string.regexp.match

Returns whether the pattern matches the whole of str.

Parameters

Return value

true when the pattern matches all of str, from the first character to the last. false for an ordinary mismatch. false never means the match was aborted, see Errors.

Errors

Throws regexp match aborted: pattern too complex for this input instead of returning false when matching exceeds the engine's backtracking budget - for example a pattern with nested unbounded quantifiers tried against a long non-matching input. It is a runtime safety limit, not a syntax error, so it can happen on any pattern given a bad enough input.

Notes

match is anchored at both ends. Use search to test whether the pattern occurs anywhere inside str, and capture to get its capturing groups too.

Example

from "string" import regexp

let digits = regexp("[0-9]+")
println("digits.match(\"12345\") =", digits.match("12345"))       // the whole string has to match
println("digits.match(\"12345 items\") =", digits.match("12345 items")) // trailing text fails the match

// a pattern that forces runaway backtracking throws rather than hanging
local s = ""
for (local i = 0; i < 26; i++) s += "a"
try {
  regexp("(a+)+b").match(s)
} catch (e) {
  println("regexp(\"(a+)+b\").match(s) throws:", e)
}

digits.match("12345") = true
digits.match("12345 items") = false
regexp("(a+)+b").match(s) throws: regexp match aborted: pattern too complex for this input

See also