Re: [stack] language hierarchy

On Dec 10, 2007, at 7:30 PM, William Tanksley, Jr wrote:

>> You would have problems in Cat  because of the fact that you can't  
>> write:
>> 1 2 [define f { 3 4 }]
>
> Clearly, the 'define' part of Cat is not itself concatenative. That's
> okay; Joy has a non-concatenative superset. So does every other
> practical concatenative language. The only way around that is to use
> dynamically scoped definitions.

The language I'm working on has define (spelled 'def') as a normal  
function with type "A (B -> C) sym -> A". This allows one to define  
new functions without special syntax:

	(sqr swap sqr + sqrt) :hypot def

This has the downside that functions cannot make use of explicit  
recursion (as hypot isn't defined until def is called, and hence the  
quote can't make use of it), but this restriction is in place anyway  
due to the type system.

- John