[antlr-interest] Grammar seems to produce incorrect parser

[Ric Klaren]

On Thu, Jan 22, 2004 at 12:58:58AM -0000, stanhuff wrote:
> grammar throws exceptions if "is null" is not found. How can I change 
> my grammar to get the desired parser?
> 
> class ExpressionParser extends Parser;
> options {defaultErrorHandler=false;}
> expression 
> 	:	simpleExpression ("is" "null")?
> 	;

For starters try:

expression 
:	simpleExpression ("is" "null")? EOF 
;

This of course will only work for input with a single expression followed
by end of file. If you want it to stop parsing after one expression leaving
the rest of the stream untouched then it won't work :/

Intuitively I wouldn't expect the throw in the generated code.... But my
intuition might be wrong ;)

Cheers,

Ric
--
-----+++++*****************************************************+++++++++-------
    ---- Ric Klaren ----- j.klaren at utwente.nl ----- +31 53 4893722  ----
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