Mailing List Archive

Fernando Mato Mira <matomira@iname.com> writes:

> I seem to have forgotten C, too..

you lucky bastard!

--
J o h a n K u l l s t a m
[kullstam@ne.mediaone.net]
Don't Fear the Penguin!

On 16 Jun 1999 00:46:56 +0300, Harvey J. Stein wrote:
>wtanksle@dolphin.openprojects.net (William Tanksley) writes:

> > On Tue, 15 Jun 1999 01:54:53 GMT, Maxwell Sayles wrote:
> > >Robin Becker wrote:

> > >> postfix, prefix, infix etc etc are isosemantic

> > >for myself and the others who might not know... can we get an example of
> > >each?
> > >and i remember someone mentioned parenthesized vs non-parenthesized...

> > Prefix (C, Lisp, Scheme):

> > function(that(x(1)))
> > or:
> > (do-this (do-that (x 1)))
> > (Parenthesis are not optional)

> > Postfix (Forth, Postscript):

> > 3 4 + SWAP MOD do-that
> > rinse on agitate 10 seconds rinse off
> > (Parenthesis are not optional)

> > As a common thread, note that in none of the languages are parenthesis
> > optional. In Postfix parenthesis are not optional because they have nno
> > meaning; in the other languages they're assigned arbitrary meaning.

>This isn't a completely fair example. Postfix can get away without
>parentheses only when a) everything that's not a number is a function
>and b) the arity (# of arguments) of each function is known and fixed.

Not true -- in Forth part (a) holds, but part (b) doesn't. The number of
arguments and number of returns can vary arbitrarily; they're put onto and
taken off of a stack.

And I don't see the relevance of restriction (a). It seems that with or
without it we would get the same result -- postfix doesn't need
parenthesis.

Oh, for example, Forth "immediate" words. These aren't the same as other
functions, since they execute at compile time (in all other respects they
are functions, though).

Also, HP RPN uses syntactic elements which are neither numbers nor
functions.

So therefore, neither of your conditions are necessary.

>Given such restrictions one can also drop the parentheses in prefix
>notation.

You're right here, though.

>Infix still requires parentheses even given the above restrictions.

Yes.

We see that postfix never requires parenthesis, and prefix can skip its
parenthesis under certain conditions. Are there any conditions under
which infix can ignore parenthesis?

>Harvey J. Stein

--
-William "Billy" Tanksley
Utinam logica falsa tuam philosophiam totam suffodiant!
:-: May faulty logic undermine your entire philosophy!

* Klaus Schilling
|
| Steele just rediscovered Scheme.

What, do you mean recently?

--Lars M.

Lars Marius Garshol <larsga@ifi.uio.no> writes:

> * Klaus Schilling
> |
> | Steele just rediscovered Scheme.
>
> What, do you mean recently?

No, in the sense `Steele merely rediscovered scheme, not bring it
into being'

Klaus Schilling

* Klaus Schilling
|
| No, in the sense `Steele merely rediscovered scheme, not bring it
| into being'

I don't understand what you mean by this. The two people who created
Scheme originally were Sussman and Steele. If that isn't bringing it
into being I don't know what would be.

(See section 2.8 of 'The Evolution of Lisp'.
<URL: http://www.stat.ucla.edu/develop/lisp/common/docs/Evolution-of-Lisp.ps.gz>)

--Lars M.

Lars Marius Garshol <larsga@ifi.uio.no> writes:

> * Klaus Schilling
> |
> | No, in the sense `Steele merely rediscovered scheme, not bring it
> | into being'
>
> I don't understand what you mean by this. The two people who created
> Scheme originally were Sussman and Steele. If that isn't bringing it
> into being I don't know what would be.

No, they discovered Scheme, they did not create it.

Klaus Schilling

On 16 Jun 1999, Klaus Schilling wrote:

> Lars Marius Garshol <larsga@ifi.uio.no> writes:
>
> > * Klaus Schilling
> > |
> > | No, in the sense `Steele merely rediscovered scheme, not bring it
> > | into being'
> >
> > I don't understand what you mean by this. The two people who created
> > Scheme originally were Sussman and Steele. If that isn't bringing it
> > into being I don't know what would be.
>
> No, they discovered Scheme, they did not create it.
>
> Klaus Schilling
>

*If* you're trying to be enigmatic, PLEASE STOP IT!
-- you're only managing to be obscure.

( If, on the other hand, you're trying to be ignorant, then
by all means, go right ahead! That, we can handle! ;-)


---| Steven D. Majewski (804-982-0831) <sdm7g@Virginia.EDU> |---
---| Department of Molecular Physiology and Biological Physics |---
---| University of Virginia Health Sciences Center |---
---| P.O. Box 10011 Charlottesville, VA 22906-0011 |---

"IA-64 looks just about like what you would expect from a PA-RISC
and IA-32 train wreck with a little VLIW thrown in for spice."
* Thomas J. Merritt <tjm@spam.codegen.com> in <news:comp.arch> *

>>>>> "Klaus" == Klaus Schilling <Klaus.Schilling@home.ivm.de> writes:

Klaus> Lars Marius Garshol <larsga@ifi.uio.no> writes:
>> * Klaus Schilling | | No, in the sense `Steele merely
>> rediscovered scheme, not bring it | into being'
>>
>> I don't understand what you mean by this. The two people who
>> created Scheme originally were Sussman and Steele. If that isn't
>> bringing it into being I don't know what would be.

Klaus> No, they discovered Scheme, they did not create it.

In the interests of ending this, I think I can explain what Klaus means
here.

There's a philosophical debate about whether especially mathematical
ideas are `created' or `discovered'; that is, whether they were cobbled
together by a human or lay there secretly for years only to be stumbled
across by the same human. Mathematicians typically believe that they
only discovered mathematical theorems etc., rather than create them;
it's a sort of tribute to the spare elegance of group theory, for
example.

Klaus appears to mean that Scheme is so mind bogglingly elegant that
Steele could not have created it out of whole cloth, merely discovered
it as a mathematical truth.

As an aside I really don't think Scheme is anywhere near *that* elegant,
and as a matter of fact it hurts me to use the language for more than
trivial things, *precisely* because the damn thing is so small. Fer
crissakes, you don't even have the ability to create an aggregate type
in R5RS! You can fake it; but it sucks, and it doesn't integrate well
with the built in type system...

ObPython: Python is far easier to use IMHO, because it has more stuff
available. I don't need to reinvent the hash table, or cobble together
OOP with closures, 'cause it's done for me, and I don't need to reinvent
SMTP, FTP, network sockets, any of that because it's all in the standard
libraries. When it isn't, like XML, it's usually available elsewhere,
or failing everything I can hack one together myself and drop it in.
Large languages permit small programs, or something like that.
--
Graham Hughes <graham@ccs.ucsb.edu>
GPG Fingerprint: 4FC5 80F0 63EB 00BE F438 E365 084B 4010 60BF 17D3
((lambda (x) (list x (list 'quote x)))
'(lambda (x) (list x (list 'quote x))))

Graham Hughes wrote:

> trivial things, *precisely* because the damn thing is so small. Fer
> crissakes, you don't even have the ability to create an aggregate type
> in R5RS! You can fake it; but it sucks, and it doesn't integrate well
> with the built in type system...

I have a somewhat similar opinion. I can understand the open philosophy of
the standard, but the real problem is that almost every implementation goes
with their favorite OO way (maybe sometimes because of a lack of a CLOS
exposure. I didn't know about CLOS until I started to do CL, and many
schemers are plainly _disgusted_ about CL [Disclaimer: my students called me
"the Schemeboy" [oops, IYKWIM ;-)] back at UBA] ).
Anyway, I find it strange that tinyclos is not more popular as a ready-to-go
and optimized object system.

So then, you're faced with the choice of STk `beign right', MzScheme having
the best plan (IDE, static debugger (what about the dynamic debugger now?)
but no compilation (is it there yet?).
Of course I wouldn't choose STk just because it has a nativized tinyclos. I
could have used the tinyclos
source as it was, but I just went and integrated it into the whole type
hierarchy of MzScheme (adding metaclasses for the original MzScheme object
system (not for me, to give away), nativized primitives.
Unfortunately, that stuff didn't get merged into the distribution, as it
adds to support burden (and probably it's not interesting for them), and
they have dev plans to get some better implementation.

I even went and added a lot of CL stuff on top of that implementation
(source code from CMUCL).
It's possible to move around. This is very important when at some point you
get stuck (thread-unsafe implementation, inefficiency, requirement to run on
JVM, whatever).
I now use a portable way of writing Lisp, at least until CLers and Schemers
decide what can we do about
#f and nil (err.. did I say `comet' before?)