[antlr-interest] yet more thoughts on error handling / recovery

[Monty Zukowski]

>
> Rather than print the grammar out as a string for use by the error 
> reporting, perhaps the entire tree structure (i.e., the processed 
> grammar) should be made available to the running parser. The grammar 
> position would map to an actual AST node. The cost would be a slightly 
> larger string (flattened AST as string) compared to the original 
> grammar, but would potentially provide more grammar information to a 
> reporting facility. Hmm...actually, since the trees have down/right 
> pointers (not up/left) it would be hard to walk backwards to print out 
> a larger portion of the grammar. Ok, forget that.

It's not _that_ big a deal to implement up/left pointers.  See my GCC 
grammar :)  Just jump up to the enclosing alt and you're set.

Monty

ANTLR & Java Consultant -- http://www.codetransform.com
ANSI C/GCC transformation toolkit -- 
http://www.codetransform.com/gcc.html
Embrace the Decay -- http://www.codetransform.com/EmbraceDecay.html



 
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