[antlr-interest] forcing parenthesis (no precedence)

[hakan eryargi]

thank you all. this effectively solved my problem :)

On Thu, Jul 16, 2009 at 5:55 PM, David-Sarah
Hopwood<david-sarah at jacaranda.org> wrote:
> Stuart Dootson wrote:
>> On Thu, Jul 16, 2009 at 1:21 PM, hakan eryargi <hakan.eryargi at gmail.com> wrote:
>>> i will really appreciate a simple sample if possible :)
>>
>> Simple grammar that mimics the Ada approach:
>>
>> grammar test;
>>
>> program  :   expression EOF
>>          ;
>>
>> expression
>>          :  primary ( ('AND' primary ) + | ( 'OR' primary ) +)
>>          ;
>
> This doesn't allow a single <primary> that does not use AND/OR as an
> <expression>. You want something like:
>
>  expression
>           :  primary ( ('AND' primary ) + | ( 'OR' primary ) +)?
>           ;
>
> (It's also preferable to declare all of the tokens, as in my other reply.)
>
>> primary  :  VARIABLE
>>          |  'TRUE'
>>          |  'FALSE'
>>          |  '(' expression ')'
>>          ;
>>
>> VARIABLE :  'a'..'z' +
>>          ;
>
> --
> David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com
>
>
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