Python syntax in Lisp and Scheme

[Kenny Tilton]

Re: Python syntax in Lisp and Scheme



Toni Nikkanen wrote:
[color=blue]
> kalath@lycos.co m (Mark Brady) writes:
>
>[color=green]
>>just me, I prefer S-exps and there seems to be a rebirth in the Scheme
>>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.[/color]
>
>
> It's be interesting to know where people got the idea of learning
> Scheme/LISP from (apart from compulsory university courses)?[/color]

<g> We wonder alike. That's why I started:

http://alu.cliki.net/The%20Road%20to%20Lisp%20Survey

That recently got repotted from another cliki and it's a little mangled,
but until after ILC2003 I am a little too swamped to clean it up. But
there is still a lot of good stuff in there. On this page I grouped
folks according to different routes to Lisp (in the broadest sense of
that term): http://alu.cliki.net/The%20RtLS%20by%20Road

You will find some old-timers because I made the survey super-inclusive,
but my real interest was the same as yours: where are the New Lispniks
coming from?

Speaking of which, Mark Brady cited Python as a stepping-stone, and I
have been thinking that might happen, but the survey has yet to confirm.
Here's one: http://alu.cliki.net/Robbie%20Sedgew ick's%20Road%20 to%20Lisp

So Ping! Mark Brady, please hie ye (and all the others who followed the
same road to Lisp) to the survey and correct the record.

I think[color=blue]
> that for me, it was the LPC language used in LPmuds. It had a
> frightening feature called lambda closures, and useful functions such
> as map and filter. Then one day I just decided to bite the bullet and
> find out where the heck all that stuff came from (my background was
> strongly in C-like languages at that point. LPC is like C with some
> object-oriented and some FP features.)
>
> Yes, I know, there's nothing frightening in lambda closures. But the
> way they were implemented in LPC (actually just the syntax) was
> terrible :)[/color]

You could cut and paste that into the survey as well. :)

kenny

[Terry Reedy]

Re: Python syntax in Lisp and Scheme


"Mark Brady" <kalath@lycos.c om> wrote in message
news:e840346c.0 310030302.6be0c 378@posting.goo gle.com...[color=blue]
> This whole thread is a bad idea.[/color]

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.
[color=blue]
> If you like python then use python.[/color]

As I plan to do.
[color=blue]
> 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[/color]
cheme[color=blue]
> 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.[/color]

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

[Toni Nikkanen]

Re: Python syntax in Lisp and Scheme

Kenny Tilton <ktilton@nyc.rr .com> writes:
[color=blue]
> Speaking of which, Mark Brady cited Python as a stepping-stone, and I
> have been thinking that might happen, but the survey has yet to
> confirm.[/color]

It usually happens that when I google for some scheme/lisp-isms,
I get lots of Python mailing list messages as results. There's
something going on with that.

[Kenny Tilton]

Re: Python syntax in Lisp and Scheme



Kenny Tilton wrote:
[color=blue]
>
>
> Toni Nikkanen wrote:
>[color=green]
>> It's be interesting to know where people got the idea of learning
>> Scheme/LISP from (apart from compulsory university courses)?[/color]
>
>
> <g> We wonder alike. That's why I started:
>
> http://alu.cliki.net/The%20Road%20to%20Lisp%20Survey
>
> That recently got repotted from another cliki and it's a little mangled,
> but until after ILC2003 I am a little too swamped to clean it up.[/color]

Me and my big mouth. Now that I have adevrtised the survey far and wide,
and revisited it and seen up close the storm damage, sh*t, there goes
the morning. :) Well, I needed a break from RoboCells:

http://sourceforge.net/projects/robocells/

I am going to do what I can to fix up at least the road categorization,
and a quick glance revealed some great new entries, two that belong in
my Top Ten (with apologies to those getting bumped).

kenny

[Lothar Scholz]

Re: Python syntax in Lisp and Scheme

Paul Rubin <http://phr.cx@NOSPAM.i nvalid> wrote in message news:<7xvfr6lvh 6.fsf@ruckus.br ouhaha.com>...[color=blue]
> mike420@ziplip. com writes:[color=green]
> > If the answer is yes, would many Python programmers switch to Lisp
> > or Scheme if they were offered identation-based syntax?[/color]
>
> I don't think the syntax is that big a deal. But programming in lisp
> or scheme has a creaky feeling these days, because the traditional
> runtime libraries in those languages have fallen so far behind the
> times.[/color]

Funny. Yesterday i downloaded the trial version of Franz Lisp (Allegro
CL).
I can'T say if the runtime libraries are out of date because there is
absolute no documentation for the runtime libraries - of course they
also bundle the ANSI-Common Lisp book.

I found that they still want to sell every fucking line of code in an
extra library raising the price to an unexceptable high value.

[Jeremy H. Brown]

Re: Python syntax in Lisp and Scheme

"Terry Reedy" <tjreedy@udel.e du> writes:[color=blue]
> 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)?[/color]

According to the "Revised(5) Report on the Algorithmic Language
Scheme", "Scheme is a statically scoped and properly tail-recursive
dialect of the Lisp programming language..." It's certainly not a
dialect of Common Lisp, although it is one of CL's ancestors.

I'm sure if you do some web-groveling, you can find some substantial
comparisons of the two; I personally think they have more in common
than not. Here are a few of the (arguably) notable differences:

Scheme Common Lisp
Philosophy minimalism comprehensivene ss
Namespaces one two (functions, variables)
Continuations yes no
Object system no yes
Exceptions no yes
Macro system syntax-rules defmacro
Implementations >10 ~4
Performance "worse" "better"
Standards IEEE ANSI
Reference name R5RS CLTL2
Reference length 50pp 1029pp
Standard libraries "few" "more"
Support Community Academic Applications writers

The Scheme community has the SRFI process for developing additional
almost-standards. I don't know if the CL community has something
equivalent; I don't think they did a year ago.
[color=blue]
> 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?[/color]

Try them both, see which one works for you in what you're doing.

Jeremy

[Paul Rubin]

Re: Python syntax in Lisp and Scheme

Oren Tirosh <oren-py-l@hishome.net> writes:[color=blue]
> Implementing Python-like syntax in LISP or even a full Python
> implementation in LISP would be a worthwhile goal (LPython?). BTW, this
> kind of implementation is one of the relatively few programming tasks
> that can benefit greatly from macros. The Python semantics can be mostly
> done using macros and a preprocessor would translated Python syntax to
> s-expression code that uses those macros.[/color]

If done straightforward ly, the language semantics would end up
different from Python's in a few ways. For example, strings in most
Lisp systems are mutable. Also, Python's class system doesn't map
onto Lisp all that well; Python's variable-scoping rules are bizarre,
and so forth. I think the result would still be worth doing but
it would be a further departure from CPython than, say, Jython is.

[Duane Rettig]

Re: Python syntax in Lisp and Scheme

jhbrown@ai.mit. edu (Jeremy H. Brown) writes:
[color=blue]
> "Terry Reedy" <tjreedy@udel.e du> writes:[color=green]
> > 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)?[/color][/color]

[color=blue]
> I'm sure if you do some web-groveling, you can find some substantial
> comparisons of the two; I personally think they have more in common
> than not. Here are a few of the (arguably) notable differences:[/color]

This is actually a pretty good list. I'm not commenting on
completeness, but I do have a couple of corrections:
[color=blue]
> Scheme Common Lisp
> Philosophy minimalism comprehensivene ss
> Namespaces one two (functions, variables)
> Continuations yes no
> Object system no yes
> Exceptions no yes
> Macro system syntax-rules defmacro
> Implementations >10 ~4[/color]
=============== =============== =============^

See http://alu.cliki.net/Implementation - it lists 9 commercial
implementations , and 7 opensource implementations . There are
probably more.
[color=blue]
> Performance "worse" "better"
> Standards IEEE ANSI
> Reference name R5RS CLTL2[/color]
=============== =============== ==============^

No, CLtL2 is definitely _not_ a reference for ANSI Common Lisp.
It was a snapshot taken in the middle of the ANSI process, and
is out of date in several areas. References which are much closer
to the ANSI spec can be found online at

http://www.franz.com/support/documentation/6.2/ansicl/ansicl.htm

or

http://www.lispworks.com/reference/HyperSpec/Front/index.htm

[color=blue]
> Reference length 50pp 1029pp
> Standard libraries "few" "more"
> Support Community Academic Applications writers
>
> The Scheme community has the SRFI process for developing additional
> almost-standards. I don't know if the CL community has something
> equivalent; I don't think they did a year ago.[/color]

There are many grassroots defacto standards efforts to extend CL in
several areas. Some of these are listed here:

http://alu.cliki.net/Standard

[color=blue][color=green]
> > 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?[/color]
>
> Try them both, see which one works for you in what you're doing.[/color]

Agreed, but of course, I'd recommend CL :-)

--
Duane Rettig duane@franz.com Franz Inc. http://www.franz.com/
555 12th St., Suite 1450 http://www.555citycenter.com/
Oakland, Ca. 94607 Phone: (510) 452-2000; Fax: (510) 452-0182

[Rayiner Hashem]

Re: Python syntax in Lisp and Scheme

> Object system no yes
To be fair, most Scheme implementations come with one, and you can always
download an external one if you want.
[color=blue]
> Macro system syntax-rules defmacro[/color]
Again, depends on the implementation. Gambit offers CL-style macros too.
[color=blue]
> Performance "worse" "better"[/color]
Depends on the implementation. Bigloo did a bit better on the Great Computer
Language Shootout than did CMUCL, though, there were complaints that the
CL-code was sub-par. In the few small benchmarks I've tried on my machine,
Bigloo is pretty competitive with CMUCL.

[Jeremy H. Brown]

Re: Python syntax in Lisp and Scheme

Duane Rettig <duane@franz.co m> writes:[color=blue]
> jhbrown@ai.mit. edu (Jeremy H. Brown) writes:
> This is actually a pretty good list. I'm not commenting on
> completeness, but I do have a couple of corrections:[/color]
....[color=blue][color=green]
> > Implementations >10 ~4[/color]
> =============== =============== =============^
>
> See http://alu.cliki.net/Implementation - it lists 9 commercial
> implementations , and 7 opensource implementations . There are
> probably more.[/color]

Thanks. I hadn't realized the spread was that large.
[color=blue][color=green]
> > Performance "worse" "better"
> > Standards IEEE ANSI
> > Reference name R5RS CLTL2[/color]
> =============== =============== ==============^
>
> No, CLtL2 is definitely _not_ a reference for ANSI Common Lisp.
> It was a snapshot taken in the middle of the ANSI process, and
> is out of date in several areas. References which are much closer
> to the ANSI spec can be found online at
>
> http://www.franz.com/support/documen...icl/ansicl.htm
>
> or
>
> http://www.lispworks.com/reference/H...ront/index.htm[/color]

Thanks again.
[color=blue][color=green]
> >
> > Try them both, see which one works for you in what you're doing.[/color]
>
> Agreed, but of course, I'd recommend CL :-)[/color]

I've arrived at the conclusion that it depends both on your task/goal
and your personal inclinations.

Jeremy

[Marco Antoniotti]

Re: Python syntax in Lisp and Scheme



mike420@ziplip. com wrote:[color=blue]
> I think everyone who used Python will agree that its syntax is
> the best thing going for it. It is very readable and easy
> for everyone to learn. But, Python does not a have very good
> macro capabilities, unfortunately. I'd like to know if it may
> be possible to add a powerful macro system to Python, while
> keeping its amazing syntax, and if it could be possible to
> add Pythonistic syntax to Lisp or Scheme, while keeping all
> of the functionality and convenience. If the answer is yes,
> would many Python programmers switch to Lisp or Scheme if
> they were offered identation-based syntax?[/color]

Why do I feel like crying? :{

Cheers
--
Marco

[Alexander Schmolck]

Re: Python syntax in Lisp and Scheme

prunesquallor@c omcast.net writes:
[color=blue]
> mike420@ziplip. com writes:
>[color=green]
> > I think everyone who used Python will agree that its syntax is
> > the best thing going for it.[/color]
>
> I've used Python. I don't agree.[/color]

I'd be interested to hear your reasons. *If* you take the sharp distinction
that python draws between statements and expressions as a given, then python's
syntax, in particular the choice to use indentation for block structure, seems
to me to be the best choice among what's currently on offer (i.e. I'd claim
that python's syntax is objectively much better than that of the C and Pascal
descendants -- comparisons with smalltalk, prolog or lisp OTOH are an entirely
different matter).

'as

[Kenny Tilton]

Re: Python syntax in Lisp and Scheme



Kenny Tilton wrote:
[color=blue]
>
>
> Kenny Tilton wrote:
>[color=green]
>>
>>
>> Toni Nikkanen wrote:
>>[color=darkred]
>>> It's be interesting to know where people got the idea of learning
>>> Scheme/LISP from (apart from compulsory university courses)?[/color]
>>
>>
>>
>> <g> We wonder alike. That's why I started:
>>
>> http://alu.cliki.net/The%20Road%20to%20Lisp%20Survey
>>
>> That recently got repotted from another cliki and it's a little
>> mangled, but until after ILC2003 I am a little too swamped to clean it
>> up.[/color]
>
>
> Me and my big mouth. Now that I have adevrtised the survey far and wide,
> and revisited it and seen up close the storm damage, sh*t, there goes
> the morning. :)[/color]


OK, I copied over all the twenty-plus pages that got lost in the
repotting, fixed the survey questions, and even took the time to
annotate my Top Ten list:

http://alu.cliki.net/Kenny's%20RtLS% 20Top-Ten

Check it out. The Switch Date pages have been restored, but I do not
think the cross-indexing works until pages get edited and resaved. That
is not the most fascinating breakdown in the world, so it may be a while
before I fuss with that. But this breakdown is cool:

http://alu.cliki.net/The%20RtLS%20by%20Road

More responses always welcome.

kenny

[Terry Reedy]

Re: Python syntax in Lisp and Scheme


"Jeremy H. Brown" <jhbrown@ai.mit .edu> wrote in message
news:uv6brsygx7 8.fsf@tenebrae. ai.mit.edu...[color=blue]
> "Terry Reedy" <tjreedy@udel.e du> writes:[/color]
.....[color=blue][color=green]
> > give a short listing of the current main differences (S vs. CL)?[/color][/color]
....[color=blue]
> than not. Here are a few of the (arguably) notable differences:[/color]
....
Thank you. This is just the sort of preview I wanted.
[color=blue]
> Try them both, see which one works for you in what you're doing.[/color]

My present interest is intellectual broadening. I think I should
start with parts of the current version of SICP and then read a modern
CL chapter on macros.

Terry J. Reedy

[Joe Marshall]

Re: Python syntax in Lisp and Scheme

Alexander Schmolck <a.schmolck@gmx .net> writes:
[color=blue]
> prunesquallor@c omcast.net writes:
>[color=green]
>> mike420@ziplip. com writes:
>>[color=darkred]
>> > I think everyone who used Python will agree that its syntax is
>> > the best thing going for it.[/color]
>>
>> I've used Python. I don't agree.[/color]
>
> I'd be interested to hear your reasons. *If* you take the sharp distinction
> that python draws between statements and expressions as a given, then python's
> syntax, in particular the choice to use indentation for block structure, seems
> to me to be the best choice among what's currently on offer (i.e. I'd claim
> that python's syntax is objectively much better than that of the C and Pascal
> descendants -- comparisons with smalltalk, prolog or lisp OTOH are an entirely
> different matter).[/color]

(I'm ignoring the followup-to because I don't read comp.lang.pytho n)

Indentation-based grouping introduces a context-sensitive element into
the grammar at a very fundamental level. Although conceptually a
block is indented relative to the containing block, the reality of the
situation is that the lines in the file are indented relative to the
left margin. So every line in a block doesn't encode just its depth
relative to the immediately surrounding context, but its absolute
depth relative to the global context. Additionally, each line encodes
this information independently of the other lines that logically
belong with it, and we all know that when some data is encoded in one
place may be wrong, but it is never inconsistent.

There is yet one more problem. The various levels of indentation
encode different things: the first level might indicate that it is
part of a function definition, the second that it is part of a FOR
loop, etc. So on any line, the leading whitespace may indicate all
sorts of context-relevant information. Yet the visual representation
is not only identical between all of these, it cannot even be
displayed.

Is this worse than C, Pascal, etc.? I don't know.
Worse than Lisp, Forth, or Smalltalk? Yes.