Shriram Krishnamurthi has just announced the following elsewhere; it might
be of interest to c.l.s, c.l.f, and c.l.p: http://list.cs.brown.edu/pipermail/p...il/008382.html
The Fate Of LAMBDA in PLT Scheme v300
or
Lambda the Ultimate Design Flaw
About 30 years ago, Scheme had FILTER and MAP courtesy of Lisp hackers
who missed them from their past experience. To this collection,
Scheme added a lexically-scoped, properly-functioning LAMBDA. But,
despite of the PR value of anything with Guy Steele's name associated
with it, we think these features should be cut from PLT Scheme v300.
We think dropping FILTER and MAP is pretty uncontroversial ; (filter P
S) is almost always written clearer as a DO loop (plus the LAMBDA is
slower than the loop). Even more so for (map F S). In all cases,
writing the equivalent imperative program is clearly beneficial.
Why drop LAMBDA? Most Scheme users are unfamiliar with Alonzo Church
(indeed, they don't even know that he was related to Guy Steele), so
the name is confusing; also, there is a widespread misunderstandin g
that LAMBDA can do things that a nested function can't -- we still
recall Dan Friedman's Aha! after we showed him that there was no
difference! (However, he appears to have since lapsed in his ways.)
Even with a better name, we think having the two choices side-by-side
just requires programmers to think about their program; not having the
choice streamlines the thought process, and Scheme is designed from
the ground up to, as much as possible, keep programmers from thinking
at all.
So now FOLD. This is actually the one we've always hated most,
because, apart from a few examples involving + or *, almost every time
we see a FOLD call with a non-trivial function argument, we have to
grab pen and paper and imagine the *result* of a function flowing back
in as the *argument* to a function. Plus, there are *more* arguments
coming in on the side! This is all absurdly complicated. Because
almost all the examples of FOLD we found in practice could be written
as a simple loop with an accumulator, this style should be preferred,
perhaps with us providing a simple helper function to abstract away
the boilerplate code. At any rate, FOLD must fold.
--The PLT Scheme Team
Jul 18 '05
47  2746 
alex goldman wrote: Daniel Silva wrote:
At any rate, FOLD must fold.
I personally think GOTO was unduly criticized by Dijkstra. With the benefit
of hindsight, we can see that giving up GOTO in favor of other primitives
failed to solve the decades-old software crisis.
The fault of goto in imperative languages is that it has no
arguments, thus creating spaghetti of gotos and assignments.
Continuations rule!
In article <ma************ *************** ***********@pyt hon.org>,
=?iso-8859-1?Q?Fran=E7ois? = Pinard <pi****@iro.umo ntreal.ca> wrote: [Sunnan]
[...] for Pythons ideal of having one canonical, explicit way to
program.
No doubt it once was true, but I guess this ideal has been abandoned a
few years ago.
My honest feeling is that it would be a mis-representation of Python,
assertng today that this is still one of the Python's ideals.
Mind providing evidence rather than simply citing your feelings? Yes,
there's certainly redundancy in Python right now, but a large portion of
that will go away in Python 3.0. So where's the abandonment of the
ideal?
--
Aahz (aa**@pythoncra ft.com) <*> http://www.pythoncraft.com/
"The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code --
not in reams of trivial code that bores the reader to death." --GvR
Daniel Silva <ds****@ccs.neu .edu> writes:
[...] So now FOLD. This is actually the one we've always hated most,
because, apart from a few examples involving + or *, almost every time
we see a FOLD call with a non-trivial function argument, we have to
grab pen and paper and imagine the *result* of a function flowing back
in as the *argument* to a function. Plus, there are *more* arguments
coming in on the side! This is all absurdly complicated. Because
almost all the examples of FOLD we found in practice could be written
as a simple loop with an accumulator, this style should be preferred,
perhaps with us providing a simple helper function to abstract away
the boilerplate code. At any rate, FOLD must fold.
Couldn't you leave it in for just another month? And during the
remaining month, we'll just call it the "APRIL FOLD".
--
Tom Breton, the calm-eyed visionary
On 1 Apr 2005 20:00:13 -0500, aa**@pythoncraf t.com (Aahz) wrote: In article <ma************ *************** ***********@pyt hon.org>,
=?iso-8859-1?Q?Fran=E7ois? = Pinard <pi****@iro.umo ntreal.ca> wrote:[Sunnan]
[...] for Pythons ideal of having one canonical, explicit way to
program.
No doubt it once was true, but I guess this ideal has been abandoned a
few years ago.
My honest feeling is that it would be a mis-representation of Python,
assertng today that this is still one of the Python's ideals.
^^^^^--in particular?? That makes for a complex sentence ;-)
Mind providing evidence rather than simply citing your feelings? Yes,
there's certainly redundancy in Python right now, but a large portion of
that will go away in Python 3.0. So where's the abandonment of the
ideal?
--
Aahz (aa**@pythoncra ft.com) <*> http://www.pythoncraft.com/
"The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code --
not in reams of trivial code that bores the reader to death." --GvR
Regards,
Bengt Richter
Aahz wrote: "The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code --
not in reams of trivial code that bores the reader to death." --GvR
Can anyone please point me to the text that quote was taken from? I
tried to use a search engine but I only found quotations, not the source.
Sunnan
[Aahz] "The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code --
not in reams of trivial code that bores the reader to death." --GvR
[Sunnan] Can anyone please point me to the text that quote was taken from? I
tried to use a search engine but I only found quotations, not the source.
That's because it was originally in email to a company-internal
mailing list. If you're willing to move to Fredericksburg, VA and
work for Zope Corp, perhaps they'll let you in to the PythonLabs list
archives. Fair warning: I work for Zope Corp, and I'm not sure I can
get into those archives. So don't switch jobs _just_ for that.
[Aahz] =?iso-8859-1?Q?Fran=E7ois? = Pinard <pi****@iro.umo ntreal.ca> wrote:
No doubt it once was true, but I guess this ideal has been
abandoned a few years ago. My honest feeling is that it would be a
mis-representation of Python, assertng today that this is still one
of the Python's ideals.
Mind providing evidence rather than simply citing your feelings?
The important word was "honest", not "feeling". :-)
Yes, there's certainly redundancy in Python right now, [...]
See here, I'm not asking you for proofs. :-)
but a large portion of that will go away in Python 3.0.
And when will that be? The principle of "there is only way to do it"
was observable in Python 1.5.2, and started to disappear at that time.
How many years between 1.5.2 and 3.0?
So where's the abandonment of the ideal?
Many of us are using Python today, week after week, year long. So let's
be pragmatic. Python is what it became and now is. Let's not define it
as a memory from the past nor as a futuristic dream.
--
François Pinard http://pinard.progiciels-bpi.ca
Aahz wrote: In article <ma************ *************** ***********@pyt hon.org>,
=?iso-8859-1?Q?Fran=E7ois? = Pinard <pi****@iro.umo ntreal.ca> wrote:
[Sunnan]
[...] for Pythons ideal of having one canonical, explicit way to
program.
No doubt it once was true, but I guess this ideal has been abandoned a
few years ago.
My honest feeling is that it would be a mis-representation of Python,
assertng today that this is still one of the Python's ideals.
Mind providing evidence rather than simply citing your feelings? Yes,
there's certainly redundancy in Python right now, but a large portion of
that will go away in Python 3.0. So where's the abandonment of the
ideal?
Mind providing evidence rather than citing your opinions? I don't see
any evidence that Python 3.0 will adopt Turing-machine-like canonical
algorithms, and anything more complex is (at least from a theoretical
point of view) merely syntactic sugar.
regards
Steve
--
Steve Holden +1 703 861 4237 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
Python Web Programming http://pydish.holdenweb.com/
alex goldman wrote: Daniel Silva wrote:
At any rate, FOLD must fold.
I personally think GOTO was unduly criticized by Dijkstra. With the benefit
of hindsight, we can see that giving up GOTO in favor of other primitives
failed to solve the decades-old software crisis.
What software crisis? Knuth (among others) has demonstrated that it's
possible to do structured programming in assembly language (though I
have to say that not all his MIX was particularly well-structured).
The danger in GOTO is that it allows the undisciplined programmer to
develop a badly-structured solution to a programming problem. A
disciplined programmer will write well-structured code with whatever
tools come to hand.
regards
Steve
--
Steve Holden +1 703 861 4237 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
Python Web Programming http://pydish.holdenweb.com/
Tim Peters wrote: [Aahz]
"The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code --
not in reams of trivial code that bores the reader to death." --GvR
[Sunnan]
Can anyone please point me to the text that quote was taken from? I
tried to use a search engine but I only found quotations, not the source.
That's because it was originally in email to a company-internal
mailing list. If you're willing to move to Fredericksburg, VA and
work for Zope Corp, perhaps they'll let you in to the PythonLabs list
archives. Fair warning: I work for Zope Corp, and I'm not sure I can
get into those archives. So don't switch jobs _just_ for that.
It's just that I'm having a hard time matching that quote to what I
though python was about. I thought boring code was considered a virtue
in python. ("Explicit is better than implicit", "sparse is better than
dense".)
Because what is "boring"? The opposite of dense, tense, intense. Utterly
predictable; it's like the combination of all my prejudices. Even before
I knew, I thought "Bet Python separates statements from expressions".
Sunnan
PS.
(People easily offended can substitute "boring" for "readable" in the
above text.) This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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