Re: lpeg.match
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- Subject: Re: lpeg.match
- From: roberto@... (Roberto Ierusalimschy)
- Date: Thu, 1 Mar 2007 09:21:06 -0300
> Please correct me if I am wrong, but my inspection of lpeg.c
> (the documentation is not very specific) persuades me that if
> pattern:match(text) fails then it returns nil.
Right.
> Would it not be more useful if an error object could be returned
> as well? In writing a grammar one wants to be able to create
> context-bearing error messages sometimes:
>
> grammar = lpeg.P { ...
> [NonTerminal] = Pattern_if_OK + Fail(grammar.name,Name[NonTerminal]);
> .... }
Do you think we need explicit support for this? Can't the application do
it by itself? For instance, in your example, "Fail" could build a
pattern that always matches and captures an error object.
-- Roberto