Re: What does it take to implement a chat system in Python (Not asking for code just advice before I start my little project)

2013-07-18 Thread Owen Marshall
On 2013-07-18, Michael Torrie wrote: > On 07/18/2013 12:19 PM, Owen Marshall wrote: >> Huh - I (foolishly) didn't realize gmane actually had NNTP, I've always >> used it to search mailing lists. If the list dumped to usenet (much like >> c.l.python) I'd post

Re: What does it take to implement a chat system in Python (Not asking for code just advice before I start my little project)

2013-07-18 Thread Owen Marshall
On 2013-07-18, Grant Edwards wrote: > On 2013-07-18, Serhiy Storchaka wrote: >> 18.07.13 20:04, Terry Reedy ??(): >>> On 7/18/2013 3:29 AM, Aseem Bansal wrote: About reading comp.lang.python can you suggest how to read it and reply? >>> >>> To read this list as a newsgro

Re: UTF-EBCDIC encoding?

2013-07-15 Thread Owen Marshall
On 2013-07-12, Joel Goldstick wrote: > --047d7bdc8be492d67804e154c580 Content-Type: text/plain; charset=UTF-8 > > On Fri, Jul 12, 2013 at 2:11 PM, Wayne Werner > wrote: > >> Is anyone aware of a UTF-EBCDIC[1] decoder? >> >> While Python does have a few EBCDIC dialects in the codecs, it does >> no

Re: Ideal way to separate GUI and logic?

2013-07-15 Thread Owen Marshall
On 2013-07-16, fronag...@gmail.com wrote: > On Tuesday, July 16, 2013 1:06:30 AM UTC+8, asim...@gmail.com wrote: >> fron...@gmail.com wrote: >> >> > So as a general idea, I should at the very least separate the GUI >> > from the program logic by defining the logic as a function, >> > correct? And

Re: Python for IPSA (Power flow analysis)

2013-05-28 Thread Robert Marshall
On Tue, May 28 2013, Debbie wrote: > Hi there, I am new to Python, and wondering if you could help me with > python based coding for the IPSA (Power system analysis software). I > have a electrical distribution network with generators, buses and > loads, on which I am performing the load flow ana

Re: Libroffice PMT equivalent in python

2013-05-04 Thread Michael Marshall
On Saturday, May 4, 2013 11:37:17 PM UTC-4, Michael Marshall wrote: > 4) Partial period payment > > But then if the NPER has a fraction, you may still opt to pay or collect the > payment at the actual time period but the amount you pay is the fraction of > time period time

Re: Libroffice PMT equivalent in python

2013-05-04 Thread Michael Marshall
On Saturday, May 4, 2013 11:37:17 PM UTC-4, Michael Marshall wrote: > On Thursday, April 25, 2013 6:46:01 AM UTC-4, ஆமாச்சு wrote: > If the number of periods have a fractional part such as 10.5 years of 119.25 > months then besides the initial periodic payment, there may be 4 differen

Re: Libroffice PMT equivalent in python

2013-05-04 Thread Michael Marshall
On Thursday, April 25, 2013 6:46:01 AM UTC-4, ஆமாச்சு wrote: > Hi, > > > > Are there equivalent in any Python libraries that could match function > > like PMT in libreoffice? > > > > Refer: https://help.libreoffice.org/Calc/Financial_Functions_Part_Two#PMT > > > > -- > > > > Amachu Th

Re: [pyxl] xlrd 0.8.0 released!

2012-08-18 Thread Brent Marshall
My compliments to John and Chris and to any others who contributed to the new xlsx capability. This is a most welcome development. Thank you. Brent -- http://mail.python.org/mailman/listinfo/python-list

Re: OT: Text editors

2012-07-29 Thread Robert Marshall
On Sun, 29 Jul 2012, python.l...@tim.thechases.com wrote: > On 07/29/12 05:28, Mark Lawrence wrote: >> On 29/07/2012 06:08, Ben Finney wrote: >>> Tim Chase writes: >>> Learn one of Emacs or Vim well, and you won't need to worry >>> about text editors again. >> >> Point taken, snag being I've nev

Re: OT: Code Examples

2011-02-28 Thread Fred Marshall
On 2/28/2011 8:14 AM, n00m wrote: On Feb 28, 6:03 pm, Fred Marshall wrote: The best place for you to start: http://numpy.scipy.org/ Numpy manual: http://www.tramy.us/numpybook.pdf OK Thanks! Fred -- http://mail.python.org/mailman/listinfo/python-list

OT: Code Examples

2011-02-28 Thread Fred Marshall
I'm interested in developing Python-based programs, including an engineering app. ... re-writing from Fortran and C versions. One of the objectives would to be make reasonable use of the available structure (objects, etc.). So, I'd like to read a couple of good, simple scientific-oriented pro

wxPython in the context of Eclipse

2011-02-19 Thread Fred Marshall
I asked earlier: How do I use wxPython or wxGlade in the context of Eclipse? A link to a howto would be great! I guess nobody knows or cares to answer? :-( -- http://mail.python.org/mailman/listinfo/python-list

wxPython in Eclipse?

2011-02-17 Thread Fred Marshall
How do I use wxPython or wxGlade in the context of Eclipse? A link to a howto would be great! Thanks, Fred -- http://mail.python.org/mailman/listinfo/python-list

Re: Python Newbie needs some context

2011-02-16 Thread Fred Marshall
On 2/16/2011 11:45 AM, Grant Edwards wrote: Thanks for the advice! Is it the intent to generate code with wxGlade and then rather "import" that code into an Eclipse project context? Or, should one expect to be able to create hooks (e.g. for Tools) in Eclipse that will do that? If so, how? Tha

Python Newbie needs some context

2011-02-16 Thread Fred Marshall
I can already program in a few languages (but not C++) and, since Python comes to highly recommended, I figured to venture into it. I'm used to using an IDE. So, after some web browsing and reading, I did the following: Installed Python Installed EasyEclipse Installed wxPython Installed wxGlad

Re: your favorite debugging tool?

2009-08-24 Thread Robert Marshall
On 24 Aug 2009, Paul Rubin wrote: > Esmail writes: >> What is your favorite tool to help you debug your >> code? I've been getting along with 'print' statements >> but that is getting old and somewhat cumbersome. > > Beyond print statements, I use pdb a lot. Winpdb (www.winpdb.org) is > even be

Configuring Python for Tcl/Tk in UNIX

2009-06-29 Thread Chris Marshall
My goal is to use Tkinter on a ScientificLinux machine for a GUI I wrote. I installed Python 2.6.2, then built Tcl and Tk 8.5.7 from source. The final step is to configure Python 2.6 to run Tk. When I use the "make" command in the Python 2.6.2 directory, all is well until it tries to built _t

Re: Critique of first python code

2008-02-17 Thread Matthew Marshall
Dan Bishop wrote: > I will say, however, that hasattr(item, '__iter__') isn't a perfect > way of checking whether an object is iterable: Objects that just > define __getitem__ are iterable too (e.g., UserList). Speaking of which, what *is* the best way to check if an object is iterable? I always

sudoku solver in Python ...

2008-01-23 Thread Derek Marshall
This is just for fun, in case someone would be interested and because I haven't had the pleasure of posting anything here in many years ... http://derek.marshall.googlepages.com/pythonsudokusolver Appreciate any feedback anyone who takes the time to have a look would want to give ... Yours

Re: super() doesn't get superclass

2007-09-20 Thread Marshall T. Vandegrift
. Ruby might be a bad example here. Although the Ruby language syntax only supports single inheritance, mixins are implemented as multiple inheritance under the hood. That is, inheriting from a class and including a class as a mixin modifies the sub-/mixing class in exactly the same way. -

Re: strings (dollar.cents) into floats

2007-08-30 Thread Marshall T. Vandegrift
I'm not 100% sure what the best-practices are for representing monetary values in Python, but the `decimal` module is probably a good start. HTH, -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: list index()

2007-08-30 Thread Marshall T. Vandegrift
o provide both as well, but it provides only `index()`. Anyone know the reason for this lack of parallelism? -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: Short, crazy example: list-derived class, with __iadd__

2007-08-29 Thread Marshall T. Vandegrift
gt; print "(w still is:", w > print "after iadd, v: ", v > > # - running it: v starts: [0.0, 0.0] (w is: [1.0, 2.0] which is fine) right now, v is: [1.0, 2.0] as you'd expect (w still is: [1.0, 2.0] after iadd, v: [1.0, 2.0] -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: Gmane's been quiet ...

2007-08-29 Thread Robert Marshall
On Wed, 29 Aug 2007, Steve Holden wrote: > > Lawrence Oluyede wrote: >> Grant Edwards <[EMAIL PROTECTED]> wrote: >>> Posting that were made to mailing lists via gmane? >> >> That, I do not know >> > Given that I have now read a reply to my post-via-gmane on gmane > before seeing the original post

Re: Code design problem

2007-08-29 Thread Marshall T. Vandegrift
LocalApplication and RemoteApplication. HTH!, -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: Class destruction

2007-08-22 Thread Marshall T. Vandegrift
def __enter__(self): return self def __exit__(self, *exc_info): self.close() return False Then the users of this class can freely do any of: f = fout(filename) ... f.close() with fout(filename) as f: ... with closing(fout(filename))

Re: Encryption and hashing

2007-08-17 Thread Marshall T. Vandegrift
of Rijndael as Crypto.Cipher.AES and the 256-bit version of SHA-2 as Crypto.Hash.SHA256. -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: Coroutines and argument tupling

2007-08-16 Thread Marshall T. Vandegrift
ded my ArgPacker is worth it, the complete code for my coroutine decorator follows. -Marshall import inspect import types import functools from itertools import izip __all__ = [ 'coroutine' ] class ArgPacker(object): def __init__(self, function): args, varargs, varkw, default

Re: Coroutines and argument tupling

2007-08-15 Thread Marshall T. Vandegrift
his]) while this: if len(data) == size: _, size = (yield data) data = '' this = file.read(size - len(data)) data = ''.join([data, this]) yield data while True:

Re: Coroutines and argument tupling

2007-08-15 Thread Marshall T. Vandegrift
# => [0, 1] print gen.send(3) # => [2, 3, 4] print gen.send(1) # => [5] The former is just that smidgen nicer, and allows you to continue to make use of argument defaults and varadic arguments if so desired. -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Coroutines and argument tupling

2007-08-15 Thread Marshall T. Vandegrift
create and track a generator when I need a function with generator-like properties. Thanks! -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: encrypting files + filestreams?

2007-08-15 Thread Marshall T. Vandegrift
ntical block in the input stream to result in an identical block in the output stream, which opens the door for all sorts of attacks. Hope this helps! -Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: 2 new comment-like characters in Python to aid development?

2007-03-09 Thread Robert Marshall
On 09 Mar 2007, Matthew Woodcraft wrote: > Bruno Desthuilliers <[EMAIL PROTECTED]> wrote: > Nick Craig-Wood a ecrit : >> I use # FIXME for this purpose or /* FIXME */ in C etc. >> >> I have an emacs macro which shows it up in bright red / yellow >> text so it is easy to see >

Re: 2 new comment-like characters in Python to aid development?

2007-03-09 Thread Robert Marshall
On Fri, 09 Mar 2007, Bruno Desthuilliers wrote: > > Nick Craig-Wood a écrit : >> [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: >>> What if 2 new 'special' comment-like characters were added to >>> Python?: >>> >>> >>> 1. The WIP (Work In Progress) comment: >> >> I use # FIXME for this purpose o

Re: Determining when a file is an Open Office Document

2007-01-19 Thread Robert Marshall
On Fri, 19 Jan 2007, Steven D'Aprano wrote: > On Fri, 19 Jan 2007 12:22:04 +1100, Ben Finney wrote: > >> tubby <[EMAIL PROTECTED]> writes: >> >>> Silly question, but here goes... what's a good way to determine >>> when a file is an Open Office document? I could look at the file >>> extension, bu

Re: Change on file

2006-10-24 Thread Marshall
You could use ctime to see it by the time. MD5 it's a most secure way to a file that CAN'T be modified. If you just want to see if the file has been modified (like to make a cache), use ctime. -- http://mail.python.org/mailman/listinfo/python-list

Re: Computer Language Popularity Trend

2006-09-27 Thread Joe Marshall
Xah Lee wrote: > Computer Language Popularity Trend > > This page gives a visual report of computer languages's popularity, as > indicated by their traffic level in newsgroups. This is not a > comprehensive or fair survey, but does give some indications of > popularity trends. Suggestions: Prov

Re: Secure Postgres access

2006-09-06 Thread Marshall
Can't you limit SSH tunneling access to the IP and/or MAC that you want to access ? It's simplest than any other solution. -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-18 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Chris Smith wrote: > >> Joachim Durchholz <[EMAIL PROTECTED]> wrote: > >> I *think* I understand Marshall here. When you are saying "assignment", > >> you mean assignment to values of attribu

Re: What is a type error?

2006-07-17 Thread Marshall
Chris Smith wrote: > Marshall <[EMAIL PROTECTED]> wrote: > > > If the relations are to > > > be considered opaque, then there's clearly no aliasing going on. > > > > Not certain I understand, but I think I agree. > > My condition, though

Re: What is a type error?

2006-07-17 Thread Marshall
Chris Smith wrote: > Marshall <[EMAIL PROTECTED]> wrote: > > We seem to have slipped back from the hypothetical relation language > > with only assignement back to SQL. > > [...] > I don't see how such a language (limited to assignment of entire > relations) i

Re: What is a type error?

2006-07-17 Thread Joe Marshall
Marshall wrote: > > I am having a hard time with this very broad definition of aliasing. How about this definition: Consider three variables, i, j, and k, and a functional equivalence predicate (EQUIVALENT(i, j) returns true if for every pure function F, F(i) = F(j)). Now suppose i and

Re: What is a type error?

2006-07-17 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Joachim Durchholz wrote: > >> Marshall schrieb: > >>> Good point. Perhaps I should have said "relational algebra + > >>> variables with assignment." It is interesting to consider > >>

Re: What is a type error?

2006-07-17 Thread Marshall
oes. INSERT/DELETE can > > create resp. destroy records, which is what new and delete operators > > would do. > > > > I must really be missing the point. > > I *think* I understand Marshall here. When you are saying "assignment", > you mean assignment to valu

Re: What is a type error?

2006-07-16 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > > > Good point. Perhaps I should have said "relational algebra + > > variables with assignment." It is interesting to consider > > assignment vs. the more restricted update operators: insert, > > update,

Re: What is a type error?

2006-07-16 Thread Marshall
Chris F Clark wrote: > "Marshall" <[EMAIL PROTECTED]> wrote: > > In general, I feel that "records" are not the right conceptual > > level to think about. > > Unfortunately, they are the right level. Actually,the right level > might even be lo

Re: What is a type error?

2006-07-16 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > > But what you descrbe is certainly *not* possible in the > > relational algebra; alas that SQL doesn't hew closer > > to it. Would you agree? > > Yup, SQL (particularly its update semantics) aren't relational

Re: What is a type error?

2006-07-15 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Joachim Durchholz wrote: > >> As I said elsewhere, the record has an identity even though it isn't > >> explicit in SQL. > > > > H. What can this mean? > > > > In general, I feel that &

Re: What is a type error?

2006-07-15 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > >> In some cases, you need an additional level of conceptual indirection - > >> instead of *doing* the updates, you write a function that *describes* them. > > > > But then what do you do with that functio

Re: What is a type error?

2006-07-14 Thread Joe Marshall
Marshall wrote: > Joe Marshall wrote: > > Marshall wrote: > > > > > > Consider the following Java fragment: > > > > > > void foo() { > > > int i = 0; > > > int j = 0; > > > > > > // put any code here you want

Re: What is a type error?

2006-07-14 Thread Marshall
references to mutable data > everywhere. All OO languages are a typical example of that. Now with this, it appears you are agreeing that SQL has an advantage vis-a-vis aliasing compared to OO languages. Yes? If so, we are agreeing on the part I care about, and the specifics of just what we call aliasing are not so important to me. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-14 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > void foo() { > > int i = 0; > > int j = 0; > > j = 1; > > i = 2; > > // check value of j here. It is still 1, no matter what you filled > > // in above. > > // The assi

Re: What is a type error?

2006-07-14 Thread Marshall
Andreas Rossberg wrote: > Marshall wrote: > > > > After all, what are the alternatives? Purely-functional > > languages remove themselves from a large class of > > problems that I consider important: data management. > > Maybe, but I have yet to see how secon

Re: What is a type error?

2006-07-14 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > What about my example of SQL? Mutation, no pointers, no aliasing. > > Yet: useful. > > Sorry, but SQL does have aliasing. Well. I suppose we do not have an agreed upon definition of aliasing, so it is hard to evaluate either

Re: What is a type error?

2006-07-14 Thread Marshall
Chris Smith wrote: > Marshall <[EMAIL PROTECTED]> wrote: > > > What you are asking for is some subset of identity, and I've not yet > > > succeeded in understanding exactly what it is or what its limits are... > > > except that so far, it seems

Re: What is a type error?

2006-07-14 Thread Marshall
George Neuner wrote: > On 13 Jul 2006 08:45:49 -0700, "Marshall" <[EMAIL PROTECTED]> > wrote: > > > >On the other hand, there is no problem domain for which pointers > >are a requirement. I agree they are deucedly convenient, though. > > >

Re: What is a type error?

2006-07-13 Thread Marshall
Chris Smith wrote: > Marshall <[EMAIL PROTECTED]> wrote: > > Chris Smith wrote: > > > Darren New <[EMAIL PROTECTED]> wrote: > > > > Chris Smith wrote: > > > > > Unless I'm missing your point, I disagree with your disagreement. > &

Re: What is a type error?

2006-07-13 Thread Marshall
of its value. I'm not sure what you mean by that. > I also see, though, that the majority (so far, I'd > say all) of the potential uses for which it's worth introducing mutation > into an otherwise mutation-free language allow the possibility of > aliasing, which sorta m

Re: What is a type error?

2006-07-13 Thread Marshall
Joe Marshall wrote: > Marshall wrote: > > > > Consider the following Java fragment: > > > > void foo() { > > int i = 0; > > int j = 0; > > > > // put any code here you want > > > > j = 1; > > i = 2; > > // c

Re: What is a type error?

2006-07-13 Thread Joe Marshall
Marshall wrote: > > Consider the following Java fragment: > > void foo() { > int i = 0; > int j = 0; > > // put any code here you want > > j = 1; > i = 2; > // check value of j here. It is still 1, no matter what you filled in > above. >

Re: What is a type error?

2006-07-13 Thread Marshall
Joe Marshall wrote: > Marshall wrote: > > > > Again, I disagree: it is posible to have mutability without > > pointers/identity/objects. > > I think you are wrong, but before I make a complete ass out of myself, > I have to ask what you mean by `mutability'. (A

Re: What is a type error?

2006-07-13 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Mutability by itself does not imply identity. > > Well, the implication certainly holds from identity to mutability. > The only definition of identity that I found to hold up for all kinds of > references (pointers, shared-mem

Re: What is a type error?

2006-07-13 Thread Joe Marshall
Marshall wrote: > > Again, I disagree: it is posible to have mutability without > pointers/identity/objects. I think you are wrong, but before I make a complete ass out of myself, I have to ask what you mean by `mutability'. (And pointers/identity/objects, for that matter.

Re: What is a type error?

2006-07-13 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Joachim Durchholz wrote: > >> Marshall schrieb: > >>> Joachim Durchholz wrote: > >>>> Marshall schrieb: > >>>>> I can see the lack of a formal model being an issue, but is the >

Re: What is a type error?

2006-07-13 Thread Marshall
Andreas Rossberg wrote: > Marshall wrote: > > > > Okay, sure. But for the problem you describe, both imperativeness > > and the presence of pointers is each necessary but not sufficient; > > it is the two together that causes the problem. So it strikes > >

Re: What is a type error?

2006-07-12 Thread Marshall
David Hopwood wrote: > Marshall wrote: > > > Wouldn't it be possible to do them at compile time? (Although > > this raises decidability issues.) > > It is certainly possible to prove statically that some assertions cannot fail. > > The ESC/Java 2 (http://secure.

Re: What is a type error?

2006-07-12 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Joachim Durchholz wrote: > >> Marshall schrieb: > >>> I can see the lack of a formal model being an issue, but is the > >>> imperative bit really all that much of an obstacle? How hard > >>> i

Re: What is a type error?

2006-07-12 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > I can see the lack of a formal model being an issue, but is the > > imperative bit really all that much of an obstacle? How hard > > is it really to deal with assignment? Or does the issue have > > more to do w

Re: What is a type error?

2006-07-12 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > > I can certainly see how DbC would be useful without subtyping. > > But would there still be a reason to separate preconditions > > from postconditions? I've never been clear on the point > > of differentiati

Re: What is a type error?

2006-07-12 Thread Marshall
mal model being an issue, but is the imperative bit really all that much of an obstacle? How hard is it really to deal with assignment? Or does the issue have more to do with pointers, aliasing, etc.? Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-11 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Now, I'm not fully up to speed on DBC. The contract specifications, > > these are specified statically, but checked dynamically, is that > > right? > > That's how it's done in Eiffel, yes. > > > In

Re: What is a type error?

2006-07-11 Thread Marshall
TAPL? Or ATTPL? Can you cite it a bit more specifically? I want to reread that. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-10 Thread Marshall
Joachim Durchholz wrote: > Marshall schrieb: > > Joachim Durchholz wrote: > >> Chris Smith schrieb: > >>> For example, I wrote that example using variables of type int. If we > >>> were to suppose that we were actually working with variables of type &

Re: What is a type error?

2006-07-10 Thread Marshall
ine down to nothing. > > Don't you have a newsreader that can mark whole threads that you don't want > to read? Sure, or he could just skip over it. Or he could make a simple request, such as "please trim comp.lang.whatever because it's off-topic here." But

Re: What is a type error?

2006-07-10 Thread Marshall
Chris Smith wrote: > Marshall <[EMAIL PROTECTED]> wrote: > > Chris Smith wrote: > > > > > > But this starts to look bad, because we used to have this nice property > > > called encapsulation. To work around that, we'd need to make one of a > >

Re: What is a type error?

2006-07-10 Thread Marshall
also need to add primitives for type > checking, and if the language is stateful, you'll also want primitives > for accessing earlier states (most notably at function entry). Again I'm not entirely clear what this means. Are you talking about pre/post conditions, or are you talking about having the constraint language itself be something other than functional? Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-10 Thread Marshall
sulation is only a hack to get around the lack of a decent declarative constraint language. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-07-09 Thread Marshall
Chris Smith wrote: > > [...] static typing does ... doesn't imply any constraints on the kind > of behavioral property that's being checked; but only on the way that > the check occurs. Nice post. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is Expressiveness in a Computer Language [correction]

2006-06-28 Thread Joe Marshall
Andreas Rossberg wrote: > >~/> ocaml -rectypes > Objective Caml version 3.08.3 > ># let rec blackhole x = blackhole;; >val blackhole : 'b -> 'a as 'a = > > The problem is, though, that almost everything can be typed once you > have unrestricted recursive types (e.g. missing a

Re: What is Expressiveness in a Computer Language

2006-06-28 Thread Joe Marshall
David Hopwood wrote: > Joe Marshall wrote: > > > > The point is that there exists (by construction) programs that can > > never be statically checked. > > I don't think you've shown that. I would like to see a more explicit > construction of a dy

Re: What is Expressiveness in a Computer Language

2006-06-28 Thread Marshall
the data where necessary at the time of > replacement". Translating the data, i.e., re-establishing the > invariants expected by the updated/replaced code, seems much harder > (to me) in the case of self-modifying code. Erlang got this one > right. Pardon my ignorance, but what is

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Joe Marshall
David Hopwood wrote: > Joe Marshall wrote: > > > (defun blackhole (argument) > > (declare (ignore argument)) > > #'blackhole) > > This is typeable in any system with universally quantified types (including > most practical systems with parametric poly

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Joe Marshall
QCD Apprentice wrote: > Joe Marshall wrote: > > Marshall wrote: > >> > >> The real question is, are there some programs that we > >> can't write *at all* in a statically typed language, because > >> they'll *never* be typable? > > >

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Joe Marshall
Marshall wrote: > Joe Marshall wrote: > > Looking back in comp.lang.lisp, I see these examples: > > > > (defun noisy-apply (f arglist) > > (format t "I am now about to apply ~s to ~s" f arglist) > > (apply f arglist)) > > > > (def

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Marshall
Joe Marshall wrote: > Marshall wrote: > > > > Yes, an important question (IMHO the *more* important question > > than the terminology) is what *programs* do we give up if we > > wish to use static typing? I have never been able to pin this > > one down at all

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Marshall
David Hopwood wrote: > Marshall wrote: > > David Hopwood wrote: > >>Marshall wrote: > >> > >>>The real question is, are there some programs that we > >>>can't write *at all* in a statically typed language, because > >>>they'

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Joe Marshall
Marshall wrote: > > Yes, an important question (IMHO the *more* important question > than the terminology) is what *programs* do we give up if we > wish to use static typing? I have never been able to pin this > one down at all. It would depend on the type system, naturally. It

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Marshall
David Hopwood wrote: > Marshall wrote: > > The real question is, are there some programs that we > > can't write *at all* in a statically typed language, because > > they'll *never* be typable? > > In a statically typed language that has a "dynamic&q

Re: What is Expressiveness in a Computer Language

2006-06-27 Thread Marshall
Ketil Malde wrote: > "Marshall" <[EMAIL PROTECTED]> writes: > > > There are also what I call "packaging" issues, such as > > being able to run partly-wrong programs on purpose so > > that one would have the opportunity to do runtime analysis &

Re: What is Expressiveness in a Computer Language

2006-06-26 Thread Marshall
, then some bugs must escape it. I don't think so. Even with a Turing complete type system, a program's runtime behavior is still something different from its static behavior. (This is the other side of the "types are not tags" issue--not only is it the case that there are

Re: What is Expressiveness in a Computer Language

2006-06-26 Thread Marshall
ssible under the circumstances, and writing a separate function > for each narrow type is ridiculous and a maintenance nightmare even if > they can share the bulk of the code. This is the partial function question again, in a different guise. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is a type error?

2006-06-26 Thread Marshall
rgument is zero, but will count on the fact > that the processor will raise an exception one level deeper. This is an implementation artifact, and hence not relevant to our understanding of the issue. Marshall -- http://mail.python.org/mailman/listinfo/python-list

Re: What is Expressiveness in a Computer Language

2006-06-26 Thread Joe Marshall
David Hopwood wrote: > > Joe Marshall wrote: > >> > >>I do this quite often. Sometimes I'll develop `in the debugger'. I'll > >>change some piece of code and run the program until it traps. Then, > >>without exiting the debugger, I&#x

Re: What is Expressiveness in a Computer Language

2006-06-26 Thread Joe Marshall
Marshall wrote: > > I stand corrected: if one is using C and writing self-modifying > code, then one *can* zip one's pants. Static proofs notwithstanding, I'd prefer a dynamic check just prior to this operation. I want my code to be the only self-modifying thing aro

Re: Termination and type systems

2006-06-25 Thread Marshall
David Hopwood wrote: > Marshall wrote: > > David Hopwood wrote: > > > >>A type system that required an annotation on all subprograms that do not > >>provably terminate, OTOH, would not impact expressiveness at all, and would > >>be very useful. > &g

Re: What is Expressiveness in a Computer Language

2006-06-25 Thread Marshall
Chris F Clark wrote: > Chris F Clark (I) wrote: > > > I'm particularly interested if something unsound (and perhaps > > ambiguous) could be called a type system. I definitely consider such > > things type systems. > > "Marshall" <[EMAIL PROTECTED]&

Re: What is Expressiveness in a Computer Language

2006-06-25 Thread Marshall
ithout explicit type annotations > >> with or without type inference > >> > >> Wow. And I don't think that's a complete list, either. > > > > Yup. > > What else? > (Genuinely curious.) I left off a big one: nominal vs. structural Also: h

Re: What is Expressiveness in a Computer Language

2006-06-24 Thread Marshall
alled "suspected." Even if you think something which turns out to be true, we could not say that you "knew" it unless your reasons for your thoughts were valid. I flipped a coin to see who would win the election; it came up "Bush". Therefore I *knew* who was going to w

Re: Saying "latently-typed language" is making a category mistake

2006-06-24 Thread Marshall
Gabriel Dos Reis wrote: > "Marshall" <[EMAIL PROTECTED]> writes: > > | David Hopwood wrote: > | > > | > A type system that required an annotation on all subprograms that do not > | > provably terminate, OTOH, would not impact expressivenes

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