如何查找是否以及不带括号的语句？ [英] How can I find if and for statements without braces?

问题描述

我正在寻找一个项目，其中某些 if 和 for 语句没有相关的括号，像这样：

I'm looking at a project in which some if and for statements do not have their associated brackets, like so:

if(condition)
  single_line_statement;
for(int i=0;i<10;i++)
  single_line_statement;

我想找到这些语句！

但是，由于存在两种不同的包围样式的代码，这变得具有挑战性：

However, this is made challenging by the existence of code with two different bracketing styles:

if(condition){
   stuff;
}

和

if(condition(a) && condition(b))
{
  stuff;
}

以及复杂的语句，例如（请注意嵌套的括号）：

as well as by complex statements such as (note the nested brackets):

for (auto const &x : y)
{
    for (auto const &m : ted.bob())
    {
        if (m.n(o) != 0)
        {
            p[q] = true;
        }
        r["s"].push_back(rn.t(u));
    }
}

如何找到 if 和用于没有括号的语句？

推荐答案

为解决这个问题，我创建了一个方便的丹迪脚本：

To solve this problem, I created a handy dandy script:

#!/bin/bash
find . -name '*.h' -o -name '*.cpp' | #Find all C++ files
  xargs pcregrep -A 1 -nHM '\b(?:if|for)\s*(\(([^()]++|(?1))*\))(?!.*{|.*\n.*{)'

这将查找所有C ++文件，然后使用与Perl兼容的正则表达式将它们作为单个长行检查每个文件的内容。此表达式使用递归（？1）提取 if <后的（条件）。 / code>和用于语句和。字符以匹配不是换行符的字符和 \n 常量以匹配新行。负向超前（？！...）用于查找不带括号的行。

This finds all the C++ files and then examines the contents of each file as a single, long line using a Perl Compatible Regular Expression. This expression uses recursion (?1) to extract the (condition) following the if and for statements and the . character to match characters which are not newlines and the \n constant to match new lines. Negative-lookahead (?!...) is used to find the lines without braces.

正则表达式可以在此处进行在线测试。

The regular expression can be tested online here.

输出看起来像这样：

./dir1/file1.cpp:845:        if (!a)
./dir1/file1.cpp-846-            std::cout << "a not found!" << std::endl;
--
./dir2/file2.cpp:20:    if (b == NULL)
./dir2/file2.cpp-21-        throw std::runtime_error("b was NULL");

由于脚本实际上并不解析C ++，因此在某些情况下它会表现异常。例如，它将丢失：

Since the script does not, in fact, parse C++, there are situations where it will misbehave. For instance, it will miss this:

if (condition) // An example {
  statement;

此答案利用 clang-tidy 来提供完整的支票，但必须合并 clang-tidy 进入一个人的构建系统。

This answer leverages clang-tidy to provide a complete check, at the cost of having to incorporate clang-tidy into one's build system.

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