[Python] Python vs. Io

"Daniel Ehrenberg" <LittleDanEhren at yahoo.com> wrote in message
news:711c7390.0401291301.3f95794 at posting.google.com...

I think Daniel's example is a little bit more complicated than that. It
resembles more closly the lisp-ish macros that were discussed to death a
while ago.

Note that in his code:
each((key, value) in map(x=1, y=2, z=3),
write(key, ": ", value, "\n")
)

key and value are variable names that get used inside the function call.

Here is my pythonic(?) version, however it requries a lambda to bind the
variable names.

def map(**kw):
return kw.items()

def each(seq, func):
for v in seq:
apply(func, v)

from sys import stdout
write = stdout.write

each(map(x=1,y=2,z=3),
lambda key, value: write("%s: %s\n"%(key, value)))

Brian

Hey, if I wanted to to, I could add functions and all that that would
make Python look like Lisp, or IO, or whatever.

But, why? If I wanted to write Lisp or Io, I'd use those.

Your example I'd write in Python as

for key, value in dict(x=1, y=2, z=3):
print '%s: %s\n" % (key, value)

I didn't have to write 43 lines of support code, and it's also two
lines. I don't think "this isn't builtin" is a selling point -- you
need a critical mass of builtins to make a language useful.
Ok, these two points are window-dressing: minor spelling and
punctuation issues (which seems to be what most language wars are about).

Heck, use boost::python for C++ interfaces; those function names are
even shorter. Or use pyrex to generate wrappers, writing them in a
Pythonesque language.
Can you elaborate a bit on why Python is inflexible? I find Python to
be extremely flexible.
Python is 14 years old, and it's still working on global domination;
Io's got some catching up to do :-)

--
/--------------------------------------------------------------------------\

[snip-a-lot]
Using any language (other than a Lisp) which is sufficiently powerful
mostly comes down to personal preference regarding syntax. Library and
community support will of course grow for new languages if enough
people find it 'fits their minds' better than anything previously
available.
If inflexibility means not being able to arbitrarily change the
syntax, then I'm all for it, because it does help consistency and
readability, which I like very much in my programs, especially when
not working on them alone... Python seems to have found a good middle
ground between strictness and dynamism.
If I wanted a 'flexible' language, I'd use Lisp, or Forth.

I know. Maybe in the future, it can be builtin, but it just shows how
flexible Io is. Io has its own version of a for loop (in addition to
being able to iterate directly over a dictionary or list) which in
some cases makes more sense than Python's. It's like this:

for(x, 1, 10, #goes through x with values 1-10
write(x, "\n")
)

IMHO, this makes more sense than iterating over a list created just
for a specific loop. On my computer, Io's loops are faster than
Python's (probably because they are lazy).
But the community will grow larger in time. The Io community is bigger
than the Python community two years after Python was released
(although that's probably because it wasn't publicly released for two
years).
There's still a difference between types and classes in Python. Try
this in Python:
It raises an error. But the same thing in Io works (which is x :=
Object clone; x number := 5). To do it in Python, you have to do
Also, Python has statements (as opposed to just expressions) even for
the simplest things like writing things to the command line. In Io,
flow control is in functions, which can be overwritten if you want to
change them. The Python philosophy is that if you allow this and other
flexible things to happen, you will have inconsistent code. If someone
asks on the Tutor mailing list how to change that, everybody responds
"Why would you want to do that?". While that's a valid viewpoint, it's
not the most flexible.
I don't think world domination is a practical goal for either
language.

Daniel Ehrenberg

Haven't you heard of xrange? It's like range, only without the list
instantiation (and a few other things).

I would also be willing to bet that is due to the ease of distribution
that the modern internet allows, coupled with the current geek-chic of
learning new-better-than-ever languages. Heck, brainfuck probably has
more users than Python did 2 years after its introduction, but that
doesn't mean that you will be able to write programs that are better,
more efficient, easier to update, easier to debug, etc., with BF than
with some other newer language.

Perhaps it isn't more flexible. On the other hand, it does allow anyone
to read your code and know that there isn't any magical syntax that is
usable on one Python x.y installation, that isn't on another.

- Josiah

What are you talking about? There's tons of new "magical syntax" in
Python. Examples for "magical syntax" features that don't work on
1.5.2 include:
*List comprehensions
*String methods
*Generators
*Emulating numeric types
*Nested scopes
* * and ** in function declarations
*for line in this_file
*Subclassing types

There's tons of stuff still being added to Python.

Daniel Ehreberg

Nope. The syntax is identical. Strings just happen to have more useful
attributes new.
Hmm. Not really a syntactic difference... The syntax is the same, after
all, but the behavior is definitely different.
Nope. Same as with strings, the iterator protocol, a set of methods with
a defined meaning, was added, and file objects were made to implement it.
No syntactic changes.
This is another iffy one. The syntax is no different, the behavior has
just been changed. "str", "int", etc, used to be builtin functions, not
type objects. You also couldn't subclass types in Python, but if you could
have, the syntax would have been identical to what it is today.
Definitely. But "stuff" isn't always the same as "magical syntax".

Jp

[...]
* and ** in function _calls_ is new in 2.0, but in declarations was already
there in 1.5.2:

bash-2.05b$ python1.5
Python 1.5.2 (#0, Jul 5 2003, 11:45:08) [GCC 3.3.1 20030626 (Debian prerelease)] on linux2
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
... print args, kwargs
...
('a', 'b', 'c') {'z': 3, 'x': 1, 'y': 2}
>>>

-Andrew.

"Daniel Ehrenberg" <LittleDanEhren at yahoo.com> wrote in message
news:711c7390.0401311220.763be80a at posting.google.com...
[snip]
[snip]

Syntax that can be used on one Python x.y.z installation, can
be used on another installation of the _same_ version (x.y.z)
of Python.

I've always presumed that if I wanted an ultra-pure OO language I would
use Smalltalk. Obviously IO's big difference is prototype rather than
class-based inheritance. But that's a difference, not (necessarily) a
benefit. Could you please describe what would attract one to IO over
Smalltalk?

Paul Prescod

By that logic, anything that can be implimented in the language isn't
"magical syntax". In Io, there is no difference between flow control
and functions, so it's not "magical syntax" and it's just "stuff".

Daniel Ehrenberg

As mentioned by Sean Ross, I was talking about Python x.y compatibility
with other copies of version x.y. With the way you describe IO, it
encourages people to customize flow control and syntax. Such
customization does not necessarily increase readability, usability, or
write-once-run-anywhere with IO version u.v. It may also fragment the
language in the long run into different camps; those that like the slim
version, and those that like a version with every modification they can
find.

- Josiah

In short, Io isn't as "ultra-pure" as Smalltalk. Here are some things
that Io supports and Smalltalk doesn't:
*Standard operator precedence
*Normal function syntax
*Standalone functions
*Everything is public (like Python)
*Interpreted and no monolithic system image like Smalltalk
*Better block syntax (no cryptic square brackets or variable symbols)
*Prototypes (which *is* a benefit, not just a difference)
*Not obsessively object oriented (for stuff like flow control)
*Growing, not shrinking community
*Inplace mathematical operations
*Much smaller implimentation and good for embedding
*More flexible for syntax extension
*Everything is anonymous (yet there is still some introspection for
names)
*Functions are first class objects, not merely messages
*The ability to change what it inherets from
*More flexible scoping
*Writing self can be left out when sending messages to the current
object
*Speed on par with Python
*Optionally non-strict functions (but usually strict anyway)

Note that Python lacks some of these things too.

Daniel Ehrenberg

This is because instances of object don't have a __dict__, but instances
of goodObject do. Says the new-style objects document:
Instances of a class that uses __slots__ don't have a __dict__
(unless a base class defines a __dict__); but instances of
derived classes of it do have a __dict__, unless their class
also uses __slots__.

object has slots=[], effectively. The behavior is much like what you'll
see in the example below:
class S(object): __slots__ = ['x']
class T(S): pass

s = S()
s.x = 1 # succeeds
s.y = 2 # fails with exception

t = T()
t.y = 3 # succeeds

Now, whether it's good to have __slots__ and __dict__ I can't tell you,
but it's this wrinkle that caused the behavior you saw, not a
"difference between types and classes".

Jeff

No, you cannot introduce new special forms (i.e., statement syntax) in
Python without modifying the Python interpreter itself.

There are two major camps in language design. One says that you should
be able to modify the language itself to your will, and the other says
that this gets rapidly confusing and you shouldn't. They're simply
different camps, and the two camps won't agree. Furthermore, the
ability to convert a language from the second camp to the first is not
without difficulty; such things usually have to be designed into the
language from the scratch, or you end up with a very complicated process
of creating hygienic macros.

This is a situation where Io is in the first camp and Python is in the
second. They simply don't have equivalent goals; Python emphasizes
transparency and readability more than customizability and flexibility,
whereas Io does the opposite.
These are really stylistic objections, as are the other objections you
list below. That's completely fine, of course; you should choose a
language that jives with your personal sense of language style. But
language designers need to make decisions, and those decisions are
necessarily going to eliminate some styles of programming, while
emphasizing others.

You're in a situation where it sounds like Io jives with your sense of
style more than Python. That's perfectly fine, and I know from my own
research that Io is a neat little language (though I haven't really used
it for anything substantial yet). But you can't expect other languages
to bend to your personal will and personal sense of style, particularly
when it means necessarily violating someone else's corresponding senses.

Io and Python have quite different fundamental approaches to language
design, and so it's not surprising that there are going to be
irreconcilable differences.

I long to live in a world where Python is considered a crufty incumbent
legacy language that is forced on unwilling programmers by Pointy Haired
Bosses. First, it would mean that Python has vanquished languages that
programmers like less. Second, it would mean that the up-and-coming
languages are so unbelievably cool and elegant that they make Python
look like a lumbering dinosaur.

Thanks for reminding me that that that day was once unfathomably far in
the future and now seems almost around the corner!

But when I look closer at IO it seems to me that the day is not as near
as I hope. If you wish to hasten I urge you to:

* finish the IO tutorial
* distribute windows binaries of IO
* make IO compilers to C and Java available
* make bindings to popular windowing toolkits
* make bindings to Java, .NET, COM, SOAP, XML-RPC etc.
* use IO in a production context so that the rest of us can have faith
in its stability
* implement MySQL and Oracle bindings
* publish some books on IO
* point me to some documentation on how to launch and kill processes in IO

If this were all done tomorrow I might be tempted to jump over to IO but
I would be amazed if it were all done even two years from now.

Also, an observation: IO's syntactic simplicity looks to me to be both a
blessing and a curse.

Paul Prescod

As other posts have indicated, this is not the io-user-list. While
you probably have good, purely academic intentions with your post,
this is not the correct forum. Create an io-vs-python list somewhere
and I'm sure you'll get a few subscribers. :)

Hi.
I took a look at Io because of your post, and I have a question:

Are there prototype(?) _and_ instance methods/slots?

In other words, is there a shared state mechanism between instances of a
prototype?
If so, could you show an example.

Thanks,
Sean

"Sean Ross" <sross at connectmail.carleton.ca> wrote
I'm not sure how to tell you this so I'll just give a heavily
commented example (comments in Io are with #, //, or /* */)

parentProto := Object clone //makes parentProto a new object
//:= is used for creating new variables
parentProto shared := 5 //parentProto's new slot shared holds 5
parentProto different := 6
parentProto sum := method(shared + different) //self isn't necessary
write("parentProto's sum: ", parentProto sum, "\n")
x := parentProto clone //essentially new instance of parentProto
y := parentProto clone
x different = 2 //just updating slots is done with =.
y different = 3
write("first x sum ", x sum, "\n",
"first y sum ", y sum, "\n")
parentProto shared = 7 //should show up on all clones
write("later x sum", x sum, "\n",
"later y sum", y sum, "\n")

Does that illustrate it well? I know the difference between := and =
is annoying, but you'll get used to it, and it allows really cool
things to be done with scopes and inheretance.

Daniel Ehrenberg

"Daniel Ehrenberg" <LittleDanEhren at yahoo.com> wrote in message
news:711c7390.0401301726.3e38da27 at posting.google.com...
[snip example]
I think I get the idea. Let's see:

P = Object clone do( # saw do() used in iolanguage mail archive
allocated = 0
init = method(
id := allocated # semi-colons required?
allocated += 1
)
howMany = method(return allocated)
)

x := P clone
y := P clone
write("allocated? ", P howMany())
# output ...
# allocated? 2

Correct?

Thanks for making me aware of this language, it has some
interesting ideas. I'm not annoyed by the difference between :=
and =. I understand the issue(s) they're trying to solve: you don't
need to declare local variables, or use self, explicitly. I don't have
a problem with that. I imagine it could lead to subtle bugs (if you
update a slot when you meant to set a new one), but that is only
speculation on my part.

I'm not a fan of the parenthesis (which might be expected from
a Python user - love that significant whitespace ;). I'm also not a
big fan of 'clone', I'd rather see 'new', but I do understand why
'clone' is more apt. Of course, in this language, you could always
just say

Object new = Object getSlot("clone")
P = Object new
...

I can appreciate the flexibility of that.

No, init and allocated should have used :=, even though init has
special meaning. I don't really know why you have the howMany method
since it doesn't really do anything (everything is public and methods
can be called with just references), and all clones of P will
dynamically inheret allocated. Also, when initializing variables,
their scope must be specified (which is the whole reason for the
difference between := and =), so id := allocated should probably be
self id := allocated. self, along with a few other variables, is
implicitly sent to all functions (and do).
Actually, the whole scoping model is really that you're working in
transparent objects with inheretance, even for things like the global
scope and the scope of functions.
At first I didn't like them easier, and with the syntax of most
languages, there really isn't any advanatage, but Io code by
convention can be much more dense (while still readible). For example,
Io doesn't have a ternary operator (like Python), but the flow control
function if can be used like one. For example:

x := if(Nil, 1, 0)

would set x to 0. Note that only Nil (and things that emulate Nil) are
false in the context of if.
Yeah, that is an advantage. That way of using 'new' will be inhereted
dynamically for all objects.

Daniel Ehrenberg

"Daniel Ehrenberg" <LittleDanEhren at yahoo.com> wrote in message
news:711c7390.0401311134.26cd0a11 at posting.google.com...
[snip]
Okay. So, is there no way to have private attributes/operations?
Or, like in Python, is there just a convention? "_slotName"

[snip]
Okay. So, if I set 'self id', like so

self id := allocated

and want to update it later in the same block I can use

id = "updated self 'id' slot value"

But, if I later use

id := "set new local 'id' slot value"

in the same block I get a new local variable. Is that how it works?
Or does the first use of a slot determine its assignment scope
for the duration of the block?

self a := "unchanged"
a := "changed"
write("self a is ", self a) # changed or unchanged?

Yes, but code like that is confusing and shouldn't be used unless you
need to.
unchanged.

If you want to learn more about Io, you should probably join the Io
mailing list instead of bothering the whole usenet thread. Its website
is http://groups.yahoo.com/group/iolanguage/ .

Daniel Ehrenberg

After looking at your sample code, I couldn't help but say 'ick'. Maybe
it is my C and Python background, but just putting a space between an
object and its properties looks ugly. The use of method() also makes my
skin crawl.

It is cool that you dig on Io, and I wish you the best.

- Josiah

Do you know why the creator of IO decided not to use the now-ubiquitous
"." operator? I don't know whether I can define a "." operator that has
the appropriate behaviour but that wouldn't help anyhow.

Paul Prescod

"Paul Prescod" <paul at prescod.net> wrote in message
news:mailman.1078.1075571238.12720.python-list at python.org...
As far as I know, since everything is a "message send", the dot
is unnecessary. Every operation is either object.paremeter(s),
or syntactic sugar that gets transformed into that format.

John Roth

In the opinion of the creators of Io, a space looked cleaner. Using a
period looks kinda like you're finishing a sentence and starting a new
one. Consider the following syntaxes:

Dog barks //Io
Dog.barks() #Python

Regardless of which one is more common, which looks more like
language?
You say that "." is more ubiquitous, but "{}" is more ubiquitous than
":" by far, yet Python uses the latter and we don't complain. (note
that in Io, unlike other languages with similar syntax such as Ruby,
functions are first class objects.)

Daniel Ehrenberg

Interesting. I would never name a method like that because it is not
immediately clear to me whether the method is imperative of interrogatory.

The dog barks (Are you asking or telling the dog?)
Bark dog (You are definitely telling the dog something)
Dog, are you barking (You are definitely asking the dog)

So I'd write:

Dog barking
Dog bark

Cheers,
Brian

Looking like natural language is *not* necessarily a good thing in
programming languages.

Ok, which one looks more intuitive, then? Both languages are
turing-complete and Io's easy syntax doesn't hamper it in the way that
BASIC's intuitive but limited syntax does.

Daniel Ehrenberg

The space "operator" is used in way too many different ways in language.
Consider these two grammatical sentences:

The Dog barks. (how IO uses the space)
The Dog Spot. (how Java/C/C++ use the space)

But anyhow I'm not going to argue that IOs choice is wrong, just
confusing at first.
First, if I had invented Python I would not have bothered to buck the
trend of using curly braces. Hardly anyone chooses Python because of
that feature and some are turned off by it. Python makes tons of
conservative, "traditional" choices and I think that they do have
something to do with its current level of popularity. Sometimes Python
even hides pretty radical semantics under "traditional" syntax (e.g. []
as sugar for getitem). Ruby takes this even farther. If I were in charge
of IO I might do that too. e.g. make {} sugar for a last argument that
is a statement list or something.

Second, I think that the meaning of Python's colon is unuusal but
self-evident. I personally decided to learn Python because I stumbled
upon some code that looked exactly pseudo-code and wondered what
language I was reading. Coming from (e.g.) Java or C++, most of Python's
surfact syntax is self-evident to the English speaker, even when
different (e.g. "or" instead of "||").

Language design is like music composition. You must be better than your
competitors but no so much better (i.e. different) that you just seem
"weird". Judging the right balance is not easy.

Paul Prescod

Paul Prescod wrote:

...snip...
...snip...


Not that this invalidates your point, as I still fall into the category of
'hardly anyone'; but, the indentation-identified block is precisely the
reason I first tried Python. Having used Occam for many years, I was very
pleased to find a language that recognized the superiority of that style.


--Andy

I have to admit that the indentation feature turned me off at first, but
having used Python for a while now, I find that method superior to the
curly braces approach. Much more DWIM.

"Paul Prescod" <paul at prescod.net> wrote in message
news:mailman.1110.1075672228.12720.python-list at python.org...
I suppose I am hardly anyone else, since that it exactly what
attracted me to Python. In fact, I will take partial responsibility
for the indentaion syntax in IBM's ISPF mini-language - it's a
preferance of long standing with me.

Now that I actually have a significant language using them, I
can see that there are a couple of things they make more
difficult, statement syntax embedded within expressions being
one. The other is a rather esoteric issue with clauses like
elif, else and except.

John Roth

There are certainly costs and benefits to the Python way. And we've been
over them many times. ;)

I'm just saying that from a language popularity point of view,
"different" is usually perceived as "worse" unless it is really vastly
better.

Paul Prescod

Another thought about that: from the Python version, barks is
evidently a function. Even if were a data attribute, I think
in classical usage it would be a "message", and given that a
class instance can implement its own attribute lookup, we may
as well say that data attributes are simply functions with no
extra parameters.

So, how odd that anyone would think of putting the function
AFTER the object. Did this come from Forth or something?

In the above example it looks somewhat natural, but only
because of a declarative flavor that is hardly the rule in
OO programming. Take wl.append(w), for example - we're so
used to this notation there's no point in asking if it would
make more sense written append.wl(w), but if we're looking
at a language that has taken a more lispish notation, I'd
suggest "append wl w" is far more consonant with normal
(not Forth) programming language notation.

That leads to an interesting generalization. Take a common
thorn out of Python's hide: "join sep wl". Is "join" a member
function of sep, or a plain function? Well, who cares? If
sep has a join function, it should apply in this case, but if
not, there's a generic. In essence, all functions with 1 or
more arguments are "member" functions - either of the class
in which they're declared, or of the generic object class at
the top of the object hierarchy.

Donn Cave, donn at drizzle.com

Dog is not just the object. It is also the namespace that "barks" comes
from. Both the computer and the human need to know the namespace before
they can interpret the meaning of the string "barks" so it seems natural
to me that it should come first. This is especially true in languages
like Python and IO where two objects of even the same type could have
different name->method mappings.

Paul Prescod





From http Sun Feb 1 22:17:07 2004
From: http (Paul Rubin)
Date: 01 Feb 2004 13:17:07 -0800
Subject: OT: why do web BBS's and blogs get so slow?
References: <7xbrojk9rk.fsf_-_@ruckus.brouhaha.com>
<m2ad42342e.fsf@david-steuber.com>
Message-ID: <7xad421ovg.fsf@ruckus.brouhaha.com>

David Steuber <david.steuber at verizon.net> writes:
Yes, it's a BBS, not a data mining system. There should be few if any
long-running transactions. Maybe some occasional complicated requests
would get spun off to a new thread or even just forked off. The
server would run normal requests to completion before going on to the
next request.
Maybe. Using mmap does avoid a lot of system calls/context switches.

In your advocacy of Lisp over Forth (something completely unrelated to
this thread and newsgroup), you miss the major selling point of object
orientation: encapsulation. If you had barks(Dog) instead of
Dog.bark() (I'm using Python not Io syntax for now), bark() is
accessible to everyone, not just Dogs. So I could write bark(Cat),
which shouldn't work. Also, some of your examples of things that are
ambiguous really aren't ambiguous because neither Python nor any other
language uses spaces both in the way they are used in Lisp and the way
they are used in Smalltalk.

Daniel Ehrenberg

Quoth LittleDanEhren at yahoo.com (Daniel Ehrenberg):
...
You're not only using Python syntax, you're using its rules
for function namespaces, and that wasn't exactly what I had
in mind.

In Python, we know that obj.fun() looks for fun in obj, and we
know the reverse is generally true - to invoke fun in obj, we
write obj.fun(). But there are functions like repr or "+" that
end up deferring to their parameters' member functions. When we
write str(obj) instead of obj.str(), we're hopefully not kidding
ourselves that there's some profound distinction between these two
notations. Still less in a hypothetical language whose syntax
is different.

There are plenty of cases in anyone's Python code where a plain
function could have been a method of its parameter, or vice versa,
flip a coin. Why do I have to go through all my code and change
flip(coin) to coin.flip(), or vice versa? It's an implementation
detail that no one but the implementor should have to care about.

Donn Cave, donn at drizzle.com

Quoth Paul Prescod <paul at prescod.net>:
If as a human I need to know the namespace of a function to understand
it, am I going to be confounded if a function defined in SGMLParser
appears to be invoked on an instance of HTMLParser? Well, honestly
that kind of thing can sometimes be a source of frustration, but in
principle we prefer to consider it a virtue of the system, right?

Taking the "feed" function there, for example -
parser.feed(data)

In principle, it already could be one of
HTMLParser.feed
SGMLParser.feed
ParserBase.feed
object.feed

and this is fine, we're not supposed to have a problem with it.
But if the feed function had been outside this hierarchy, we would
be writing instead
feed(parser, data)

Why isn't that a violation of the object abstraction? Simply make
it generic and let the above notation serve in either case, and you
don't have to know the implementation in order to use it.

Now I'll admit that this level of abstraction does pose a problem
with scope and legibility, and that might have to be addressed.
My point though is that we already accept this problem as a cost
of doing OO business, so it's kind of surprising to me that OO
languages invariably stop there, instead of going all the way.
They'll proudly declare that `everything is an object', but don't
wonder about the distinction between functions and methods.

Once you get far enough down the path that you have `languages
like Python and IO', you have some semantics that would be an
awkward fit here. Two objects of the same could have different
name->method mappings, indeed. But it's far from obvious that
this is even a good thing, let alone the obvious evolution of OOP.

Donn Cave, donn at drizzle.com


From nomail Mon Feb 2 08:00:59 2004
From: nomail (BG)
Date: Mon, 2 Feb 2004 08:00:59 +0100
Subject: bsddb.dbshelve problem unpickling objects from another directory
References: <401d7d15$0$3257$58c7af7e@news.kabelfoon.nl>
<bvk2t3$q5h$1@news.service.uci.edu>
Message-ID: <401df5c2$0$3244$58c7af7e@news.kabelfoon.nl>

Josiah,

Thank you for your quick answer. But, this very much limits the way
persistent objects can be used. Objects can apparently only be used in the
context they were created. There is a logic to this, but it is also strange
to me. Is there a way that upickled objects can also be used outside there
original context?

Berry.

"Josiah Carlson" <jcarlson at nospam.uci.edu> schreef in bericht
news:bvk2t3$q5h$1 at news.service.uci.edu...
is
be
The

"Donn Cave" <donn at drizzle.com> wrote in message news:<1075702864.490920 at yasure>...
to access privileges and the visible implications of the code.

feed(parser, data) implies that feed has equal access privileges to
both parser and data, and that parser and data are unchanged by the
operation. It's vaguely saying "I want something to happen based on
parser and data".

parser.feed(data) implies that feed has enhanced access privileges to
parser compared to its access to data. In particular it implies that
parser maintains some sort of state and that data is just an argument.
It's saying "I want parser to do something based on data".

In Python this is mainly just a semantic issue since you don't have
the rigorous public/private/protected system that C++ does. But it
does usually provide useful hints as to what the main object in any
given interaction is. (ie. distinguishing between controller and
entity classes, in UML terms.) Of course, it's entirely a religious
matter in much the same way as arguing for a clear distinction between
functions and subroutines would be. Just different ways of looking at
it to suit different thought processes.

In article <153fa67.0402021548.6c5e394 at posting.google.com>,
kylotan at hotmail.com (Kylotan) wrote:
I think that's what I meant by violating the abstraction.
Aren't these issues only for the author of the parser?
Why do you want to know what privileges feed has with
one parameter vs. another? Isn't it enough that it works?

Donn Cave, donn at drizzle.com

Not to dampen spirits, but I believe this thread has gone on long
enough and is by this point very OT.

Thanks.

Io vs. Python is a very narrow topic and not fit for a mailing list.
There have been many repetitive Python vs. Ruby threads and nobody
made this complaint. When somebody asks a question about using the
Zope CMF, people don't say "go make a zope-cmf mailing list", they
give a constructive response.

Daniel Ehrenberg

LittleDanEhren at yahoo.com (Daniel Ehrenberg) wrote in message news:<711c7390.0401291301.3f95794 at posting.google.com>...
I think the point is, why on earth would you want to do something like
that? If you want a language you can use to make programs that make
no sense to anyone but the author, Perl should be more than sufficient
for your needs.

alloydflanagan at comcast.net (A. Lloyd Flanagan) wrote in message news:<e838aa6e.0402020730.3d45c9b1 at posting.google.com>...
The point is that implementing your own "for" is something you can't
do in Python very nicely, so it's a proof that Io can achieve
genuinely higher abstraction levels on this part. Implementing
"for" again with a new name probably wouldn't make anyone
happy, but such power opens a set of tricks and idioms to
be used in real code to solve real problems, that wouldn't
be possible in Python without kludgy syntax.

Here's a normal loop:

bar = 0
for x in range(10):
bar += x

Here's the same using a custom loop:

bar = [0]
def temp(x):
bar[0] += x
for_each(range(10), temp)

That is just so damn ugly. I want to be able to define (e.g.)

bar = 0
for_each(x, range(10)):
bar += x

Now tell me which of these two lowermost forms looks
better and makes more sense? For examples that don't
just make aliases of existing syntax, see the
Lisp vs Python thread that was here a few months ago
(sorry, can't remember it's topic name).

BTW, Python can be used to make programs that make
no sense as well. (due to Ulf Bartelt:)

print (lambda Ru,Ro,Iu,Io,IM,Sx,Sy:reduce(lambda x,y:x+y,map(lambda y,
Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,Sy=Sy,L=lambda yc,Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,i=IM,
Sx=Sx,Sy=Sy:reduce(lambda x,y:x+y,map(lambda x,xc=Ru,yc=yc,Ru=Ru,Ro=Ro,
i=i,Sx=Sx,F=lambda xc,yc,x,y,k,f=lambda xc,yc,x,y,k,f:(k<=0)or (x*x+y*y
64+F(Ru+x*(Ro-Ru)/Sx,yc,0,0,i)),range(Sx))):L(Iu+y*(Io-Iu)/Sy),range(Sy
))))(-2.1, 0.7, -1.2, 1.2, 30, 80, 24)

The real question is if the language *allows* a sensible
programmer to write clear, understandable code even in hard
problem domains.

But this is nothing but my humble opinion without actually
knowing anything about Io.. Maybe it isn't that good. I wasn't
really arguing for Io but for better abstractions.

Nobody uses Perl because they like its illegibility, they think (for
some reason) that it's more powerful.
As for the flexibility of Io, there's a big difference between
flexibility and illegibility. Whenever a new, more powerful
programming language comes out, everybody says it's too flexible.
Fortran people were saying that about C, C people were saying it about
C++ and Java, and C++ and Java people are still saying it about
Python. Dynamic typing? That's so error-prone, they say. Flexible
block syntax? Code is "illegible", you say.

Daniel Ehrenberg

C people were saying that about Java?

Look, you like Io better than Python. Fine. You're not going to be
convincing others that you're right by simply repeating it over and over
again. Io and Python cater to different styles; if your personal style
is more in sync with Io, then so be it. But someone whose personal
style is more in sync with Python than Io is simply not going to be
swayed by your largely stylistic arguments.

If you've switch from Python to Io, what will you do with the answers
to these questions? Use them for good or evil? Will you switch back
from Io to Python?
--dang