我在 ANTLR 中使用词法分析器规则手动发出令牌时遇到了一些麻烦。我知道需要使用 emit() 函数，但似乎明显缺乏关于此的文档。有人有一个很好的例子来说明如何做到这一点吗？
ANTLR 书提供了一个很好的示例，说明如何解析 Python 的嵌套。例如，如果您看到一定数量的空白大于前一行的空白，则发出 INDENT 标记，但如果小于，则发出 DEDENT 标记。不幸的是，这本书掩盖了所需的实际语法。
编辑：这是我试图解析的示例。这是 Markdown 的嵌套块引用：
before blockquote
> text1
>
> > text2
>
> text3
outside blockquote
现在，到目前为止我的方法基本上是计算 > > 。每行符号。例如，上面的内容似乎应该发出（大致...）PARAGRAPH_START、CDATA、PARAGRAPH_END、BQUOTE_START、CDATA、BQUOTE_START、CDATA、BQUOTE_END、CDATA、BQUOTE_END、PARAGRAPH_START、CDATA、PARAGRAPH_END。这里的困难是最终的 BQUOTE_END ，我认为它应该是在找到非块引用元素后发出的虚构令牌（并且嵌套级别 >= 1）
I'm having a bit of trouble manually emitting a token with a lexer rule in ANTLR. I know that the emit() function needs to be used but there seems to be a distinct lack of documentation about this. Does anybody have a good example of how to do this?
The ANTLR book gives a good example of how you need to do this to parse Python's nesting. For example, if you see a certain amount of whitespace that's greater than the previous line's whitespace, emit an INDENT token but if it's less, emit a DEDENT token. Unfortunately the book glosses over the actual syntax that's required.
EDIT: Here's an example of what I'm trying to parse. It's Markdown's nested blockquotes:
before blockquote
> text1
>
> > text2
>
> text3
outside blockquote
Now, my approach so far is to essentially count the > symbols per line. For example, the above seems like it should emit (roughly...) PARAGRAPH_START, CDATA, PARAGRAPH_END, BQUOTE_START, CDATA, BQUOTE_START, CDATA, BQUOTE_END, CDATA, BQUOTE_END, PARAGRAPH_START, CDATA, PARAGRAPH_END. The difficulty here is the final BQUOTE_END which I think should be an imaginary token emitted once a non-blockquote element is found (and the nesting level is >= 1)
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好吧，如果您想要发出的标记不是由词法分析器规则定义的，那么您需要添加一个标记部分，如下所示：
在您的词法分析器中，您仍然需要一个规则来告诉词法分析器何时生成此标记。一个常见的例子是确定某个东西是整数、范围还是实数值。
在这里你可以看到我们匹配一个 INT，然后向前看，如果我们找到一个双句点，那么我们就知道 INT 确实是一个 int，而不是一个实数。在本例中，我们将变量 _ttype 设置为 INT。如果我们找到一个句号，然后找到一个“e”，我们就知道它是一个真实的。
在第二种情况下，我们匹配一个句点，我们知道如果下一个字符是一个句点，那么我们就得到了一个范围，否则我们得到了一个实数。
如果合适的话，我们可以使用上面定义的 MYFAKETOKEN 类型来分配给 _ttype。
Well if the token you want to emit is not defined by a lexer rule then you'll need to add a token section like so:
In your lexer you will still need a rule that tells the lexer when to produce this token. A common instance is determining if something is an Integer or range or real value.
Here you can see we match either an INT and then lookahead, if we find a double period then we know that the INT is really an int and not a real. In this case we set the variable _ttype to be INT. If we find a PERIOD and then an 'e' we know it's a real.
The second case where we match a period we know that if the next char is a period, then we've got a range otherwise we've got a real.
We could use the
MYFAKETOKENtype we defined above to assign to _ttype if that was appropriate.好的，我做了一些研究，发现了这个： http: //www.cforcoding.com/2010/01/markdown-and-introduction-to-parsing.html
我认为 ANTLR 并不是真正为此类任务而设置的，并且试图竭尽全力去做这真的不值得。
Okay, I did some research and found this: http://www.cforcoding.com/2010/01/markdown-and-introduction-to-parsing.html
I don't think ANTLR is really set up for this sort of task and trying to bend over backwards to do it isn't really worth it.