2.3 list reverse() bug?

Arthur ajsiegel at optonline.com
Sun Dec 28 18:36:14 CET 2003


On Sat, 27 Dec 2003 15:26:05 -0600, Bjorn Pettersen
<bjorn.pettersen at comcast.net> wrote:

>[posted and mailed]
>
>Arthur <ajsiegel at optonline.com> wrote in
>news:t0houvc69mtnlrmamh3klgvui8mbf1eu5t at 4ax.com: 
>
>[...]
>
>> But this is also my approach, I guess. Not exactly writing Universe
>> Critical code, I tend to proceed with a light reading of the docs, and
>> learn by having my naive intuitions corrected - as necessary when
>> necessary, by finding something broken.
>
>My late boss approached languages and other problems the same way, and I 
>never could understand how he dealt with what for me would be continous 
>frustration.

There is of course the "take it out on other people" option for
dealing with the frustration.)  Particularly popular option among the
population of bosses, in my experience.  ;)

Or else, better - simply considering it the cost of doing busniess in
the manner in which one chooses to being do business. And consider
oneself net, net ahead of the game - for oneself - when comparing it
to the full cost of doing business in some fundamentally different
way.

> Doing language theory in grad school, while not always the most immediately useful, is a wonderful 
>way to develop passionate ideas about how things ought to be (you should 
>have heard the lunch discussions when Java came out <grin>).

Well of course *my* passionate ideas about language design resolve to
how well that design faciliates *my* chosen way of doing business.
And of course expect everyone to agree.

They don't?

>
>> But there is I feel a valid point implicit in my original question.  
>> 
>> The "I have been using Python 42 years and never imported copy" is a
>> very ambiguous assertion,made time and again.
>
>You're most certainly correct, although I don't believe it was very 
>ambigous when I stated it. If you look at my response to Alex, you'll see 
>that I really do mean that copies are virtually never needed [in the 
>aesthetic, not the Turing complete sense], and if you do use them you're 
>likely to (a) do more work, sometimes potentially _much_ more work, (b) 
>complexificate the algorithm making it harder to visually verify, (c) make 
>it _much_ harder to _prove_ correct, and (d) you're adding another entity 
>that you'll have to keep in memory when you're visualizing the system.

But...

I am going to perform an opertaion on a list or dictionary and need
the alternative to rollback to the pre-operation state.  Restore
"initial".  Why would that be a particularly uncommon or unwholesome
state of affairs, and why isn't leaving a copy behind a practical
approach?

>mission critical subsystem as the 'data-structure' managing this 
>information we wouldn't use anything but a Python code generator, 
>generating over 380KLoc of C++ code, SQL schemas and stored procs, etc.)].

The world is safe from me attempting anything mission critical - for
the time being.

>
>
>I can also categorically say that it's a really bad idea to walk to the 
>middle of a bridge, precariously climb up on the railing, before doing a 
>swan dive towards the dry riverbed several hundred feet below... but it's 
>really fun if you have a bungie-cord attached.

Preferably well attached.

>I haven't encountered any rules that didn't come with their own list of 
>exceptions.

A mutable list, of course.

>
>Sure it is weird to want to think of such trivialities when the code is 
>working, but clean code makes me happy <smile>, and hey, after 20+ years of 
>programming, I'm still excited when I go to work and I still program after 
>I come home...

I compulsively refactor.  Til I have something that seems to me to be
nice.  But nice based on the alternatives as I understand them.  I
also know that there are alternatives I don't (yet) underestand.
Which when I do understand, will generate a new round of refactoring.

This is how I got so smart, by the way ;)

> I sincerely do not grasp mentally however, how some people can "break path" in a new domain guided 
>mainly by their intuition? My intuition definitely doesn't work at that 
>level :-)  If you have any meta-analysis it would be very interesting to 
>contemplate...

Well isn't this something that high level languages, in general - have
made into a not totally unreasonable approach.

Its an expereince to approach things this way - in both the worst and
best sense.

>> Don't we need to pick one meaning for that assertion? Or make the
>> meaning clear, when asserted.
>
>Of course not, this is USENET <wink>. 

Ain't it though.

Art




More information about the Python-list mailing list