need a way to match at beginning of string when start > 0

[timotheecour]

following https://github.com/nitely/nim-regex/pull/67, ^ now refers to position 0 (instead of start) even if start > 0. We need a way to allow matching at position = start (ie emulate the behavior of ^ before https://github.com/nitely/nim-regex/pull/67).

As suggested here https://github.com/nitely/nim-regex/issues/64#issuecomment-622289959, how about adding a bool flag, treatStartAsStart, with perhaps a better name?

note

• IIRC, match behaves differently from find for ^ when start > 0
• refs https://github.com/nim-lang/Nim/issues/14284#issuecomment-719762424
• D20201030T143134

[nitely]

What about passing a slice? or an openArray?

IIRC, match behaves differently from find for ^ when start > 0

Yeah, it does. Maybe it needs fixing.

[timotheecour]

What about passing a slice? or an openArray?

that would prevent using context eg lookaround: (?=T|^S)suffi note that this currently gives Invalid lookaround, expected closing symbol. Beware lookaround is currently limited to match one single character but that's a limitation that (hopefully) will be lifted in the future (as in D's regex + other libs), so openArray would not help there.

Note that supporting openArray is independently useful.

[nitely]

Oh, a special case. I'll wait for re/nre to implement it anyway.

btw, is there a regex engine that has this feature? I tried Python's re, but it works just like re/nre.

[timotheecour]

I'm not sure; but supporting openArray would indeed help in the meantime

[auxym]

I think this would be a useful feature (allowing ^ to match at position start instead of fixed 0), whether as default behavior or with a flag.

Edit: Or alternatively, find/match procs that accept openArray[char] for the input string.