DSL EXPRESSION:
func f(a,b,){return 1}


AST:
"block" [tt:block] [nt:StatementBlock]
    "f" [tt:non_sigil_name] [nt:NamedFunctionDefinition]
        "params" [tt:params] [nt:ParameterList]
            "params" [tt:params] [nt:ParameterList]
                "a" [tt:non_sigil_name] [nt:Parameter]
                    "a" [tt:non_sigil_name] [nt:LocalVariable]
                "b" [tt:non_sigil_name] [nt:Parameter]
                    "b" [tt:non_sigil_name] [nt:LocalVariable]
        "block" [tt:block] [nt:StatementBlockInBraces]
            "block" [tt:block] [nt:StatementBlock]
                "return" [tt:kw_return] [nt:ReturnStatement]
                    "1" [tt:int_literal] [nt:int_literal]

