Programming challenge: wildcard exclusion in cartesian products

[Alexander Schmolck]

Mark Carter <me at privacy.net> writes:
> A programmers mindset is usually geared towards "writing applications". What
> I'm currently doing in Lisp is building up functions as I need them. Using
> emacs, I can just C-x C-e to make my functions "live", and when it's time to
> stop for the day, save my working image so that I can use it the next day.
> 
> 
> It seems to me that only Forth or Scheme really matches this capability. 

Not really. I'd say matlab's and squeak's (and presumably most smalltalks')
interactive environment is quite superior to cl+slime. Emacs lisp is also
better and I'd also suspect erlang to be better in some ways, but I haven't
used it yet. APL and descendants (J and K) also tend to have quite reasonable
interactive facilities and so do CAS systems.

> Ruby and Python come kinda close - they do have a REPL, but it's kinda
> clunky to try to create functions on the fly, plus of course they don't
> support the idea of an image.

I don't think interactively creating functions is much harder in python but
changing module and class definitions is.

Actually although cl+slime is rather nice it is inferior to the much less
sophisticated and capable ipython+emacs combo in some regards (runtime error
reporting in CL tends to be pretty crap; (i)python docstrings, ease of
interactive testing and shell integration are superior). It's also much
easier to serialize stuff in python than it is in common lisp (never mind
pickle; you can't even readably print hashtables -- and unless I'm missing
something this is not user-fixable which really sucks).

Of course it's *much* easier to supply a nice interactive experience for a
quite limited language such as matlab than it is for CL (mostly because CL is
more powerful and geared towards efficient code generation).

So CL might well have the best interactiveness/(expressiveness*speed) ratio.

'as