[cfe-dev] Source rewrite

[Abramo Bagnara]

Il 17/12/2009 16:57, Douglas Gregor ha scritto:
> 
> On Dec 17, 2009, at 5:23 AM, steve naroff wrote:
> 
>>
>> On Dec 17, 2009, at 7:05 AM, Abramo Bagnara wrote:
>>
>>> In an application that uses clang libraries we need to transform some
>>> specially written comments in C construct.
>>>
>>> e.g:
>>> int p() {
>>> int a = 3;
>>> /* #instrument(a)# */
>>> }
>>>
>>> should be parsed as
>>> int p() {
>>> int a = 3;
>>> instrument(a);
>>> }
>>>
>>> I've added a CommentHandler to Preprocessor to catch comments and I
>>> thought to use Rewriter class to manipulate the input buffer inserting
>>> after the comment the text to be parsed, but then I've realized that
>>> Rewriter class is not designed to rewrite lexer input buffers, but to
>>> build a separate object where original text and changes live together.
>>>
>>> Now I'm a bit confused: what's the proper way to cope with the need
>>> described above?
>>>
>>
>> Hi Abramo,
>>
>> The ASTContext class has a 'Comments' member that contains all the  
>> SourceRanges's for all comments in the source file.
>>
>> This assumes you've told the preprocessor to keep comments.
> 
> You actually don't have to tell the preprocessor to keep comments; it
> keeps the source ranges for the comments regardless, and you can go back
> to the source to get the content of the comments.

I think to have explained badly what we need: I've no problems to get
the comment content, my problem is to translate, during the parsing, the
comment content in another text to be lexed/parsed instead of (or just
after) the comment.

As I write above, what I need is that the AST built from:

int p() {
  int a = 3;
  /* #instrument(a)# */
}

is as if the source read was:

int p() {
  int a = 3;
  instrument(a);
}