DSL EXPRESSION:
subr s() {return 2}


AST:
"block" [tt:block] [nt:StatementBlock]
    "s" [tt:non_sigil_name] [nt:SubroutineDefinition]
        "params" [tt:params] [nt:ParameterList]
        "block" [tt:block] [nt:StatementBlockInBraces]
            "block" [tt:block] [nt:StatementBlock]
                "return" [tt:kw_return] [nt:ReturnStatement]
                    "2" [tt:int_literal] [nt:int_literal]

