Re: [Boost-users] [preprocessor] removing parentheses

On 8/4/2010 7:07 PM, John B. Turpish wrote:

On Wed, Aug 4, 2010 at 4:05 PM, Edward Diener wrote:

...

I have a single macro parameter which allows its passed value to contain commas. Therefore the user of the macro needs parentheses around the parameter if it contains one or more commas ( to does not have to ). When processing this parameter in a macro I would like to remove the outer parentheses if they are there before passing the value on for further processing. Is there a way to do this using some preprocessor library macro ?

Have you considered using a variadic macro? I hear they're not available for all C++ precompilers, but it may do what you want: Instead of #define YOUR_MACRO( NOCOMMASALLOWED ) NOCOMMASALLOWED you might use #define YOUR_MACRO( ... ) __VA_ARGS__ I know it's only "one" argument you're after, but this would at least pull the commas through in-tact.

Variadic macros would indeed be a solution if the compiler(s) I am using supported that feature. But I am really trying to do work for inclusion into Boost itself and very few compilers support variadic macros as yet.