:
Juanma Barranquero 2003-05-22 20:59:57 +00:00
parent 7933722aa4
commit 6a64662696
1 changed files with 42 additions and 18 deletions
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60
lisp/subr.el
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@ -1820,19 +1820,45 @@ STRING should be given if the last search was by `string-match' on STRING."
(buffer-substring-no-properties (match-beginning num)
(match-end num)))))
(defun split-string (string &optional separators)
"Splits STRING into substrings where there are matches for SEPARATORS.
Each match for SEPARATORS is a splitting point.
The substrings between the splitting points are made into a list
which is returned.
If SEPARATORS is absent, it defaults to \"[ \\f\\t\\n\\r\\v]+\".
(defconst split-string-default-separators "[ \f\t\n\r\v]+"
"The default value of separators for `split-string'.
If there is match for SEPARATORS at the beginning of STRING, we do not
include a null substring for that. Likewise, if there is a match
at the end of STRING, we don't include a null substring for that.
A regexp matching strings of whitespace. May be locale-dependent
\(as yet unimplemented). Should not match non-breaking spaces.
Warning: binding this to a different value and using it as default is
likely to have undesired semantics.")
;; The specification says that if both SEPARATORS and OMIT-NULLS are
;; 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)
"Splits STRING into substrings bounded by matches for SEPARATORS.
The beginning and end of STRING, and each match for SEPARATORS, are
splitting points. The substrings matching SEPARATORS are removed, and
the substrings between the splitting points are collected as a list,
which is returned.
If SEPARATORS is non-nil, it should be a regular expression matching text
which separates, but is not part of, the substrings. If nil it defaults to
`split-string-default-separators', normally \"[ \\f\\t\\n\\r\\v]+\", and
OMIT-NULLS is forced to t.
If OMIT-NULLs is t, zero-length substrings are omitted from the list \(so
that for the default value of SEPARATORS leading and trailing whitespace
are effectively trimmed). If nil, all zero-length substrings are retained,
which correctly parses CSV format, for example.
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 ((rexp (or separators "[ \f\t\n\r\v]+"))
(let ((keep-nulls (not (if separators omit-nulls t)))
(rexp (or separators split-string-default-separators))
(start 0)
notfirst
(list nil))
@ -1841,16 +1867,14 @@ Modifies the match data; use `save-match-data' if necessary."
(= start (match-beginning 0))
(< start (length string)))
(1+ start) start))
(< (match-beginning 0) (length string)))
(< start (length string)))
(setq notfirst t)
(or (eq (match-beginning 0) 0)
(and (eq (match-beginning 0) (match-end 0))
(eq (match-beginning 0) start))
(if (or keep-nulls (< start (match-beginning 0)))
(setq list
(cons (substring string start (match-beginning 0))
list)))
(setq start (match-end 0)))
(or (eq start (length string))
(if (or keep-nulls (< start (length string)))
(setq list
(cons (substring string start)
list)))
@ -1868,7 +1892,7 @@ Unless optional argument INPLACE is non-nil, return a new string."
newstr))
(defun replace-regexp-in-string (regexp rep string &optional
fixedcase literal subexp start)
fixedcase literal subexp start)
"Replace all matches for REGEXP with REP in STRING.
Return a new string containing the replacements.
@ -1917,7 +1941,7 @@ and replace a sub-expression, e.g.
rep
(funcall rep (match-string 0 str)))
fixedcase literal str subexp)
(cons (substring string start mb) ; unmatched prefix
(cons (substring string start mb) ; unmatched prefix
matches)))
(setq start me))
;; Reconstruct a string from the pieces.
@ -2157,7 +2181,7 @@ included in the mode-line minor mode menu.
If TOGGLE has a `:menu-tag', that is used for the menu item's label."
(unless (memq toggle minor-mode-list)
(push toggle minor-mode-list))
(unless toggle-fun (setq toggle-fun toggle))
;; Add the name to the minor-mode-alist.
(when name