[plt-scheme] Swindle: defgeneric arity

From: Joe Marshall (jmarshall at alum.mit.edu)
Date: Fri May 26 12:45:09 EDT 2006

The dotnet API to Common Larceny is based on Swindle and it needs to
support methods of varying arity.  I added an <arity-overload> metaclass
that dispatches on arity first, then the normal dispatch second.
Generic functions
are transformed to arity-overload functions when necessary.

Look in lib/mzscheme/dotnet.sch file in the Common Larceny release.

On 5/26/06, Eli Barzilay <eli at barzilay.org> wrote:
> On May 25, Doug Orleans wrote:
> > I'm just getting my feet wet with Swindle, and noticed that you
> > can't have two methods with different arity on the same generic.  Is
> > there a deep implementation (or design) reason for this, or is this
> > just something left over from the CLOS tradition?
> >
> > (I realize I can probably use the MOP to make multiple-arity
> > generics, but I'm not sure it's worth it...)
> I tried that at the time, but IIRC it made things too complicated.  It
> should be possible as long as all arities are distinguishable (maximum
> of one `rest' arity, and all other arities smaller than that), but the
> implementation is not going to be fun.
> --
>          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
>                  http://www.barzilay.org/                 Maze is Life!
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