Re: [Flex-devel] [PATCH] Continued Actions and <<EOF>>

[Will E. <wl...@us...>]

Thanks for your report.

Looks like a good catch. I've got  to get a release out to address some
serious problems with 2.5.34, so I'm going to fully investigate this
after that work is done. ("Fully investigate" will include adding a test
to catch this particular bug.)

On Sunday, 17 February 2008,  5:35 am -0500, Michael Witten <mfw...@MI...> wrote:

>  Hello,
> 
>  Consider the following, in which the special continued action
>  symbol '|' refers to the action of an <<EOF>>:
> 
>  	pattern |
>  	<<EOF>> { /* some action */ }
> 
>  Unfortunately, this produces a buggy scanner, because an <<EOF>>
>  action's case block doesn't begin with a "YY_RULE_SETUP", so that
>  any regular rule that drops into that case block will not be properly
>  initialized.
> 
>  I have provided a patch that simply modifies build_eof_action() in parse.y
>  to check whether a YY_RULE_SETUP should be emitted for the previous rule
>  (before the <<EOF>> case statement).
> 
>  The patch can be accessed in 2 ways:
> 
>  	(1) The attachment
>  	(3) 
>  https://sourceforge.net/tracker/download.php?group_id=97492&atid=618179&file_id=266698&aid=1895336
> 
>  There is also an inlined version below, but the mailer renders it useless
>  unless you fill in the removed whitespace-only lines by hand.
> 
>  Please give your comments.
> 
>  Sincerely,
>  Michael Witten
> 
>  Index: parse.y
>  ===================================================================
>  RCS file: /cvsroot/flex/flex/parse.y,v
>  retrieving revision 2.50
>  diff -u -8 -p -r2.50 parse.y
>  --- parse.y	15 Feb 2008 12:37:35 -0000	2.50
>  +++ parse.y	17 Feb 2008 10:06:16 -0000
>  @@ -963,16 +963,20 @@ void build_eof_action()
>   		if ( sceof[scon_stk[i]] )
>   			format_pinpoint_message(
>   				"multiple <<EOF>> rules for start condition %s",
>   				scname[scon_stk[i]] );
> 
>   		else
>   			{
>   			sceof[scon_stk[i]] = true;
>  +
>  +			if (previous_continued_action /* && previous action was regular */)
>  +				add_action("YY_RULE_SETUP\n");
>  +
>   			snprintf( action_text, sizeof(action_text), "case YY_STATE_EOF(%s):\n",
>   				scname[scon_stk[i]] );
>   			add_action( action_text );
>   			}
>   		}
> 
>   	line_directive_out( (FILE *) 0, 1 );
> 
> 


> 

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-- 
Will Estes
Flex Project Maintainer
http://flex.sourceforge.net/