Python syntax in Lisp and Scheme

[Mark Brady]

"Terry Reedy" <tjreedy at udel.edu> wrote in message news:<7wednSJ_q_L85uCiXTWJhQ at comcast.com>...
> "Mark Brady" <kalath at lycos.com> wrote in message
> news:e840346c.0310030302.6be0c378 at posting.google.com...
> > This whole thread is a bad idea.
> 
> I could agree that the OP's suggestion is a bad idea but do you
> actually think that discussion and more publicity here for Lisp/Scheme
> is bad?  You make a pretty good pitch below for more Python=>Lisp
> converts.
> 

You are right of course, however I dislike cross posting and I also
dislike blatantly arguing with people over language choice. I would
prefer to lead by example. I think one good program is worth a
thousand words. For example people listen to Paul Graham
(http://www.paulgraham.com/avg.html) when he advocates Common Lisp
because he wrote Viaweb using it and made a fortune thanks to Lisp's
features (details in the link).

> > If you like python then use python.
> 
> As I plan to do.
> 

Nothing wrong with that. Most people on these groups would agree that
Python is a very good choice for a wide range of software projects and
it is getting better with every release.

I think that if you can get over S-exps then Scheme and Common Lisp
feel very like python. I would recommend Pythonistas to at least
experiment with Common Lisp or Scheme even if you are perfectly happy
with Python. After all you have nothing to lose. If you don't like it
then fine you always have Python and you've probably learned something
and if you do like it then you have another language or two under your
belt.
   

> > Personally I find Scheme and Common Lisp easier to read but that's
> > just me, I prefer S-exps and there seems to be a rebirth in the
>  cheme
> > and Common Lisp communities at the moment. Ironically this seems to
> > have been helped by python. I learned python then got interested in
> > it's functional side and ended up learning Scheme and Common Lisp. A
> > lot of new Scheme and Common Lisp developers I talk to followed the
> > same route. Python is a great language and I still use it for some
> > things.
> 
> Other Lispers posting here have gone to pains to state that Scheme is
> not a dialect of Lisp but a separate Lisp-like language.  Could you
> give a short listing of the current main differences (S vs. CL)?  If I
> were to decide to expand my knowledge be exploring the current
> versions of one(I've read the original SICP and LISP books), on what
> basis might I make a choice?
> 
> Terry J. Reedy


This is a difficult question to answer. It's a bit like trying to
explain the differences between Ruby and Python to a Java developer
;-)

*Personally* I find it best to think of Scheme and Common Lisp as two
different but very closely related languages. The actual languages and
communities are quite different.

Common Lisp is a large, very pragmatic, industrial strength language
and its community reflects this. Common Lisp has loads of features
that you would normally only get in add on libraries built right into
the language, it's object
system "CLOS" has to be experienced to be believed and its macro
system is stunning. Some very smart people have already put years of
effort into making it capable of great things such as Nasa's award
winning remote agent software
(http://ic.arc.nasa.gov/projects/remote-agent/).

Scheme is a more functional language and unlike Common Lisp is has a
single namespace for functions and variables (Python is like Scheme in
this regard). Common Lisp can be just as functional but on the whole
the Scheme community seem to embrace functional programming to a
greater extend.

Scheme is like python in that the actual language is quite small and
uses libraries for many of the same tasks Python would use them for,
unlike Common Lisp that has many of these features built into the
language. It also has a great but slightly different macro system
although every implementation I know also has Common Lisp style
Macros.

Scheme doesn't have a standard object system (it's more functional)
but has libraries to provide object systems. This is very hard to
explain to python developers, scheme is kind of like a big python
metaclass engine where different object systems can be used at will.
It's better than I can describe and it is really like a more powerful
version of Pythons metaclass system.

Pythonistas who love functional programming may prefer Scheme to
Common Lisp while Pythonistas who want a standard amazing object
system and loads of built in power in their language may prefer Common
Lisp.

To be honest the these tutorials will do a far better job than I
could:

For Scheme get DrScheme:
http://www.drscheme.org/

and go to

'Teach yourself scheme in fixnum days' : 
http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme.html


For Common Lisp get the trial version of Lispworks:
http://www.lispworks.com/

and go get Mark Watsons free web book:
http://www.markwatson.com/opencontent/lisp_lic.htm

Regards,
Mark.

Ps. If anyone spots a mistake in this mail please correct me, it will
have been an honest one and not an attempt to slander your favourite
language and I will be glad to be corrected, in other words there is
no need to flame me :)