Macro parameter question

[Brian Alvarez]

 Hello, I would like a macro to generate a certain block of code only if one of the passed parameters is not a literal null. What  can i use to achieve this safely?

 Right now i am using:

Code: [Select]

#if typecodeof(p) <> 0

#endif
 Is this safe? is there a better way? Is it possible?

[Charles Pegge]

Hi Brian,

Typecodeof will work for null, literals and variables but not for parameters consisting of expressions and functions.

[Brian Alvarez]

 I see. Does Typecodeof(null) return 0?

[Charles Pegge]

Yes, but this might be a better option. I am tweaking the match metafunction to support expressions as well as single words:

Code: [Select]

macro mf(p)
#if not match((p),(null))
   print "not null"
#else
   print "null"
#endif
end macro

mf null
mf 0
mf 1/4


[Brian Alvarez]

 Thanks Charles, i will implement it.