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| author | Mattias Engdegård <mattiase@acm.org> | 2019-05-15 22:44:00 +0200 |
|---|---|---|
| committer | Mattias Engdegård <mattiase@acm.org> | 2019-05-20 17:56:40 +0200 |
| commit | afdc20d73c8588e5a744ecf7bffaf4401a557d20 (patch) | |
| tree | fa09854d24edb81160a2d709bd450ea7284d83f1 /lisp/emacs-lisp | |
| parent | c2cda3ff4025e8c27bdfc2a5279f3b635c8df260 (diff) | |
| download | emacs-afdc20d73c8588e5a744ecf7bffaf4401a557d20.tar.gz emacs-afdc20d73c8588e5a744ecf7bffaf4401a557d20.tar.bz2 emacs-afdc20d73c8588e5a744ecf7bffaf4401a557d20.zip | |
Allow zero-argument rx `or' and `seq' forms
Make the rx `or' and `seq' forms accept zero arguments to produce a
never-matching regexp and an empty string, respectively.
* lisp/emacs-lisp/rx.el: Require cl-extra.
(rx-constituents, rx-or): Permit zero args.
(rx): Amend doc string for `or' and `seq'.
* test/lisp/emacs-lisp/rx-tests.el (rx-or, rx-seq): Test the change.
* etc/NEWS (Changes in Specialized Modes and Packages): Mention the change.
Diffstat (limited to 'lisp/emacs-lisp')
| -rw-r--r-- | lisp/emacs-lisp/rx.el | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el index 9d9028d87d5..ed32490ceee 100644 --- a/lisp/emacs-lisp/rx.el +++ b/lisp/emacs-lisp/rx.el @@ -106,15 +106,16 @@ ;;; Code: (require 'cl-lib) +(require 'cl-extra) ;; FIXME: support macros. (defvar rx-constituents ;Not `const' because some modes extend it. - '((and . (rx-and 1 nil)) + '((and . (rx-and 0 nil)) (seq . and) ; SRE (: . and) ; SRE (sequence . and) ; sregex - (or . (rx-or 1 nil)) + (or . (rx-or 0 nil)) (| . or) ; SRE (not-newline . ".") (nonl . not-newline) ; SRE @@ -390,9 +391,11 @@ FORM is of the form `(and FORM1 ...)'." "Parse and produce code from FORM, which is `(or FORM1 ...)'." (rx-check form) (rx-group-if - (if (memq nil (mapcar 'stringp (cdr form))) - (mapconcat (lambda (x) (rx-form x '|)) (cdr form) "\\|") + (cond + ((null (cdr form)) regexp-unmatchable) + ((cl-every #'stringp (cdr form)) (regexp-opt (cdr form) nil t)) + (t (mapconcat (lambda (x) (rx-form x '|)) (cdr form) "\\|"))) (and (memq rx-parent '(: * t)) rx-parent))) @@ -1121,6 +1124,7 @@ CHAR `(seq SEXP1 SEXP2 ...)' `(sequence SEXP1 SEXP2 ...)' matches what SEXP1 matches, followed by what SEXP2 matches, etc. + Without arguments, matches the empty string. `(submatch SEXP1 SEXP2 ...)' `(group SEXP1 SEXP2 ...)' @@ -1136,7 +1140,7 @@ CHAR `(| SEXP1 SEXP2 ...)' matches anything that matches SEXP1 or SEXP2, etc. If all args are strings, use `regexp-opt' to optimize the resulting - regular expression. + regular expression. Without arguments, never matches anything. `(minimal-match SEXP)' produce a non-greedy regexp for SEXP. Normally, regexps matching |