Re: re-entrant parsers, pure_parser, bison, flex

PJ Mealy writes:
> As the GUI is structured around an event processing loop
> I can't just go ahead and do the full parse in one go.
> I need to have the event loop active periodically to process
> progress bar updates and respond to a click on the CANCEL button.


Sure you can. Just invert the approach. Think INPUT.
Add whatever you need into the yylex() function.
It is already a state driven machine that maintains its own data.
You could call your event loop each time yylex() is called,
or maintain a counter and call your event loop every 100-1000
times, or check your time and call it every second.
Define a variable global to yylex() and your cancel processing,
clear it in your main routine, set it in your cancel routine,
and test it in yylex(): if set, tell parser abnormal end of
input requested by user.


--
Take care.
Thanks,
Brian Inglis
Brian_Inglis@CompuServe.COM
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