[Haskell-cafe] Functions are first class values in C
miguelimo38 at yandex.ru
Sat Dec 22 09:25:26 EST 2007
>> That's not C.
>> That's the C preprocessor, which is a textual substitution macro
> Well, the preprocessor is part of the language in a way. These two
No. In fact, these are even two different programs, see man cpp.
>> Macros certainly aren't first class (you can't pass a macro to a
>> function, only its expansion).
> In Haskell I cannot pass a function to a function, only its expansion.
What do you mean by "expansion"? Can you clarify this?
>> C does support function pointers, which are something like first
>> class functions. The main things C lacks which people associate
>> with true first-class function is:
>> The ability to construct anonymous/local functions.
> If you look at the example you will see I've done that.
No. Your "compose" macro is not a function; for example, you can't
use it as an argument to itself (which is easy in Haskell: (.)(.))
>> The ability to capture local variables and return a function with
>> some variables bound.
> If I can construct "anonymous" functions and "constants", I can
> functions with some variables bound.
See above. You can't.
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