first-match ( string regexp -- slice/f )
Regular expressions » Matching operations with regular expressions

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Vocabulary
regexp

Inputs

string	a string
regexp	a regexp

Outputs

slice/f

the match, if one exists

Word description
Finds the first match of the regular expression in the string, and returns it as a slice. If there is no match, then f is returned.

Definition

USING: kernel math regexp.private sequences.private ;

IN: regexp

:: first-match ( string regexp -- slice/f )
    string regexp prepare-match-iterator do-next-match [
        regexp reverse-regexp? [ [ 1 + ] bi@ ] when
        string <slice-unsafe>
    ] [ 2drop f ] if ;