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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a need for a function that will do macro substitution in a string.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This is for the modularize tool I am trying to enhance to show where preprocessor conditional directives’ condition expressions differ in different instances of preprocessing a header. I use a PPCallbacks-derived class to track the #if/#elif/#ifdef/#ifndef
directives. The callback function arguments include a SourceRange. I can use that to get the unpreprocessed source snippet for the condition expression. I want to take either that source snippet or the SourceRange and get a string that has had any macros
in the unpreprocessed source snippet expanded, including function-style macros. White space is not important, as it just needs to be consistent. I do a comparison of the macro-expanded condition strings to find out if an instance of a header differs from
other instances.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In looking at the Preprocessor class, I didn’t see such a function. In thinking about how it might be done, because this is to be done in the context of a PPCallbacks callback call, I’m thinking there might be the potential for problems
with interfering with the preprocessor or lexer state. Therefore my current thinking is that I probably will need to instantiate a separate Lexer, and probably a separate Preprocessor too, with the Preprocessor linked to the original preprocessor so it can
find the macro definitions. (There seems to be a pointer for this in Preprocessor.) The pragma mode in Lexer seems comparable, but I don’t want the raw lexing mode, so I’d probably need a new constructor that lets me set the buffer pointers and the right
mode settings. Also, I probably don’t want the Preprocessor to be calling PPCallback callbacks such as the MacroExpanded callback.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Could someone point me to existing code that could do this, or otherwise help me get the information or code I need to do this?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-John<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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