Re: Switch statement (was: Lambda going out of fashion)

On Thu, 23 Dec 2004 19:57:27 GMT, rumours say that rzed <[EMAIL PROTECTED]> might have written: [Why did PEP 275 stall?] >It seems to me that it was regarded as misguidod. QOTPE +1 (PE=Python Era) Oncoming Python book: "Hitchhiker's Guido to the Python Language" -- TZOTZIOY, I speak England v

Re: Reference behavior through C (was: Lambda going out of fashion)

On Wed, 2004-12-29 at 02:08, Cameron Laird wrote: > In article <[EMAIL PROTECTED]>, > Craig Ringer <[EMAIL PROTECTED]> wrote: > . > . > . > > IMO the reference behaviour of functions in the C API could be > >clearer. [snip]

Reference behavior through C (was: Lambda going out of fashion)

In article <[EMAIL PROTECTED]>, Craig Ringer <[EMAIL PROTECTED]> wrote: . . . > IMO the reference behaviour of functions in the C API could be >clearer. One often has to simply know, or refer to the docs, to tell >whether a p

Re: Lambda going out of fashion

In article <[EMAIL PROTECTED]>, Alex Martelli <[EMAIL PROTECTED]> wrote: ><[EMAIL PROTECTED]> wrote: > >> Thanks. :-) Two remarks. >> o One-liner fits the eyes & brains of a portion of people. > >True! So, personally, I'd rather code, e.g., > >def bools(lst): return map(bool, lst) > >rather than b

Re: Improving Python (was: Lambda going out of fashion)

Dima Dorfman wrote: > I happen to not mind the ''.join syntax, but if I did, I would use > > str.join('', seq) > > which is just like a join builtin except that it's not as easy to make > it work on pre-string-method Pythons. just like join, except that it isn't: >>> string.join(seq, sep) u'axb

Re: Improving Python (was: Lambda going out of fashion)

[EMAIL PROTECTED] (Aahz) writes: > While I'm in complete agreement about the "".join() construct on the > basis of looks, I have come to appreciate the fact that I *never* mess up > the order of arguments any more. Yeah. When I needed joinable arrays of strings in Eiffel, I added them to the ARRA

Re: Improving Python (was: Lambda going out of fashion)

On 2004-12-26, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > string methods are nice, but nothing groundbreaking, and their niceness is > almost entirely offset by the horrid "".join(seq) construct that keeps popping > up when people take the "the string module is deprecated" yada yada too > seriously

Re: Improving Python (was: Lambda going out of fashion)

In article <[EMAIL PROTECTED]>, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > >func(*arg) instead of apply() is a step back -- it hides the fact >that functions are objects, and it confuses the heck out of both >C/C++ programmers and Python programmers that understand the "def >func(*arg)" form, becau

Re: Improving Python (was: Lambda going out of fashion)

In article <[EMAIL PROTECTED]>, "Fredrik Lundh" <[EMAIL PROTECTED]> wrote: > func(*arg) instead of apply() is a step back Strongly disagree. I find func(*args) much more readable than apply(func, args). > -- it hides the fact that functions are objects, What does this have to do with anything

Re: Improving Python (was: Lambda going out of fashion)

Aahz wrote: >>(I've said it before, and I'll say it again: native unicode and >>generators are the only essential additions I've seen since 1.5.2, with >>properties and sub-classable C types sharing a distant third place. >>the rest of the stuff has had zero impact on my ability to write solid >>c

Re: Improving Python (was: Lambda going out of fashion)

In article <[EMAIL PROTECTED]>, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > >(I've said it before, and I'll say it again: native unicode and >generators are the only essential additions I've seen since 1.5.2, with >properties and sub-classable C types sharing a distant third place. >the rest of the

Re: Lambda going out of fashion

Nick Coghlan wrote: > And you're right, there is a behavioural difference - apply() expects a real > sequence, whereas the extended function call syntax accepts any iterable. > > However, there's also a bug in your demo code: I guess I must be getting over this cold -- I'm only 1/2 wrong this ti

Re: Lambda going out of fashion

Python 2.4 interactive session: Py> class Blah: ... def __iter__(self): ... yield "Test" ... Py> args = Blah() Py> apply(len, args) Traceback (most recent call last): File "", line 1, in ? TypeError: apply() arg 2 expected sequence, found instance Py> len(*args) 4 Py> class Blah(object): ..

Re: Lambda going out of fashion

Terry Reedy wrote: > Ok, add 'assuming that func and args are a valid callable and sequence > respectively.' Error messages are not part of the specs, and may change > for the same code from version to version. While true, the difference in error messages suggests that the two approaches use sl

Re: Lambda going out of fashion

Benji York wrote: > They do two different things. I think you have a spurious * in the call > to apply. The apply above is equivalent to D'oh! This cold has definitely made me error prone the last couple of days. Yesterday I managed to leave my cell phone in my pants pocket along with a coupl

Re: Lambda going out of fashion

Mike> Perl 6.0 is going to include even more drastic changes. It will Mike> also include a Perl 5.x interpreter, and will have to be switched Mike> to 6.0 mode by a magic cookie of some kind in the source. Possibly Mike> Python 3.0 could do something similar. -1 Things are compl

Re: Lambda going out of fashion

"Andrew Dalke" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Terry Reedy wrote: >> As far as I know, apply(func, args) is exactly equivalent to >> func(*args). > > After playing around a bit I did find one difference in > the errors they can create. Ok, add 'assuming that func a

Re: Lambda going out of fashion

Andrew Dalke wrote: Terry Reedy wrote: As far as I know, apply(func, args) is exactly equivalent to func(*args). After playing around a bit I did find one difference in the errors they can create. def count(): ... yield 1 ... apply(f, count()) Traceback (most recent call last): File "", lin

Re: Lambda going out of fashion

Nick Coghlan <[EMAIL PROTECTED]> writes: > jfj wrote: > Python 3.0 will be a case of "OK, let's take the things we learned > were good and keep them, and throw away the things we realised were > bad" > > Undoubtedly, the two languages will co-exist for quite some time. Perl 6.0 is going to includ

Re: Lambda going out of fashion

Terry Reedy wrote: > As far as I know, apply(func, args) is exactly equivalent to func(*args). After playing around a bit I did find one difference in the errors they can create. >>> def count(): ... yield 1 ... >>> apply(f, count()) Traceback (most recent call last): File "", line 1, in ? T

Dubious Python WAS: Re: Lambda going out of fashion

Fernando Perez said unto the world upon 2004-12-23 14:42: Alex Martelli wrote: I don't know what it IS about lambda that prompts so much dubious to absurd use, but that's what I observed. I don't know if that plays any role in Guido's current thinking, though -- I have no idea how much "dubious P

RE: Lambda going out of fashion

Stephen Thorne wrote: > Lambdas contain only a single expression. Even the py3k > wiki page ignores this critical difference. A single expression > means no statements of any kind can be included. Assignment, > if/elif/else, while, for, try/except, etc are not catered > for in lambdas. That's been

RE: Lambda going out of fashion

Nick Coghlan wrote: > ...rather than pushing to retain lambda for Py3K, it might > be more productive to find a better statement -> expression > translation for function definitions. Guido seems to prefer > named functions, so it would still be tough to gain his > acceptance. However, a more Python

Re: Lambda going out of fashion

<[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Well, you can say apply() is 'deprecated' now, What is deprecated is the spelling, not the concept or functionality. As far as I know, apply(func, args) is exactly equivalent to func(*args). If the latter had been invented in the begi

Re: Lambda going out of fashion

<[EMAIL PROTECTED]> wrote: > Thanks. :-) Two remarks. > o One-liner fits the eyes & brains of a portion of people. True! So, personally, I'd rather code, e.g., def bools(lst): return map(bool, lst) rather than breal this one-liner into two lines at the colon, as per standard Python style. How

Re: Lambda going out of fashion

Jp Calderone <[EMAIL PROTECTED]> wrote in news:[EMAIL PROTECTED]: > On Thu, 23 Dec 2004 13:36:08 GMT, rzed <[EMAIL PROTECTED]> wrote: >>Stephen Thorne <[EMAIL PROTECTED]> wrote in >> news:[EMAIL PROTECTED]: >> > [snip] >> > >> > { >> > 'one': lambda x:x.blat(), >> > 'two': lambda x:x.blah(),

Re: Lambda going out of fashion

Robin Becker wrote: Alex Martelli wrote: . By the way, if that's very important to you, you might enjoy Mozart (http://www.mozart-oz.org/) .very interesting, but it wants to make me install emacs. :( Apparently you can also use oz with a compiler and runtime engine...see http://www.mozart-o

Re: Lambda going out of fashion

Alex Martelli wrote: > I don't know what it IS about lambda that prompts so much dubious to > absurd use, but that's what I observed. I don't know if that plays any > role in Guido's current thinking, though -- I have no idea how much > "dubious Python" he's had to struggle with. Just a side com

Re: Switch statement (was: Lambda going out of fashion)

Skip Montanaro <[EMAIL PROTECTED]> wrote in news:[EMAIL PROTECTED]: > > Stephen> { > Stephen> 'one': lambda x:x.blat(), > Stephen> 'two': lambda x:x.blah(), > Stephen> }.get(someValue, lambda x:0)(someOtherValue) > > One thing to remember is that function calls in Python are >

Re: Lambda going out of fashion

Jp> PyStones may be short (and be nearly lambda free!) but it is one Jp> opaque blob to me. I'd be hard pressed to rewrite it in any style, Jp> given its perverse use of global state. It's written that way on purpose, of course. Pystone is almost a direct translation of a similar pr

Re: Lambda going out of fashion

On Thu, 23 Dec 2004 12:00:29 -0600, Skip Montanaro <[EMAIL PROTECTED]> wrote: > > >> While I'm sure it can be done, I'd hate to see a non-trivial Python > >> program written with lambda instead of def. > > Jp> What, like this? > > Jp> (lambda r,p,b:... > > Jp> OTOH, maybe

Re: Lambda going out of fashion

Skip Montanaro wrote: >Jp> OTOH, maybe that's still trivial, it's only a multiuser network >Jp> chat server, after all. > > You cheated by not rewriting Twisted using only lambda. isn't twisted already written with lambdas only? why else would they call it "twisted"? -- http:

Re: Lambda going out of fashion

"jfj" wrote: > Personally I'm not a fan of functional programming but lambda *is* useful > when I want to say for > example: > > f (callback=lambda x, y: foo (y,x)) > > I don't believe it will ever disappear. agreed. there's no reason to spend this christmas rewriting your programs, folks.

Re: Lambda going out of fashion

>> While I'm sure it can be done, I'd hate to see a non-trivial Python >> program written with lambda instead of def. Jp> What, like this? Jp> (lambda r,p,b:... Jp> OTOH, maybe that's still trivial, it's only a multiuser network Jp> chat server, after all. You che

Re: Lambda going out of fashion

[EMAIL PROTECTED] wrote: > o Why don't you just say all python can be written in equivalent java, your argumentation skills are awesome. -- http://mail.python.org/mailman/listinfo/python-list

Re: Lambda going out of fashion

Thanks. :-) Two remarks. o One-liner fits the eyes & brains of a portion of people. o Why don't you just say all python can be written in equivalent java, can I assert that Guido doesn't want to get mixed with those mainstream>? -- http://mail.python.org/mailman/listinfo/python-list

Re: Lambda going out of fashion

[EMAIL PROTECTED] wrote: I have this book called TEXT PROCESSING IN PYTHON by David Mertz on hand, it is a good book and in the first chapter it is really a show room for higher-order functions which I may now cite to remind you of the FLEXIBILITY of this keyword. I'm not exactly sure what you mean

Re: Lambda going out of fashion

I have this book called TEXT PROCESSING IN PYTHON by David Mertz on hand, it is a good book and in the first chapter it is really a show room for higher-order functions which I may now cite to remind you of the FLEXIBILITY of this keyword. ''' combinatorial.py from operator import mul, add, truth

Re: Lambda going out of fashion

Jp Calderone wrote: On Thu, 23 Dec 2004 10:19:33 -0600, Skip Montanaro <[EMAIL PROTECTED]> wrote: While I'm sure it can be done, I'd hate to see a non-trivial Python program written with lambda instead of def. What, like this? [snip horrible lambda expression] OTOH, maybe that's still trivial,

Re: Improving Python (was: Lambda going out of fashion)

Skip Montanaro wrote: > >Keith> My personal gripe is this. I think the core language, as of 2.3 >Keith> or 2.4 is very good, has more features than most people will ever >Keith> use, and they (Guido, et al.) can stop tinkering with it now and >Keith> concentrate more on the standard

Re: Lambda going out of fashion

On Thu, 23 Dec 2004 10:19:33 -0600, Skip Montanaro <[EMAIL PROTECTED]> wrote: > > >> readability. Pythonic lambdas are just syntactic sugar in practice, > > Paul> Actually it's the other way around: it's named functions that are > Paul> the syntactic sugar. > > While I'm sure it can b

Re: Lambda going out of fashion

>> readability. Pythonic lambdas are just syntactic sugar in practice, Paul> Actually it's the other way around: it's named functions that are Paul> the syntactic sugar. While I'm sure it can be done, I'd hate to see a non-trivial Python program written with lambda instead of def. (

Re: Lambda going out of fashion

Craig> IMO the reference behaviour of functions in the C API could be Craig> clearer. One often has to simply know, or refer to the docs, to Craig> tell whether a particular call steals a reference or is reference Craig> neutral. Take, for example, PyDict_SetItemString vs Crai

Improving Python (was: Lambda going out of fashion)

Keith> My personal gripe is this. I think the core language, as of 2.3 Keith> or 2.4 is very good, has more features than most people will ever Keith> use, and they (Guido, et al.) can stop tinkering with it now and Keith> concentrate more on the standard libraries. What keeps you

Switch statement (was: Lambda going out of fashion)

Stephen> { Stephen> 'one': lambda x:x.blat(), Stephen> 'two': lambda x:x.blah(), Stephen> }.get(someValue, lambda x:0)(someOtherValue) One thing to remember is that function calls in Python are pretty damn expensive. If x.blat() or x.blah() are themselves only one or two lines

Re: Lambda going out of fashion

On Thu, 23 Dec 2004 13:36:08 GMT, rzed <[EMAIL PROTECTED]> wrote: >Stephen Thorne <[EMAIL PROTECTED]> wrote in > news:[EMAIL PROTECTED]: > > [snip] > > > > { > > 'one': lambda x:x.blat(), > > 'two': lambda x:x.blah(), > > }.get(someValue, lambda x:0)(someOtherValue) > > > > The alternatives to

Re: Lambda going out of fashion

Stephen Thorne <[EMAIL PROTECTED]> wrote in news:[EMAIL PROTECTED]: > Hi guys, > > I'm a little worried about the expected disappearance of lambda > in python3000. I've had my brain badly broken by functional > programming in the past, and I would hate to see things suddenly > become harder than

Re: Lambda going out of fashion

On Thu, 23 Dec 2004 13:47:49 +0100, Alex Martelli <[EMAIL PROTECTED]> wrote: > Nick Coghlan <[EMAIL PROTECTED]> wrote: >... > > Perhaps something like: > > > > accepts_func( (def (a, b, c) to f(a) + o(b) - o(c)) ) > > Nice, except I think 'as' would be better than 'to'. 'as' should be a > ful

Re: Lambda going out of fashion

Nick Coghlan wrote: Indeed, lambda as it currently stands will disappear for the Python 2.x series. Will NOT disappear. I repeat, will NOT disappear. Cheers, Nick. Damn those missing negators. . . -- Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia ---

Re: Lambda going out of fashion

Alex Martelli wrote: Nick Coghlan <[EMAIL PROTECTED]> wrote: ... Perhaps something like: accepts_func( (def (a, b, c) to f(a) + o(b) - o(c)) ) Nice, except I think 'as' would be better than 'to'. 'as' should be a full keyword in 3.0 anyway (rather than a surprisingly-NOT-keyword like today), a

Re: Lambda going out of fashion

Alex Martelli wrote: . By the way, if that's very important to you, you might enjoy Mozart (http://www.mozart-oz.org/) -- I'm looking at it and it does appear to go even further in this specific regard (rich support for multi - paradigm programming). It's also blessed with a great book,

Re: Lambda going out of fashion

Fredrik Lundh wrote: Craig Ringer wrote: It's hard to consistently support Unicode in extension modules without doing a lot of jumping through hoops. Unicode in docstrings is particularly painful. This may not be a big deal for normal extension modules, but when embedding Python it's a source of

Re: Lambda going out of fashion

Nick Coghlan <[EMAIL PROTECTED]> wrote: ... > Perhaps something like: > > accepts_func( (def (a, b, c) to f(a) + o(b) - o(c)) ) Nice, except I think 'as' would be better than 'to'. 'as' should be a full keyword in 3.0 anyway (rather than a surprisingly-NOT-keyword like today), and "define som

Re: Lambda going out of fashion

jfj wrote: Stephen Thorne wrote: Hi guys, I'm a little worried about the expected disappearance of lambda in python3000. I've had my brain badly broken by functional programming in the past, and I would hate to see things suddenly become harder than they need to be. Don't worry, it's not gonna go a

Re: Lambda going out of fashion

Peter Otten <[EMAIL PROTECTED]> wrote: > Alex Martelli wrote: > > > if len(somecontainer) > 0: > > > > instead of the obvious > > > > if somecontainer: > > > > so it's not as if pythonistas in general are blessed with some magical > > "redundancy avoidance spell"... > > That is not always eq

Re: Lambda going out of fashion

Stephen Thorne wrote: Hi guys, I'm a little worried about the expected disappearance of lambda in python3000. I've had my brain badly broken by functional programming in the past, and I would hate to see things suddenly become harder than they need to be. Don't worry, it's not gonna go away because

Re: Lambda going out of fashion

Fredrik Lundh <[EMAIL PROTECTED]> wrote: > Alex Martelli wrote: > > > I think I'll scream, though not quite as loud as for my next seeing: > > > > map(lambda x: f(x), ... > > > > instead of > > > > map(f, ... > > note that if you replace "map" with "some function that takes a callable", > the di

Re: Lambda going out of fashion

Alex Martelli wrote: > if len(somecontainer) > 0: > > instead of the obvious > > if somecontainer: > > so it's not as if pythonistas in general are blessed with some magical > "redundancy avoidance spell"... That is not always equivalent: >>> z = Numeric.zeros(5) >>> z array([0, 0, 0, 0, 0])

Re: Lambda going out of fashion

Alex Martelli wrote: > I think I'll scream, though not quite as loud as for my next seeing: > > map(lambda x: f(x), ... > > instead of > > map(f, ... note that if you replace "map" with "some function that takes a callable", the difference between these two constructs may be crucially important.

Re: Lambda going out of fashion

Alan Gauld <[EMAIL PROTECTED]> wrote: ... > It can't be that hard to maintain the lambda code, why not just > leave it there for the minority of us who like the concept? I guess the key motivator is the usual set of design principles: 3. Keep the language small and simple.

Re: Lambda going out of fashion

Alan Gauld wrote: It can't be that hard to maintain the lambda code, why not just leave it there for the minority of us who like the concept? Because one of the points of Py3K is to clean up the language concepts and syntax, and the current lambda just doesn't fit cleanly. If it was proposed in a

Re: Lambda going out of fashion

Stephen Thorne wrote: > Not true, you can't re-write > > def f(): >raise ValueError, "Don't call f" f = lambda: eval(compile("raise ValueError(\"Don't call f\")", "", "exec")) note that lambdas have names too, btw: print f.func_name -- http://mail.python.org/mailman/list

Re: Lambda going out of fashion

On 23 Dec 2004 00:52:53 -0800, Paul Rubin <"http://phr.cx"@nospam.invalid> wrote: > Alan Gauld <[EMAIL PROTECTED]> writes: > > readability. Pythonic lambdas are just syntactic sugar in > > practice, > > Actually it's the other way around: it's named functions that are the > syntactic sugar. Not t

Re: Lambda going out of fashion

Craig Ringer <[EMAIL PROTECTED]> wrote: ... > Couldn't agree more. One of the things I find most valuable about Python > is the ability to use functional style where it's the most appropriate > tool to solve a problem - WITHOUT being locked into a pure-functional > purist language where I have t

Re: Lambda going out of fashion

Alan Gauld <[EMAIL PROTECTED]> writes: > readability. Pythonic lambdas are just syntactic sugar in > practice, Actually it's the other way around: it's named functions that are the syntactic sugar. -- http://mail.python.org/mailman/listinfo/python-list

Re: Lambda going out of fashion

On 22 Dec 2004 23:21:37 -0800, [EMAIL PROTECTED] wrote: > but if lambda keyword is removed, I swear I will not use the python > anymore. While I would be dissappointed to lose lambda, I think losing Python would hurt me a lot more! After all we aren't losing functionality here, just adding sonme

Re: Lambda going out of fashion

On Thu, 23 Dec 2004 14:13:28 +1000, Stephen Thorne <[EMAIL PROTECTED]> wrote: > I'm a little worried about the expected disappearance of lambda in > python3000. I've had my brain badly broken by functional programming > in the past, and I would hate to see things suddenly become harder > than they

Re: Lambda going out of fashion

Keith Dart <[EMAIL PROTECTED]> wrote: > My personal gripe is this. I think the core language, as of 2.3 or 2.4 > is very good, has more features than most people will ever use, and they Indeed, it has _too many_ features. Look at the PEP about 3.0, and you'll see that removing redundant features

Replacing lambda() examples... (Re: Lambda going out of fashion)

-examples of using or not using the lambdas. While following the thread "Lambda going out of fashion" I have read cries for not throwing lambdas away and also the opposite opinions. I believe that the theme requires more examples to convince. I personally incline towards the experience of Cr

Re: Lambda going out of fashion

Craig Ringer wrote: > It's hard to consistently support Unicode in extension modules without > doing a lot of jumping through hoops. Unicode in docstrings is > particularly painful. This may not be a big deal for normal extension > modules, but when embedding Python it's a source of considerable

Re: Lambda going out of fashion

On Thu, 2004-12-23 at 15:21, [EMAIL PROTECTED] wrote: > This is NOT true. Functional programming, AFAIKC, is a cool thing, and > in-fashion, increases productivity & readability, and an indispensable > thing for a flexible scripting lang. Couldn't agree more. One of the things I find most valuable

Re: Lambda going out of fashion

[EMAIL PROTECTED] wrote: Well, you can say apply() is 'deprecated' now, (which is another functional thing I like), but I am still using it. Interesting. Could you explain why? Personally, I find the *expr/**expr syntax much simpler, so I'd be interested in knowing what motivates you to continu

Re: Lambda going out of fashion

On Thu, 2004-12-23 at 12:47, Keith Dart wrote: > On 2004-12-23, Stephen Thorne <[EMAIL PROTECTED]> wrote: > > Hi guys, > > > > I'm a little worried about the expected disappearance of lambda in > > python3000. I've had my brain badly broken by functional programming > > in the past, and I would hat

Re: Lambda going out of fashion

This is NOT true. Functional programming, AFAIKC, is a cool thing, and in-fashion, increases productivity & readability, and an indispensable thing for a flexible scripting lang. The inline/lambda function is feature is shared by many lang. which I frequently use, MATLAB/R/Python/etc. Well, you can

Re: Lambda going out of fashion

Stephen Thorne wrote: { 'one': lambda x:x.blat(), 'two': lambda x:x.blah(), }.get(someValue, lambda x:0)(someOtherValue) The alternatives to this, reletively simple pattern, which is a rough parallel to the 'switch' statement in C, involve creating named functions, and remove the code from the co

Re: Lambda going out of fashion

On 2004-12-23, Stephen Thorne <[EMAIL PROTECTED]> wrote: > Hi guys, > > I'm a little worried about the expected disappearance of lambda in > python3000. I've had my brain badly broken by functional programming > in the past, and I would hate to see things suddenly become harder > than they need to

Lambda going out of fashion

Hi guys, I'm a little worried about the expected disappearance of lambda in python3000. I've had my brain badly broken by functional programming in the past, and I would hate to see things suddenly become harder than they need to be. An example of what I mean is a quick script I wrote for doing c