Warning: This is the manual of the legacy Guile 2.0 series. You may want to read the manual of the current stable series instead.
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A match structure is the object returned by string-match
and
regexp-exec
. It describes which portion of a string, if any,
matched the given regular expression. Match structures include: a
reference to the string that was checked for matches; the starting and
ending positions of the regexp match; and, if the regexp included any
parenthesized subexpressions, the starting and ending positions of each
submatch.
In each of the regexp match functions described below, the match
argument must be a match structure returned by a previous call to
string-match
or regexp-exec
. Most of these functions
return some information about the original target string that was
matched against a regular expression; we will call that string
target for easy reference.
Return #t
if obj is a match structure returned by a
previous call to regexp-exec
, or #f
otherwise.
Return the portion of target matched by subexpression number
n. Submatch 0 (the default) represents the entire regexp match.
If the regular expression as a whole matched, but the subexpression
number n did not match, return #f
.
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:substring s) ⇒ "2002" ;; match starting at offset 6 in the string (match:substring (string-match "[0-9][0-9][0-9][0-9]" "blah987654" 6)) ⇒ "7654"
Return the starting position of submatch number n.
In the following example, the result is 4, since the match starts at character index 4:
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:start s) ⇒ 4
Return the ending position of submatch number n.
In the following example, the result is 8, since the match runs between characters 4 and 8 (i.e. the “2002”).
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:end s) ⇒ 8
Return the unmatched portion of target preceding the regexp match.
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:prefix s) ⇒ "blah"
Return the unmatched portion of target following the regexp match.
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:suffix s) ⇒ "foo"
Return the number of parenthesized subexpressions from match. Note that the entire regular expression match itself counts as a subexpression, and failed submatches are included in the count.
Return the original target string.
(define s (string-match "[0-9][0-9][0-9][0-9]" "blah2002foo")) (match:string s) ⇒ "blah2002foo"
Next: Backslash Escapes, Previous: Regexp Functions, Up: Regular Expressions [Contents][Index]