[antlr-interest] implementing 'if' and 'while' grammar with actions

[Abhijit Nandkumar Ghonge]

Hi,

I managed to skip the statements for "if" statement implementation using stack concept. Now, I want to implement looping in "while" statement. My rule for while statement is:

whilestatement:
                        'while' LPAREN expr RPAREN 'do' NEWLINE
                        {
                                    //action to push the outcome of expr on stack
                        } statement* done
                        {
                                    // peep the top of the stack
                                    // if expr is true reposition the line number of parser to start of while statement
                                    // else pop the top of the stack and continue ahead
                        }

I'm stuck at the logic to be put for the bold comments above. Is there something like yylineno as in yacc parser, which, if I set the line number of while statement, it loops back?

Please help.

Regards,
Abhijit.



________________________________
From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-bounces at antlr.org] On Behalf Of Abhijit Nandkumar Ghonge
Sent: Thursday, August 23, 2007 6:19 PM
To: antlr-interest at antlr.org
Subject: [antlr-interest] implementing 'if' and 'while' grammar with actions
Importance: High

Hi all,

I want to implement parser grammar for 'if' and 'while' statement with actions in it.
My script is :

var1=10
if ( var1 < 9 ) then
var1++
print (var1)
endif

How do I skip the execution of the statements if the "if-condition" is false as in the above case?

I searched for the grammar implementation in the site, but all examples where implementing grammar rules for "if" and "while" without actions in them. I want to embed actions in the grammars.
Please give some pointers to "if" or "while" grammar implementation with actions in it.
Please Help.

thanks,
Abhijit
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