[antlr-interest] VB If elseif end if?

[Anakreon]

ronald.petty at milliman.com wrote:
> 
> I have in my Parser the rule
> 
> //don't forget s1:s2:s3 etc for "If x Then s1:s2..." and for general use
> statement
>         :       {System.out.println("Entered Statement:Declaration");}
>                 (declaration)=>declaration
>                 {System.out.println("Leaving Statement:Declaration");}
>         |       {System.out.println("Entered Statement:Expr");}
>                 expr
>                 {System.out.println("Leaving Statement:Expr");}
>         |       {System.out.println("Entered Statement:IF");}
>                 IF expr THEN (statement)* (ELSEIF expr THEN 
> (statement)*)* (ELSE (statement)*)? (END IF)?
>                 {System.out.println("Leaving Statement:IF");}
>         ;
> 
> And for newlines in the lexer
> 
> NL
>         :
>         (       ("\r\n") => "\r\n"
>         |       '\r'
>         |       '\n'
>         )+
>         { newline(); _ttype = Token.SKIP; }
>         ;
> 
> If I have the input
> 
> if x then y
> if x then y
> 
> The result is valid according to my grammar.  However instead of two "if 
> then" statements I have one "if" with another shoved in the tail end of 
> the statement.
> 
> (hope this is good syntax)
> 
> statement
> if (start of statement input)
> x = expr (for now just an identifier)
> then (next part of the expression
> y = statement (which is an expr, just an identifier)
> now sense we are looping in the statement (statement)*
> the next if x then y is starting there instead of a top level statement.
> 
> This is because in VB the newline after y means your done.  However I 
> eat all newlines in the lexer.  What are the possible ways around this?
> 
> Thanks for the pointers.
> Ron
New lines are significant in VB.
For this reason the lexer I implemented eats new lines if the last token given 
was '_' or a new line.The last token which the lexer served to the parser is 
stored in a variable.




 
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