Re: Emulating advanced regex features using Lua patterns and pure Lua code

[David Kastrup <dak@...>]

steve donovan <steve.j.donovan@gmail.com> writes:

> On Mon, Jun 20, 2011 at 12:12 PM, Lorenzo Donati
> <lorenzodonatibz@interfree.it> wrote:
>> if pcre.match( haystack, "^foo|bar$" ) then ...
>> may be rewritten in pure Lua as:
>> if haystack:match "^foo$" or haystack:match "^bar$" then ...
>
> Ah, but soon as you get multiple alternation, especially nested, then
> the resulting code is not so obvious. And obviously it is going to be
> slower than any regexp implementation. OK, that may be acceptable for
> the application, but the code generation could get hairy fast.
>
> Another idea is to use LPeg to implement a regexp subset - that should
> be fast. But it does require non-triivial knowledge of LPeg which I
> understand is not on your immediate to-do list ;)

<URL:http://www.inf.puc-rio.br/~roberto/lpeg/re.html>

-- 
David Kastrup