编译/解析有意义的空白
你好，我正在寻找一种伪 Markdown 类型的语言和一个解析器来将其解析为 xhtml。
我从未编写过编译器...我简单地了解了 ANTLR，并且想知道 ANTLR 是否可以处理具有有意义的空格的解析？
所以说我有这样的东西：
some text
some other text
# bullet point
# nested bullet point
根据上下文和前缀空格的数量，这些行将意味着不同的事情。
为此编写解析器有什么好工具？
谢谢， 亚历克斯
Hi I'm looking to make a pseudo Markdown kind of language and a parser to parse it into xhtml.
I've never written a compiler... I've taken brief looks at ANTLR and am wondering if ANTLR can handle parsing things with meaningful whitespace?
So say I have something like this:
some text
some other text
# bullet point
# nested bullet point
Depending on context and number of prefixing spaces, those lines would mean different things.
What is a good tool to use to write a parser for this?
Thanks,
Alex
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ANTLR 肯定可以用于此目的。但是，如果您对 ANTLR 或解析器生成器不熟悉，我认为我无法给出如何准确执行此操作的简短解释。我建议您使用 ANTLR 尝试一些简单的操作，并浏览权威的 ANTLR 参考 。它甚至有一段关于此类问题的段落，类似于解析 Python 代码。有关详细信息，请参阅4.3 规则一章的每个 Lexer 规则发出多个令牌段落。
ANTLR can surely be used for this. However, if you're new to ANTLR or parser-generators in general, I don't think I can give a short explanation of how to do this exactly. I recommend you try some simple things with ANTLR and browse through The Definitive ANTLR Reference. It even has a paragraph about this type of problem which is similar to parsing Python code. See Chapter 4.3 Rules, paragraph Emitting More Than One Token per Lexer Rule for details.
我的方法是让你的词法分析器生成缩进/减少缩进标记。存储当前的缩进级别并匹配
\n *等模式。计算空格数，如果与当前缩进级别不同，则发出缩进/减少缩进标记。同样，在行首计算选项卡数。插入一条在
\n[ \t]*模式上抛出错误的规则应该可以阻止人们混合制表符和空格。My approach would be to make your lexer generate indent/outdent tokens. Store the current indentation level and match a pattern like
\n *. Count the number of spaces and if it is different to the current indentation level, emit an indent/outdent token.Similarly, count tabs at start-of-line. Inserting a rule that throws an error up on a pattern of
\n[ \t]*should stop people mixing tabs and spaces.