Skylighting.Regex

A representation of a regular expression.

The compiled regex and its capturing groups (cached in the RE by the smart constructor).

Compile a UTF-8 encoded ByteString as a Regex. If the first parameter is True, then the Regex will be case sensitive. If the second parameter is True, quantifiers are minimal (lazy) rather than greedy by default, and the ? modifier makes them greedy instead of lazy -- this corresponds to PCRE's UNGREEDY option (QRegularExpression's InvertedGreedinessOption, set by minimal="1" in KDE syntax definitions).

Match a Regex against a (presumed UTF-8 encoded) ByteString, returning the matched text and a map of (offset, size) pairs for captures. Note that all matches are from the beginning of the string (a ^ anchor is implicit). As in PCRE, the match returned is the first one that a backtracking matcher would find (leftmost alternatives are preferred), which is not necessarily the longest. Note also that to avoid pathological performance in certain cases, the matcher is limited to considering 2000 possible matches at a time; when that threshold is reached, it discards lower-priority matches. Hence certain regexes may incorrectly fail to match: e.g. a*a{3000}$ on a string of 3000 as.

Like matchRegex, but takes the map of capturing groups (as computed by extractCapturingGroups) as an argument, so that it can be computed once per regex instead of once per match. (The map is only consulted for regexes containing subroutine calls like (?1) or (?R).)