Programmatically parse and edit C++ Source Files

Question

Hi,

I want to able programmatically parse and edit C++ source files. I need to be able to change/add code in certain sections of code (i.e. in functions, class blocks, etc). I would also (preferably) be able to get comments as well. Part of what I want to do can be explained by the following piece of code:

CPlusPlusSourceParser cp = new CPlusPlusSourceParser(“x.cpp”);  // Create C++ Source Parser Object
CPlusPlusSourceFunction[] funcs = cp.getFunctions();  // Get all the functions

for (int i = 0; i &lt funcs.length; i++) {  // Loop through all functions
    funcs[i].append(/* … code I want to append …*/);  // Append some code to function 
}
cp.save(); // Save new source
cp.close(); // Close file

How can I do that? I’d like to be able to do this preferably in Java, C++, Perl, Python or C#. However, I am open to other language API’s.

Answer 1

Very interesting idea. One, less than easy option (just due to the complexity of regex's) would be to utilize regular expressions in any of the languages you suggested. It wouldn't be too difficult to identify what is a function, what is variable definition/declaration, etc. It would take some experience with regexes to get it just right, but I think that would do exactly what you're looking for with minimal code.

Answer 2

You can use any parser generator tool to generate a c++ parser for you, but first you have to get the CFG (context free grammar) for C++ , check Antlr

Edit:

Also Antlr supports a lot of target languages

Answer 3

You need a working grammar and parser for C++ which is, however, not too easy as this can't be constructed with most parser generators out there. But once you have a parser you can actually take the abstract syntax tree of the program and alter it in nearly any way you want.

Answer 4

have a look at the doxygen project, its a open source project, to parse and document several programming languages, C++ included. I believe using this project's lexer will get you more than half the way

Answer 5

This is similar to http://stackoverflow.com/questions/239722/ast-from-c-code

If your comfortable with Java antlr can easily parser your code into an abstract syntax tree, and then apply transformation to that tree. A default AST transform is to simply print out the original source.

Answer 6

The Mozilla project has a tool that does this.

Answer 7

In a C# -- or general .net -- approach, you might be able to get some use out of the C++/CLI CodeDOM provider -- having not used the C++ version of this type, I don't know how well it would handle code that is template heavy.

Answer 8

A robust C++ parser is available with the DMS Software Reengineering Toolkit. It parses a variety of C++ dialects including ANSI, GNU 3/4, MSVS6 and MSVisual Studio 2005 and managaged C++.

It builds ASTs and symbol tables (the latter is way harder than you might think). You can navigate the ASTs, transform into different valid C++ programs, and regenerate code including comments.