CPP: Escaping macro identifiers - c++

Question

Is there a way to escape macro names (identifiers) in a c pre processor (cpp) ?
I want to conditionalize some web code (html, css...) with readable macro names.
Example for a conditional css file:
/*root*/
some rootcode
#if height==480
/* height 480 */
.page {
line-height:23px;
}
#elif height<480
/* height < 480 */
.page {
line-height:46px;
}
#endif
An invocation of
cpp -P -D height=480 -oout.css css.ccss
results in (after deleting newlines)
some rootcode
.page {
line-480:23px;
}
but "line-480" is wrong.
Is there a way to escape "height" in the code without changing the macro name or stringify it?

Answer 1

You can either:
1) undefine the macro:
#undef height
2) rename the macro using standard-like caps:
#define HEIGHT
3) Use guards before processing the file:
#if height==480
#define HEIGHT_480
#undef height
#endif
#if height>480
#define HEIGHT_OVER_480
#undef height
#endif
/*root*/
some rootcode
#if HEIGHT_480
/* height 480 */
.page {
line-height:23px;
}
#elif HEIGHT_OVER_480
/* height < 480 */
.page {
line-height:46px;
}
#endif
The first one loses information after the undefine. The second one is impractical if there's extensive use of the macro.
The third one is the best option IMO. I've seen it used in production code where stuff like this was necessary.

Answer 2

I played with the idea of Luchian Grigore to undefine used filenames and I found a (nearly) general solution for this problem:
including a "define.file" at the begin of the conditionals and a "undefine.file" after the given condition.
So the problem is reduced to two macro names, that have to stay: DEFINEFILE und UNDEFINEFILE. But this two macros could be encrypted with their hashcode or with a randomname to avoid a use of this names in the conditional text.
The "define.file":
#define height 480
#define os 1
The "undefine.file"
#undef height
#undef os
the "conditionalcss.ccss"
/*root*/
some rootcode
#include __DEFINEFILENAMEPATH__
#if height==480
#include __UNDEFINEFILENAMEPATH__
/* height 480 */
.page {
line-height:23px;
}
#include __DEFINEFILENAMEPATH__
#elif height<480
#include __UNDEFINEFILENAMEPATH__
/* height > 480 */
.page {
line-height:46px;
}
#include __DEFINEFILENAMEPATH__
#endif
#if os==1
#include __UNDEFINEFILENAMEPATH__
os is windows (if 1 refers to windows)
and height also undefined i hope
#endif
Finally the cppcall with the parametric define and undefine files:
cpp -P -D __DEFINEFILENAMEPATH__="\"define.file\"" -D __UNDEFINEFILENAMEPATH__="\"undefine.file\"" -oout.css css.ccss
With this idea, the restulting "out.css" looks like:
some rootcode
.page {
line-height:23px;
}
os is windows (if 1 refers to windows)
and height also undefined i hope
This solution has only the disadvantages of two macros and a possible poor performace because of the multiple imports.
I hope it helps other people to solve their problem.
Greetz
Adreamus