A critic of Guido's blog on Python's lambda

[Xah Lee]

Python, Lambda, and Guido van Rossum

Xah Lee, 2006-05-05

In this post, i'd like to deconstruct one of Guido's recent blog about
lambda in Python.

In Guido's blog written in 2006-02-10 at
http://www.artima.com/weblogs/viewpo...?thread=147358

is first of all, the title “Language Design Is Not Just Solving
Puzzles�. In the outset, and in between the lines, we are told that
“I'm the supreme intellect, and I created Python�.

This seems impressive, except that the tech geekers due to their
ignorance of sociology as well as lack of analytic abilities of the
mathematician, do not know that creating a language is a act that
requires little qualifications. However, creating a language that is
used by a lot people takes considerable skill, and a big part of that
skill is salesmanship. Guido seems to have done it well and seems to
continue selling it well, where, he can put up a title of belittlement
and get away with it too.

Gaudy title aside, let's look at the content of his say. If you peruse
the 700 words, you'll find that it amounts to that Guido does not like
the suggested lambda fix due to its multi-line nature, and says that he
don't think there could possibly be any proposal he'll like. The
reason? Not much! Zen is bantered about, mathematician's impractical
ways is waved, undefinable qualities are given, human's right brain is
mentioned for support (neuroscience!) , Rube Goldberg contrivance
phraseology is thrown, and coolness of Google Inc is reminded for the
tech geekers (in juxtaposition of a big notice that Guido works
there.).

If you are serious, doesn't this writing sounds bigger than its
content? Look at the gorgeous ending: “This is also the reason why
Python will never have continuations, and even why I'm uninterested in
optimizing tail recursion. But that's for another installment.� . This
benevolent geeker is gonna give us another INSTALLMENT!

There is a computer language leader by the name of Larry Wall, who said
that “The three chief virtues of a programmer are: Laziness,
Impatience and Hubris� among quite a lot of other ingenious
outpourings. It seems to me, the more i learn about Python and its
leader, the more similarities i see.

So Guido, i understand that selling oneself is a inherent and necessary
part of being a human animal. But i think the lesser beings should be
educated enough to know that fact. So that when minions follow a
leader, they have a clear understanding of why and what.

----

Regarding the lambda in Python situation... conceivably you are right
that Python lambda is perhaps at best left as it is crippled, or even
eliminated. However, this is what i want: I want Python literatures,
and also in Wikipedia, to cease and desist stating that Python supports
functional programing. (this is not necessarily a bad publicity) And, I
want the Perl literatures to cease and desist saying they support OOP.
But that's for another installment.

----
This post is archived at:
http://xahlee.org/UnixResource_dir/w...bda_guido.html

Â* Â* Xah
Â* Â* xa*@xahlee.org
∑ http://xahlee.org/

[Rhino]

"I V" <wr******@gmail .com> wrote in message
news:pa******** *************** ****@gmail.com. ..

On Fri, 05 May 2006 17:26:26 -0700, Xah Lee wrote:

Regarding the lambda in Python situation... conceivably you are right
that Python lambda is perhaps at best left as it is crippled, or even
eliminated. However, this is what i want: I want Python literatures,
and also in Wikipedia, to cease and desist stating that Python supports
functional programing. (this is not necessarily a bad publicity) And, I

What does lambda have to do with supporting or not supporting functional
programming?

What does any of this have to do with Java?

--
Rhino

[Ken Tilton]

Steve R. Hastings wrote:

On Fri, 05 May 2006 21:16:50 -0400, Ken Tilton wrote:

The upshot of
what he wrote is that it would be really hard to make semantically
meaningful indentation work with lambda.

Pretty much correct. The complete thought was that it would be painful
all out of proportion to the benefit.

See, you don't need multi-line lambda, because you can do this:
def make_adder(x):
def adder_func(y):
sum = x + y
return sum
return adder_func

add5 = make_adder(5)
add7 = make_adder(7)

print add5(1) # prints 6
print add5(10) # prints 15
print add7(1) # prints 8
Note that make_adder() doesn't use lambda, and yet it makes a custom
function with more than one line. Indented, even.

You could also do this:
lst = [] # create empty list
def f(x):
return x + 5
lst.append(f)
del(f) # now that the function ref is in the list, clean up temp name

print lst[0](1) # prints 6
Is this as convenient as the lambda case?

lst.append(lamb da x: x + 7)
print lst[1](1) # prints 8
No; lambda is a bit more convenient. But this doesn't seem like a very
big issue worth a flame war.

<g> Hopefully it can be a big issue and still not justify a flame war.

Mileages will always vary, but one reason for lambda is precisely not to
have to stop, go make a new function for this one very specific use,
come back and use it as the one lambda statement, or in C have an
address to pass. but, hey, what are editors for? :)

the bigger issue is the ability of a lambda to close over arbitrary
lexically visible variables. this is something the separate function
cannot see, so one has to have a function parameter for everything.

but is such lexical scoping even on the table when Ptyhon's lambda comes
up for periodic review?
If GvR says multi-line lambda would make
the lexer more complicated and he doesn't think it's worth all the effort,
I don't see any need to argue about it.

Oh, no, this is just front porch rocking chair BS. But as an enthuiastic
developer I am sensitive to how design choices express themselves in
ways unanticipated. Did the neat idea of indentation-sensitivity doom
pythonistas to a life without the sour grapes of lambda?

If so, Xah's critique missed that issue and was unfair to GvR in
ascribing his resistance to multi-statement lamda to mere BDFLism.

kenny

--
Cells: http://common-lisp.net/project/cells/

"Have you ever been in a relationship?"
Attorney for Mary Winkler, confessed killer of her
minister husband, when asked if the couple had
marital problems.

[John Bokma]

Reported for excessive crossposting.

--
John Bokma Freelance software developer
&
Experienced Perl programmer: http://castleamber.com/

[John Bokma]

"Rhino" <no************ ***********@nos pam.com> wrote:

What does any of this have to do with Java?

Xah Lee is well known for abusing Usenet for quite some time, report
his posts as excessive crossposts to:

abuse at bcglobal dot net
abuse at dreamhost dot com

IIRC this is his third ISP account in 2 weeks, so it *does* work.

Moreover, his current hosting provider, dreamhost, might drop him soon.

--
John Bokma Freelance software developer
&
Experienced Perl programmer: http://castleamber.com/

[Glyn Millington]

Ken Tilton <ke*******@gmai l.com> writes:

kenny (wondering what to call a flock (?!) of lemmings)

Couldn't find it here:-

http://ojohaven.com/collectives/

So I would propose a "leap" of lemmings :-)
WAY OT! Sorry.

atb



Glyn

[Alex Martelli]

Ken Tilton <ke*******@gmai l.com> wrote:
...

Absolutely. That's why firms who are interested in building *seriously*
large scale systems, like my employer (and supplier of your free mail ... Obviously will not scale. Never.

Well... hardly ever!
You are talking about being incredibly popular. I was talking about

Who, me? I'm talking about the deliberate, eyes-wide-open choice by
*ONE* firm -- one which happens to more or less *redefine* what "large
scale" computation *means*, along many axes. That's got nothing to do
with Python being "incredibly popular": it has everything to do with
scalability -- the choice was made in the late '90s (and, incidentally,
by people quite familiar with lisp... no less than the reddit.com guys,
you know, the ones who recently chose to rewrite their side from Lisp to
Python...?), based on scalability issues, definitely not "popularity "
(Python in the late '90s was a very obscure, little-known language).
kenny (who is old enough to have seen many a language come and go)

See your "many a language" and raise you one penny -- besides sundry
Basic dialects, machine languages, and microcode[s], I started out with
Fortran IV and APL, and I have professionally programmed in Pascal (many
dialects), Rexx, Forth, PL/I, Cobol, Lisp before there was a "Common"
one, Prolog, Scheme, Icon, Tcl, Awk, EDL, and several proprietary 3rd
and 4th generation languages -- as well of course as C and its
descendants such as C++ and Java, and Perl. Many other languages I've
studied and played with, I've never programmed _professionally _ (i.e.,
been paid for programs in those languages), but I've written enough
"toy" programs to get some feeling for (Ruby, SML, O'CAML, Haskell,
Snobol, FP/1, Applescript, C#, Javascript, Erlang, Mozart, ...).

Out of all languages I know, I've deliberately chosen to specialize in
Python, *because it scales better* (yes, functional programming is
_conceptually_ perfect, but one can never find sufficiently large teams
of people with the right highly-abstract mathematical mindset and at the
same time with sufficiently down-to-earth pragmaticity -- so, for _real
world_ uses, Python scales better). When I was unable to convince top
management, at the firm at which I was the top programmer, that the firm
should move to Python (beyond the pilot projects which I led and gave
such stellar results), I quit, and for years I made a great living as a
freelance consultant (mostly in Python -- once in a while, a touch of
Pyrex, C or C++ as a vigorish;-).

That's how come I ended up working at the firm supplying your free mail
(as Uber Tech Lead) -- they reached across an ocean to lure me to move
from my native Italy to California, and my proven excellence in Python
was their prime motive. The terms of their offer were just too
incredible to pass by... so, I rapidly got my O1 visa ("alien of
exceptional skills"), and here I am, happily ubertechleading ... and
enjoying Python and its incredibly good scalability every single day!
Alex

[Alex Martelli]

Steve R. Hastings <st***@hastings .org> wrote:
...

But the key in the whole thread is simply that indentation will not
scale. Nor will Python.
This is a curious statement, given that Python is famous for scaling well.

I think "ridiculous " is a better characterizatio n than "curious", even
if you're seriously into understatement.

I won't say more, since Alex Martelli already pointed out that Google is
doing big things with Python and it seems to scale well for them.

And of course we're not the only ones. In fact, I believe that we're
not even among the firms which have reported their experiences in the
official "Python Success Stories" -- IBM, Industrial Light and Magic,
NASA, etc, etc, are there, but we arent. I guess we just prefer to play
our cards closer to our chest -- after all, if our competitors choose to
use inferior languages, it's hardly to our advantage to change that;-).
Alex

[Kay Schluehr]

Ken Tilton wrote:

Oh, my, you are preaching to the herd (?!) of lemmings?! Please tell me
you are aware that lemmings do not have ears. You should just do Lisp
all day and add to the open source libraries to speed Lisp's ascendance.
The lemmings will be liberated the day Wired puts John McCarthy on the
cover, and not a day sooner anyway.

And then the 12th vanished Lisper returns and Lispers are not
suppressed anymore and won't be loosers forever. The world will be
united in the name of Lisp and Lispers will be leaders and honorables.
People stop worrying about Lispers as psychpaths and do not consider
them as zealots, equipped with the character of suicide bombers. No,
Lisp means peace and paradise.

[Bill Atkins]

"Kay Schluehr" <ka**********@g mx.net> writes:

And then the 12th vanished Lisper returns and Lispers are not
suppressed anymore and won't be loosers forever. The world will be
The mark of a true loser is the inability to spell 'loser.' Zing!
them as zealots, equipped with the character of suicide bombers. No,

A very reasonable comparison. Yes, the more I think about it, we Lisp
programmers are a lot like suicide bombers.

Doofus.

--
This is a song that took me ten years to live and two years to write.
- Bob Dylan

[Thomas F. Burdick]

Ken Tilton <ke*******@gmai l.com> writes:

<g> Hopefully it can be a big issue and still not justify a flame war.

Mileages will always vary, but one reason for lambda is precisely not
to have to stop, go make a new function for this one very specific
use, come back and use it as the one lambda statement, or in C have an
address to pass. but, hey, what are editors for? :)

the bigger issue is the ability of a lambda to close over arbitrary
lexically visible variables. this is something the separate function
cannot see, so one has to have a function parameter for everything.

but is such lexical scoping even on the table when Ptyhon's lambda
comes up for periodic review?

This is second-hand, as I don't actually follow Python closely, but
from what I've heard, they now have reasonable scoping rules (or maybe
they're about to, I'm not sure). And you can use def as a
Scheme-style inner define, so it's essentially a LABELS that gets the
indentation wrong. This means they have proper closures, just not
anonymous ones. And an egregiously misnamed lambda that should be
fixed or thrown out.

If Python gets proper macros it won't matter one bit that they only
have named closures, since you can macro that away in a blink of an
eye.