将正则表达式中的捕获组解析为树的代码 [英] Code to parse capture groups in regular expressions into a tree

问题描述

我需要在正则表达式中标识(可能嵌套)捕获组并创建树.特定的目标是Java-1.6，理想情况下，我希望使用Java代码.一个简单的例子是:

I need to identify (potentially nested) capture groups within regular expressions and create a tree. The particular target is Java-1.6 and I'd ideally like Java code. A simple example is:

((a(b | c)d(e(f * g))h)"

"(a(b|c)d(e(f*g))h)"

将被解析为

"a(b|c)d(e(f*g))h"
... "b|c"
... "e(f*g)"
     ... "f*g"

理想情况下，解决方案应考虑计数表达式，量词等以及转义级别.但是，如果这不容易找到更简单的方法就足够了，因为我们可以限制使用的语法.

The solution should ideally account for count expressions, quantifiers, etc and levels of escaping. However if this is not easy to find a simpler approach might suffice as we can limit the syntax used.

编辑.澄清.我想解析正则表达式字符串本身.为此，我需要了解Java 1.6正则表达式的BNF或等效语言.我希望有人已经做到了.

EDIT. To clarify. I want to parse the regular expression string itself. To do so I need to know the BNF or equivalent for Java 1.6 regexes. I am hoping someone has already done this.

结果的副产品是该过程将测试正则表达式的有效性.

A byproduct of a result would be that the process would test for validity of the regex.

推荐答案

考虑逐步使用实际的解析器/词法分析器: http://www.antlr.org/wiki/display/ANTLR3 /FAQ +-+入门+开始

Consider stepping up to an actual parser/lexer: http://www.antlr.org/wiki/display/ANTLR3/FAQ+-+Getting+Started

它看起来很复杂，但是如果您的语言相当简单，那就很简单了.如果不是这样，那么使用正则表达式执行此操作可能会使您的生活变得地狱:)

It looks complicated, but if your language is fairly simple, it's fairly straightforward. And if it's not, doing it in regexes will probably make your life hell :)

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