使用flex / yacc编写C ++编译器需要多少时间？ [英] How much time would it take to write a C++ compiler using flex/yacc?

问题描述

使用lex / yacc编写C ++编译器需要多少时间？

How much time would it take to write a C++ compiler using lex/yacc?

在哪里可以开始使用？

推荐答案

有很多解析规则不能由bison / yacc解析器解析（例如，在某些情况下区分声明和函数调用）。另外有时，令牌的解释需要来自解析器的输入，特别是在C ++ 0x中。例如，处理字符序列>> 极其依赖于解析上下文。

There are many parsing rules that cannot be parsed by a bison/yacc parser (for example, distinguishing between a declaration and a function call in some circumstances). Additionally sometimes the interpretation of tokens requires input from the parser, particularly in C++0x. The handling of the character sequence >> for example is crucially dependent on parsing context.

这两个工具是解析C ++的非常差的选择，你将不得不放入很多特殊情况下逃避这些工具依赖的基本框架，以正确解析C ++。它会花费你很长时间，即使你的解析器可能会有奇怪的错误。

Those two tools are very poor choices for parsing C++ and you would have to put in a lot of special cases that escaped the basic framework those tools rely on in order to correctly parse C++. It would take you a long time, and even then your parser would likely have weird bugs.

yacc和bison是 LALR（1）解析器生成器，它们不够复杂，不能有效地处理C ++。正如其他人已经指出的，大多数C ++编译器现在使用递归下降解析器，以及其他几个

yacc and bison are LALR(1) parser generators, which are not sophisticated enough to handle C++ effectively. As other people have pointed out, most C++ compilers now use a recursive descent parser, and several other answers have pointed at good solutions for writing your own.

C ++模板不适用于处理字符串，即使是常量（虽然这可能固定在C ++ 0x，我没有仔细研究），但如果他们是，你可以很容易地编写一个递归下降解析器在C ++模板语言。我觉得很有趣。

C++ templates are no good for handling strings, even constant ones (though this may be fixed in C++0x, I haven't researched carefully), but if they were, you could pretty easily write a recursive descent parser in the C++ template language. I find that rather amusing.

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