Category:Fexl: Difference between revisions

For example, here is the C routine which implements the classic '''S''' combinator (fusion), where (S x y z) = (x z) (y z):

 

{

if (!f->L->L || !f->L->L->L) return f;

return A( A(f->L->L->R, f->R), A(f->L->R, f->R) );

 

Fexl functions may have side effects -- after all, they've gotta happen '''somewhere'''. For example here's the implementation of the char_put function, called as (char_put ch next), which prints the single character ch to stdout and then continues with next:

 

{

if (!f->L->L) return f;

putchar(get_long(x));

return f->R;

 

Fexl is very free-wheeling about side effects, because of course they must happen '''somewhere'''. But you the Fexl programmer can easily isolate and confine side effects as diligently as you like, factoring them out systematically, applying monadic techniques, or whatever.