Re: [Boost-users] [regex] ECMAScript conformance

From: John Maddock (john_at_[hidden])
Date: 2007-05-30 04:37:30

Armel Asselin wrote:
> though, there are a few inconsistencies though with the ECMAScript
> spec.
> 1. it seems that re-matching an atom does not first clear its
> sub-matches, as "step 4" in page 135 of ECMA 262 3rd edition tells to.
>
> that is, it does what is in the 'and not' part here:
>
> /(z)((a+)?(b+)?(c))*/.exec("zaacbbbcac")
> which returns the array
> ["zaacbbbcac", "z", "ac", "a", undefined, "c"]
> and not
> ["zaacbbbcac", "z", "ac", "a", "bbb", "c"]

I'll look into it.

> 2. the {n,m} notation should not accept spaces in ECMAScript mode
> (though it's practical, it's not conformant). I easily admit that its
> not really important.

I regard that as a compatible extension :-)  I do remember that allowing 
spaces was a deliberate policy, but whether for compatibility with Perl or 
POSIX I don't recall.

Thanks for the feedback, John.