Treetop：获取节点的偏移量

发布于 2024-10-01 05:06:17 字数 882 浏览 2 评论 0原文

我正在使用 Treetop 为小型编程语言生成解析器。

解析成功后，我想对语法树进行一些语义分析。理想情况下，每当我遇到一段（语义上）无效的代码时，我想打印出一条错误消息，其中包括发生错误的行。我知道这是可能的，因为如果我这样做，

parser = MyParser.new
tree = parser.parse("foobar")
p tree

我会得到类似的内容

SyntaxNode offset=0, "foobar":
    SyntaxNode offset=0, "f"
    SyntaxNode offset=1, "o"
    SyntaxNode offset=2, "o"
    SyntaxNode offset=3, "b"
    SyntaxNode offset=4, "a"
    SyntaxNode offset=5, "r"

本质上，我想要一种访问给定 SyntaxNode 对象（或其子类）的 offset 属性的方法。不幸的是，根据 http://treetop.rubyforge.org/semantic_interpretation.html 唯一可用的方法Treetop::Runtime::SyntaxNode 上有 terminal?、nonterminal?、text_value 和 elements< /code>，所以似乎没有内置的方法可以做到这一点。

原文

I'm using Treetop to generate a parser for a small programming language.

Upon successful parsing, I'd like to do some semantic analysis on the syntax tree. Ideally, whenever I encounter a piece of (semantically) invalid code, I would like to print out an error message that includes the line where the error occurred. I know this is possible because if I do

parser = MyParser.new
tree = parser.parse("foobar")
p tree

I get something like

SyntaxNode offset=0, "foobar":
    SyntaxNode offset=0, "f"
    SyntaxNode offset=1, "o"
    SyntaxNode offset=2, "o"
    SyntaxNode offset=3, "b"
    SyntaxNode offset=4, "a"
    SyntaxNode offset=5, "r"

Essentially, I'd like a way to access the offset attribute of a given SyntaxNode object (or subclass thereof). Unfortunately, according to http://treetop.rubyforge.org/semantic_interpretation.html the only methods available on Treetop::Runtime::SyntaxNode are terminal?, nonterminal?, text_value and elements, so there doesn't seem to be a built-in way of doing this.