Can you capitalize a pasted token in a macro?

Question

In a C macro, is it possible to capitalize a pasted-in token? For example, I currently have the following macro:

#define TEST(name, keyword) \
    test_##name:
        TEST_##keyword##_KEYWORD

I would invoke this as follows:

TEST(test1, TEST1)

which would yield the following:

test_test1:
    TEST_TEST1_KEYWORD

Now, instead of having to type the same name twice (once with all lower case characters, and again with all upper case characters), is there any way that I could do either of the following, and either change the token into all uppercase letters or all lowercase letters?

TEST(test1) or TEST(TEST1)

Thanks, Ryan

Answer 1

As fat as I'm aware, the only operations that can be done on tokens in the C preprocessor (at least ISO/ANSI standard) is to replace, 'stringify' or concatenate them. I'm also unaware of any GCC or MSVC extensions that will let you do what you want.

However, people have been coming up with clever (or oddball) ways to do magical (or horrible) things with macros, so I wouldn't be surprised if someone surprises me.

Answer 2

You could do something like the following (untested, probably typos...)

#define NORMALIZE(TOK) NORMALIZE_ ## TOK

and then for each of the writings that may occur do

#define NORMALIZE_test1 test1
#define NORMALIZE_TEST1 test1

then use the NORMALIZE macro inside your real macro something like

#define TEST(name, keyword)                    \
    test_ ## NORMALIZE(name):                  \
        TEST_ ## NORMALIZE(keyword) ##_KEYWORD

(but maybe you'd have to do some intermediate helper macros until you get all concatenations right)