In Cat I wanted to inline every single function call. Essentially I wanted to replace functions with macros. Ideally the whole language would be based on a series of rules for rewriting the syntax (more on this in a future installment).

The single challenge I faced with this approach was how to deal with recursion. Macros do not allow recursion. I believe I found the answer: goto.

Consider the following psuedo-code in Cat (the code is "psuedo-code" because it uses an old version of Cat syntax, the new form is extremely cryptic and will possibly be revereted to this form again):

  define a = b [a] [c] if;

  define a = #a label b [#a goto] [b] if;

Am I missing anything here, or is this sufficient?

: fib ( n -- n )
  dup 0 = if return then
  dup 1 = if return then
  dup 1- fib swap 2- fib + return
;

> : fib ( n -- n )
>   dup 0 = if return then
>   dup 1 = if return then
>   dup 1- fib swap 2- fib + return
> ;
>