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Python's biggest compromises

I have been reading a book about the evolution of the Basic
programming language. The author states that Basic - particularly
Microsoft's version is full of compromises which crept in along the
language's 30+ year evolution.

What to you think python largest compromises are?

The three that come to my mind are significant whitespace, dynamic
typing, and that it is interpreted - not compiled. These three put
python under fire and cause some large projects to move off python or
relegate it to prototyping.

Whitespace is an esthetic preference that make Andrew Hunt and David
Thomas (of Pragmatic Programmer fame) prefer Ruby. Personally, I love
it - but I can see why some people might not like it (30 years of
braces).

Dynamic typing causes the most fuss. I like Guido's answer to the
question -
"Doesn't dynamic typing cause more errors to creep into the code because you catch them later than compile time?". "No, we use Unit Testing in Zope".


That said, obvious Basic compromised by using things such as "Option
Explicit", thereby allowing both dynamic and more static style
variables. Yahoo groups moved from python to C due to dynamic typing.

Non-compiled - obviously there are times when performance matters more
than other things. Google I believe uses python to prototype (or used)
and then turns to c++ for heavy lifting.

What about immutable strings? I'm not sure I understand Guido's
preference for them.

Anthony
http://xminc.com/anthony
Jul 18 '05 #1
65 6736
On 31 Jul 2003 06:55:52 -0700, an************@ hotmail.com
(Anthony_Barker ) wrote:
I have been reading a book about the evolution of the Basic
programming language. The author states that Basic - particularly
Microsoft's version is full of compromises which crept in along the
language's 30+ year evolution.

What to you think python largest compromises are?

[snip whitespace, dynamic typing, interpreted]

I don't see those as compromises, but mostly as assets.

Significant whitespace (you probably mean significant indentation -
whitespace isn't more or less significant in Python than in other
modern languages) I have only experienced as a boost in readability,
clarity and, most of all, consistence; and there's no possibility of
'brace style wars'.

Dynamic typing vs. static typing has already long ago reached the
status of holy war, so I'll decline to comment.

That python is not (yet) compiled, is mostly a non-issue (and if PyPy
is a success, it won't even be that). If it was just about
performance, then coding the really performance-intensive parts in C
should suffice, apart from kernel hacking and similar . In my
experience, the decision to convert a (successfully functioning)
project from 'a scripting language' to C/C++/Java has always been a
political one, and not really based on technical considerations.

That said, the only large compromise in Python language design I can
detect, is the decision to be quite strictly backwards-compatible
between versions, which is definitely not a bad thing, as long as the
language doesn't go baroque because of it. And Python 3.0 will
hopefully throw out any accumulated cruft.
--Christopher
Jul 18 '05 #2
> What to you think python largest compromises are?

There aren't any.

You want to base significant projects on the highest level, most dynamic
tools available (Python), then use Python as a wrapper to hide static
inflexibilities and inferiorities when descending to lower levels for
whatever (usually spurious) reasons. For example, there is a huge
difference between using wxWindows and wxPython, but the performance
difference between wxWindows and wxPython is insignificant.

Edward
--------------------------------------------------------------------
Edward K. Ream email: ed*******@chart er.net
Leo: Literate Editor with Outlines
Leo: http://webpages.charter.net/edreamleo/front.html
--------------------------------------------------------------------
Jul 18 '05 #3
Anthony_Barker wrote:
(snip)

What to you think python largest compromises are?

The three that come to my mind are significant whitespace, dynamic
typing, and that it is interpreted - not compiled.


IMHO these are not compromises, but features.

Bruno

Jul 18 '05 #4
In article <vi************ @news.supernews .com>, John Roth
<ne********@jhr othjr.com> writes
......High performance isn't Python's target. If PyPy ever gets their act
off the ground, then we will have a shot at a good quality JIT
interpreter. Then watch it fly.
..... doesn't psyco already attempt to do JIT? It certainly doesn't
speed things up that much. If all the variables are known to be of a
specific type then you could expect C like speeds from a good JIT, but
without global analysis it's hard to see how we infer/guarantee python
types.
John Roth


Anthony
http://xminc.com/anthony



--
Robin Becker
Jul 18 '05 #5
"John Roth" <ne********@jhr othjr.com> writes:
[...]
That said, I've come to the conclusion that the editor should take
care of these things for you. If you prefer a brace free notation,
you should be able to tell your editor to present the program to you
that way. If you prefer braces, then it should be able do that for
you as well. That kind of stylistic thing doesn't belong in the
language.
100% agreed: once-and-only-once dictates this. Manually maintaining
both braces and indentation (as in C, with some editors) is Just Plain
Bad for this reason.

In fact, if I didn't have to deal with the braces, I think I'd come
around to the view that the text should have them. Explicit is
better than implicit,
At least in the absence of proper research results, I think this part
of it *is* religious. To some people, it's obvious that whitespace is
better on the eyes. To others, it's obvious that whitespace + braces
is better on the eyes. One group may well be wrong <0.5 wink>.

This argument (that braces are another visual cue which make code
easier to read -- provided that they're automatically maintained in
sync with the indentation), is the only argument against
pure-whitespace that has ever made any sense to me. Irrespective of
whether you pick whitespace or braces as the thing the compiler takes
notice of, though, the optimal solution probably still involves an
editor that supports showing/hiding braces, so the syntax is
(theoretically! ) a non-issue. In practice, editors don't seem to
currently support showing and hiding braces automatically. At least
editors do get you out of most mistakes caused by brace-y languages.

Of course, whitespace *is* still superior because the storage format
doesn't duplicate state -- so people with poor editors can't produce
ambiguous code :-) (remember code can be ambiguous to *people* even if
it isn't to a compiler). OTOH, *Python's* scheme is inferior to a
pure-space-character indentation scheme because off the tab-vs.-space
issue :-(

and there are a few things that the
automatic indentation makes rather difficult in the design area.

[...]

What are those things??
John
Jul 18 '05 #6
In article <89************ *************@p osting.google.c om>,
Anthony_Barker wrote:
I have been reading a book about the evolution of the Basic
programming language. The author states that Basic - particularly
Microsoft's version is full of compromises which crept in along the
language's 30+ year evolution.

What to you think python largest compromises are?

The three that come to my mind are significant whitespace, dynamic
typing, and that it is interpreted - not compiled. These three put
python under fire and cause some large projects to move off python or
relegate it to prototyping.
I don't view any of these as "compromise s". That word suggests that
something was conceded, or that an intermediate position between two
extremes was chosen to appease. I don't think that either sense really
applies to these features.

The three items that you listed are merely design choices. While arguments
over them are continuous, two of the design choices (interpreter, dynamic
typing) are consistent with Python's intended use as a language which
excels at rapid prototyping. The third (white space) is merely a stylistic
choice which is designed to encourage readable programs.

"Compromise s" in language design occur usually when a committee tries to
standardize a language, and each has differing views about how the language
should be used. While this occurs somewhat in Python, other languages
have suffered more mightily from this particular disorder.

Mark
Anthony
http://xminc.com/anthony

Jul 18 '05 #7
It seems to me that a big compromise/feature is that all kinds of
namespaces are usually represented by dictionaries, and that Python
exposes this fact to the programmer. This would seem to limit the
possible optimizations that can easily be performed by a compiler.

BTW, I have only read about Python out of interest, and haven't
actually used it for anything, so I hope my remark isn't ignorant.

Best regards,
Aaron
Jul 18 '05 #8

"Anthony_Barker " <an************ @hotmail.com> wrote in message
news:89******** *************** **@posting.goog le.com...
What to you think python largest compromises are?
A compromise is an in-between position or decision. Example: wife
wants to go to a horse show, husband to an auto race, so they
compromise and go to a horse race.
The three that come to my mind are significant whitespace, dynamic
typing, and that it is interpreted - not compiled.
The first two are end-point positions, not in-between compromises.
The third is a matter of definition and implementation. CPython
compiles to version-dependent but otherwise portable PyCode. PyRex,
Weave, and Psyco all compile to C or machine code.
These three put python under fire
Anything can bo put under fire by anyone who wants to shoot.
and cause some large projects to move off python or
This sort of statement remains an opinion or impression until backed
by evidence.
relegate it to prototyping.
This is one of its intended uses.
Whitespace is an esthetic preference that make Andrew Hunt and David
Thomas (of Pragmatic Programmer fame) prefer Ruby.
Evidence? And I mean evidence that whitespace is *the* reason and not
just a convenient summary of an overall esthetic preference.

In any case, so what? Different strokes for different folks. Do they
also use indentation for human readers? If so, they have assigned
themselves the task of keeping brackets and indents in sync so that
human and machine 'see' the same structure.

I see two good uses for brackets:
1. machine-generated code never intended for human eyes
2. redundancy for transmission error detection by a processor that
compares brackets and indents and raises a flag on mismatches.

A compromise in the area of structure indication would be accepting
either brackets or indents or both.
Yahoo groups moved from python to C due to dynamic typing.
Evidence? Evidence as to what exactly happened (it is not common
knowledge that I know of) and that any such change was a reasoned
technical decision and not politics.

If memory serves me right, Guido has tried a couple of compromises to
slightly limit dynamicity that he could not see much use for and has
backed off at least partly when current users presented use cases that
the change would break.
Non-compiled - obviously there are times when performance matters more than other things. Google I believe uses python to prototype (or used) and then turns to c++ for heavy lifting.


This is a simple matter of economic tradeoff. A week of programmer
time costs roughly the same as, say, a year of pc time. A roaring
success like Google has hundreds (thousands?) of servers around the
world running the same relatively stable code. Faster code means
machines not bought, installed, and maintained. But I imagine that
their main production code is pretty far out on the frequency-of-use
curve.

Terry J. Reedy
Jul 18 '05 #9

Anthony> What to you think python largest compromises are?

Anthony> The three that come to my mind are significant whitespace,
Anthony> dynamic typing, and that it is interpreted - not compiled.
Anthony> These three put python under fire and cause some large projects
Anthony> to move off python or relegate it to prototyping.

Your message is sure to get the pot boiling. I don't think of any of the
above as compromises. They were all design decisions. Considering the
whitespace issue, calling it a compromise suggests that Guido had to cave in
to some outside forces. He couldn't decide between BEGIN/END or {/} as
block delimiters, so he chose significant whitespace. It doesn't make
sense.

Anthony> What about immutable strings? I'm not sure I understand Guido's
Anthony> preference for them.

Performance is one reason. The Python interpreter creates a huge number of
strings at runtime. Knowing exactly how long the string is going to be and
that it will not grow means that a single malloc can be used to allocate the
object header and the storage for the data. If strings were mutable, the
structure of the string object storage would probably be much different and
you'd need at minimum two mallocs per string, one for the object header and
one for the data itself.

Skip
Jul 18 '05 #10

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