DSL EXPRESSION:
subr s() {x=1}


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]
                "=" [tt:equals] [nt:Assignment]
                    "x" [tt:non_sigil_name] [nt:LocalVariable]
                    "1" [tt:int_literal] [nt:int_literal]

