解析 C++预处理后的源文件
我正在尝试使用我的自定义解析器（用 c++ 编写）来分析 c++ 文件。在开始解析之前，我想删除所有#define。我希望源文件在预处理后可以编译。因此最好的方法是在文件上运行 C 预处理器。
cpp myfile.cpp temp.cpp
// or
g++ -E myfile.cpp > templ.cpp
[欢迎新建议。]
但由于这个原因，原始行及其行号将丢失，因为文件也将包含所有标题信息，我想保留行号。所以我决定的出路是，
- 在前面添加一个特殊符号 源文件中的每一行（预处理器除外）
- 运行预处理器
- 提取具有该特殊的行 符号并分析它们
例如，一个典型的源文件将如下所示：
#include<iostream>
#include"xyz.h"
int x;
#define SOME value
/*
** This is a test file
*/
typedef char* cp;
void myFunc (int* i, ABC<int, X<double> > o)
{
//...
}
class B {
};
添加符号后，它会像，
#include<iostream>
#include"xyz.h"
@3@int x;
#define SOME value
@5@/*
@6@** This is a test file
@7@*/
@8@typedef char* cp;
@9@
@10@void myFunc (int* i, ABC<int, X<double> > o)
@11@{
@12@ //...
@13@}
@14@
@15@class B {
@16@};
一旦删除所有宏和注释，我将留下数千行，其中几百行将是原始源代码。
这种做法正确吗？我是否遗漏了任何极端情况？
I am trying to analyze c++ files using my custom made parser (written in c++). Before start parsing, I will like to get rid of all #define. I want the source file to be compilable after preprocessing. So best way will be to run C Preprocessor on the file.
cpp myfile.cpp temp.cpp
// or
g++ -E myfile.cpp > templ.cpp
[New suggestions are welcome.]
But due to this, the original lines and their line numbers will be lost as the file will contain all the header information also and I want to retain the line numbers. So the way out I have decided is,
- Add a special symbol before
every line in the source file (except preprocessors) - Run the preprocessor
- Extract the lines with that special
symbol and analyze them
For example, a typical source file will look like:
#include<iostream>
#include"xyz.h"
int x;
#define SOME value
/*
** This is a test file
*/
typedef char* cp;
void myFunc (int* i, ABC<int, X<double> > o)
{
//...
}
class B {
};
After adding symbol it will be like,
#include<iostream>
#include"xyz.h"
@3@int x;
#define SOME value
@5@/*
@6@** This is a test file
@7@*/
@8@typedef char* cp;
@9@
@10@void myFunc (int* i, ABC<int, X<double> > o)
@11@{
@12@ //...
@13@}
@14@
@15@class B {
@16@};
Once all the macros and comments are removed, I will be left with thousands of line in which few hundred will be the original source code.
Is this approach correct ? Am I missing any corner case ?
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您是否意识到 g++ -E 在其输出中添加了一些自己的行，这些行指示原始文件中的行号？您会发现类似的行
表明您正在查看文件 foo.cc 的第 2 行。每当正常的行序列被打乱时，就会插入这些行。
You realize that g++ -E adds some of its own lines to its output which indicate line numbers in the original file? You'll find lines like
which indicate that you're looking at line 2 of file foo.cc . These lines are inserted whenever the regular sequence of lines is disrupted.
过去与 X11 源一起提供的
imake程序使用了一个稍微相似的系统，用@@标记行尾，以便它可以正确地进行后处理。gcc -E的输出通常包含#line指令；您也许可以使用它们来代替您的符号。The
imakeprogram that used to come with X11 sources used a faintly similar system, marking the ends of lines with@@so that it could post-process them properly.The output from
gcc -Eusually includes#linedirectives; you could perhaps use those instead of your symbols.