diff options
Diffstat (limited to 'lisp/emacs-lisp/rx.el')
| -rw-r--r-- | lisp/emacs-lisp/rx.el | 32 |
1 files changed, 18 insertions, 14 deletions
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el index 85e74f28ef0..bb759011513 100644 --- a/lisp/emacs-lisp/rx.el +++ b/lisp/emacs-lisp/rx.el @@ -1183,24 +1183,28 @@ enclosed in `(and ...)'. (pcase-defmacro rx (&rest regexps) - "Build a `pcase' pattern matching `rx' regexps. -The REGEXPS are interpreted as by `rx'. The pattern matches if -the regular expression so constructed matches EXPVAL, as if -by `string-match'. + "Build a `pcase' pattern matching `rx' REGEXPS in sexp form. +The REGEXPS are interpreted as in `rx'. The pattern matches any +string that is a match for the regular expression so constructed, +as if by `string-match'. In addition to the usual `rx' constructs, REGEXPS can contain the following constructs: - (let VAR FORM...) creates a new explicitly numbered submatch - that matches FORM and binds the match to - VAR. - (backref VAR) creates a backreference to the submatch - introduced by a previous (let VAR ...) - construct. - -The VARs are associated with explicitly numbered submatches -starting from 1. Multiple occurrences of the same VAR refer to -the same submatch. + (let REF SEXP...) creates a new explicitly named reference to + a submatch that matches regular expressions + SEXP, and binds the match to REF. + (backref REF) creates a backreference to the submatch + introduced by a previous (let REF ...) + construct. REF can be the same symbol + in the first argument of the corresponding + (let REF ...) construct, or it can be a + submatch number. It matches the referenced + submatch. + +The REFs are associated with explicitly named submatches starting +from 1. Multiple occurrences of the same REF refer to the same +submatch. If a case matches, the match data is modified as usual so you can use it in the case body, but you still have to pass the correct |