Re: The NOT construct

On 21-01-2025 09:14, Liam R. E. Quin wrote:
> Some musings from regular expression land...
>
> For the keyword case one could conceivably have a construct that must
> match a boundary. Some regular expression languages have \b or \< and
> \> to match a boundary between word and non-word (\b is symmetrical, \<
> matches start and \> end of word). The construct does not consume any
> input, does not match a character, you can't write \<* in such a
> language, but you could then say
>
> functionCall: !(keyword \>), S*, QName ...
I would love to have \b (and \<, \>) in ixml!
(Unfortunately, the PEG parser generator that I work with (in one of my 
projects) does not support \b, but that has nothing to do with ixml.)

Lookahead assertions in regular expressions (and PEG) are very powerful, 
but I think they might not be easy to implement in the kind of parser 
generators that are used for ixml. I hope that someone will prove me 
wrong about that.

Received on Tuesday, 21 January 2025 08:24:07 UTC