[antlr-interest] Tree construction for function / method calls

[Christian Pontesegger]

Hi all,

sorry for the porevious mail, webmail messed it up ...


I am desperately trying to create a tree for method calls but am struggling with recursion in the tree generation. My language allows for statements like this:

        print().foo().test().me()

        Where print() is a function returning an object. Then subsequently methods are called.

        $x.this().is().it()

        Where $x is a variable holding an object.

Previous two statements should be transformed to trees like this:

        ^(^(METHOD ^(METHOD ^(FUN print) foo) test) me)


        ^(^(METHOD ^(METHOD ^(VAR x) this) is) it)


So I started with a grammar, but got stuck here:


grammar Test;

options {
  language = Java;
  output = AST;
  ASTLabelType=CommonTree;
}

tokens {
        VAR;
        FUN;
        METHOD;
}

program
        : statement* EOF!
        ;

statement
        :       token
                (
                        '.' IDENT '(' ')'       -> ^(METHOD token IDENT)
                )*
        ;

token
        :       function
        |       variable
        ;


function
        :       IDENT   '(' ')'                 -> ^(FUN IDENT)
        ;

variable
        :       '$' IDENT                               -> ^(VAR IDENT)
        ;

fragment LETTER : ('a'..'z' | 'A'..'Z');
fragment DIGIT : '0'..'9';
fragment LINEBREAK : '\r'? '\n';
IDENT : LETTER (LETTER | DIGIT | '_')*;
WHITESPACES : (' ' | '\t' | '\f' | LINEBREAK)+ { $channel = HIDDEN; };





Running this grammar on the example input results in following tree:
(METHOD (FUN print) foo) (METHOD (VAR x) this)


I see that I need to change the * from "statement" to ? somehow, but how can I call statement recursively?

Thanks
Christian
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