Re: proper tail recursion for gcc

[Mikael Djurfeldt]

Michael Livshin <address@hidden> writes:

> no, the continuation must expect the precise number of values that is
> returned.
> 
> [ in fact, it seems that the Scheme multiple-value return facility
>   tries hard to conceptually unify function calls and value returns,
>   i.e. a return is just a call to a continuation. ]

Yes, this is an important point.

> > I don't know, but Common Lisp does require this.  To make multiple value
> > returning compatible with an ordinary call probably requires a new
> > compiler feature.  At least I don't see a clean way to do that without
> > adding a compiler feature.
> 
> well, I'm sure CL hackers out there would very much appreciate GCC
> taking care of them too ;).

The Dybvig paper discusses an extension which supports the CL style,
but it requires more work, and if we are after maximum efficiency, it
also requires a different user interface in GCC.