Question

So I have a rule for statement which can lead to more statements:

statement returns[String txt]
    :   '{'{
            $txt="{";
        }
        (statement{
            $txt+=$statement.txt;
        })*
        '}'{
            $txt+="}";
        }
    | ... //more rules // ...
    ;

I am getting

reference $statement is ambiguous; rule statement is enclosing rule and referenced in the production (assuming enclosing rule)

but don’t know how to resolve it. Somehow I would need to tell ANTLR that I need the return txt of statement inside parent statement. Please help me out 🙂

Answer 1

If you use $statement, ANTLR doesn’t know if you mean the rule itself, or the statement inside ( ... )*.

Try something like this:

statement returns[String txt]
    :   '{'{
            $txt="{";
        }
        (s=statement{
            $txt+=$s.txt;
        })*
        '}'{
            $txt+="}";
        }
    | ...
        ;