Treetop/PEG中的非贪婪匹配? [英] Non-greedy matching in Treetop/PEG?

问题描述

我该如何在Treetop中做类似的事情?

How would I do something like this in Treetop?

/.+?;/

似乎唯一的方法是这样做:

It seems like the only way is to do:

[^;]+ ';'

还有什么丑陋的..其他方式吗? .+?似乎不起作用.

Which is kind of ugly.. any other way? .+? doesn't seem to work..

推荐答案

默认情况下，PEG是贪婪和盲目的，这意味着它们会尽可能多地吃掉它们的输入，并且他们不考虑随后发生的事情:

PEGs are greedy and blind by default, that means they eat as much input as they can and they do not consider what comes afterwards:

S <- P1* P2(贪婪，盲目)

尽管可以通过使用有序选择(并且无需使用先行提示)来解决该问题，但相当容易:

That can be considerably easy fixed though by making use of the ordered choice (and without using lookaheads):

S <- P1 S / P2(贪婪，非盲目)

S <- P2 / P1 S(懒惰，非盲)

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