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Re: Exposing regexp engine & compiled regexp's

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From:
Damian Conway
Date:
January 8, 2001 14:53
Subject:
Re: Exposing regexp engine & compiled regexp's
Message ID:
200101082253.JAA27075@indy05.csse.monash.edu.au
   
   > I once brutalized Henry Spencer's engine into telling me when I was
   > on my way to a match.  This was for a UI: I wanted to be able to say
   > that the input should only match this RE, and if they typed something
   > that broke the match, I could beep and disallow the character.
   > 
   > I was just a greenhorn then, so it coredumped.  But it's another use
   > for access to internal engine states and failure reasons.

Good point. Perhaps, on failure, a regex could set $@ to indicate what the
problem was:

	while (gui_getchar($nextchar)) {
		$input.$nextchar =~ m/$pattern/;
		if ($@ =~ /fail/) { beep }
		else              { $input .= $nextchar }
	}

Damian

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