OpenEuphoria

Re: LISP-like expressions

• Posted by "Derek Parnell" <ddparnell at bigpond.com> Mar 04, 2004
• 840 views

----- Original Message ----- 
From: "Andy Serpa" <ac at onehorseshy.com>
To: <EUforum at topica.com>
Subject: RE: LISP-like expressions


> 
> 
> Mike Nelson wrote:
> > 
> > 
> > > I've noticed that there is a striking similarity between Lisp and
> > > Euphoria: Lists and sequences are almost exactly the same thing.
> > >
> > > The only things that Euphoria lacks in order for it to actually by
> > > definition *be* Lisp is functions as first-class objects (meaning,
> > > essentially, that an actual function object can be returned as the
> > > *result* of another function) and the use of the same sequence notation
> > > as standard syntax for everything.
> > >
> > > I just find this really interesting, and wonder if perhaps coupled with
> > > Diamond or a similar object system, Euphoria could in fact have some of
> > > the extra benefits of Lisp.
> > >
> > 
> > I'd need to study more Lisp to see if I could implement all of what you 
> > are
> > discussing. I'm confident that I could provide function objects as part 
> > of
> > the Diamond Standard Class Library or as part of the Diamond kernel. I 
> > will
> > look into this possiblity after I complete the 4.0 release.
> > 
> 
> Well, you can pass around functions as first-order objects in Euphoria 
> using routine-id.  It is kind of clumsy and not nearly as elegant as in 
> a real functional language like Haskell, but it can be done.
> 
> I've implemented genetic programming in Euphoria (usually done in LISP) 
> where arbitrary functions are strung together.  You have to write a 
> routine-id based evaluator to process the resulting expressions, but it 
> works fine...
> 

That is only one aspect of first-class objects. You still won't be able to
create new routines at runtime and have them execute in the same address space as
the application (eg. have them share variables). With using routine-id, you can
only deal with routines that already exist at runtime. There is a convoluted
method of doing this in WIndows/Linux environments, but it involves compiling a
new routine as a shared library (eg. a Windows DLL) at runtime then loading that
library, then running the routine - not a pretty method at all.

-- 
Derek