[antlr-interest] simple arithmetic counter

[Tobias Wunner]

Thanks a lot for all this Info!

Everything worked.

Regards,
Toby

On Apr 9, 2009, at 6:23 AM, Indhu Bharathi wrote:

> Use '@members' to store 'global' variables.
>
> like
> @members{
>     int cnt;
> }
>
> and increase 'cnt' in 'species' production, like
>
> species
>     : ret=atom NUMBER?
>     {
>         cnt += $ret.weight * Integer.parseInt($NUMBER.text)
>     }
>         ;
>
> and print out the sum in file production, like
>
> file
>     : species*
>     {
>         System.out.println(cnt);
>     }
>     ;
>
> In ANTLRWorks, you'll see the printed out value in output tab.
>
> - Indhu
>
> Tobias Wunner wrote:
>>
>> Hello,
>>
>> I am a absolute beginner to ANTLR. I already worked through some  
>> tutorials but couldn't solve my problem. I would like to add some  
>> numbers encoded by strings and print them to STDOUT or display them  
>> in the ANTLR Debug environment (to test if my calculations were  
>> correct). Two things I didn't find out:
>>
>> how to display or print out used variables
>> how to use a global variable as a counter and inrease it e.g. cnt+=a
>>
>> To start I found a simple grammar for chemical terms beeing able to  
>> calculate the weight of things like "H2O" or "Cl2".
>>
>> file : species*;
>> species : atom DIGITS? {};
>> atom returns [double weight]
>>  : 'H' { $weight = 1.00794; }
>>  | 'C' { $weight = 12.001; }
>>  | 'Cl' { $weight = 35.453; }
>>  | 'O' { $weight = 15.999; }
>>  | 'S' { $weight = 32.06; }
>>  ;
>> DIGITS : ('0'..'9');
>>
>> How could I embed a simple counter? For the beginning I would be  
>> happy to sum up the weights ignoring the digits (e.g. H20 =>  
>> 17.00694) How can I display the result of the calculations in the  
>> debug environment?
>>
>> For any help I would be gladful!
>>
>> Regards,
>> Toby
>>
>>
>> List: http://www.antlr.org/mailman/listinfo/antlr-interest
>> Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-email-address
>>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.antlr.org/pipermail/antlr-interest/attachments/20090409/3ceafbb3/attachment.html