[antlr-interest] how to allow keywords as variables

[Terence Parr]

On Thursday, June 5, 2003, at 11:22  PM, Ruslan Zasukhin wrote:

> on 6/6/03 1:57, mzukowski at yci.com at mzukowski at yci.com wrote:
>
>> 2.7.2 still does not hoist, with the exception of hoisting from lexer 
>> rules
>> into the nextToken() method.
>>
>> Ter's method would look like
>>
>> id_or_keyword:
>> ID
>> |"if"
>> |"else"
>> ;
>>
>> But this still can be cumbersome and generate lots of ambiguities 
>> which you
>> might need to straighten out with syntactic predicates.
>
> Okay, I see.
>
> It seems I also have hear in mp3 word about ability resolve this using 
> stack
> of context state.

Yes, something like what you have below.  You can do the "state" here 
or in a separate TokenStream object that manipulates the token stream, 
changing "table" to ID when necessary.

Terence
>
> What about this?
>
> For example
>
>     "drop" "table" { ExpectIdNow = true; }  ID
>
> And in lexer
>
>     ID:
>         if( ExpectIdNow )
>             then allow ID or keyword
>         else
>             keywords only.
>
> Or something such?
>
> -- 
> Best regards,
> Ruslan Zasukhin      [ I feel the need...the need for speed ]
> -------------------------------------------------------------
> e-mail: ruslan at paradigmasoft.com
> web: http://www.paradigmasoft.com
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