Re: CL implementation questions

[Per Bothner <per at bothner dot com>]

On 04/08/2012 11:18 PM, Helmut Eller wrote:
> * Charles Turner [2012-04-08 21:41] writes:
>
> > In CL:
> >
> > #|kawa:1|# ((as<pair>  '(1 2 3)):getCar)
> > Invalid parameter, was: gnu.lists.PairWithPosition cannot be cast to
> > gnu.mapping.Procedure
> > java.lang.ClassCastException: gnu.lists.PairWithPosition cannot be
> > cast to gnu.mapping.Procedure
> > ...
> > #|kawa:2|# (as<pair>  '(1 2 3)):getCar
> > (1 2 3) :getCar
> >
> > I'm struggling to see where the difference is happening. I don't know
> > how to trace the execution since the difference is happening in
> > ModuleExp thread which I don't know how to get a handle on for the
> > debugger.
> >
> > Any ideas?
>
> The difference is probably in the reader: ":foo" in CL syntax is the
> keyword foo.  In Kawa/Scheme that's written as "foo:" and x:foo is infix
> syntax for ($lookup$ x (quasiquote foo)).  CL doesn't have that infix
> stuff.

Yes.  Common Lisp uses colon for a package prefix of a compound symbol,
and it's unclear how that should interact with colon notation or other
short-hands.  I suggest using the procedures invoke and invoke-static, 
rather
than using colon notation.  We might consider some kind of abbreviated
syntax for Common Lisp, but let's not worry about that for now.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/