goto, cls, wait commands

[James]

Re: goto, cls, wait commands

On Windows, I use WConio

http://newcenturycomputers.net/projects/wconio.html

It provides other screen functions you might have gotten used to in
QBasic as well.

On unix/cygwin, use curses.

I am not aware of any portable library though.
I used to use cls a lot in my QBasic days. Now I just don't.

[Dan Bishop]

Re: goto, cls, wait commands

Harlin wrote:[color=blue]
> No goto needed. If this makes no sense (which it may not if all[/color]
you've[color=blue]
> been exposed to is BASIC) it wouldn't be a bad idea to Google why you
> should never use a goto statement.[/color]

"GOTO" isn't even needed in QBasic (except for "ON ERROR GOTO").

[jean-michel]

Re: goto, cls, wait commands

"BOOGIEMAN" <BOOGIEMANPN@YA HOO.COM> a écrit dans le message de
news:1ixbe7q69l ob3.1npuu3z54gx 8z.dlg@40tude.n et...[color=blue]
> I've just finished reading Python turtorial for non-programmers
> and I haven't found there anything about some usefull commands I used in
> QBasic. First of all, what's Python command equivalent to QBasic's "goto"[/color]
?[color=blue]
> Secondly, how do I clear screen (cls) from text and other content ?
> And last, how do I put program to wait certain amount of seconds ?
> If I remeber correctly I used to type "Wait 10" and QBasic waits
> 10 seconds before proceeding to next command.[/color]

Hi all,
I saw a lot of comments saying GOTO is not usefull, very bad, and we
should'nt use it because we don't need it.
I think that's true, but only if you *create* programs.
But if the goal is to provide some kind of converter to automatically take
an old application written with an old language (using GOTO), and generating
python code, it would certainly a great help to have this (unclean) feature
in native python.
Best regards
jm

[Nick Craig-Wood]

Re: goto, cls, wait commands

Grant Edwards <grante@visi.co m> wrote:[color=blue]
> I forgot to mention try/except. When I do use goto in C
> programming it's almost always to impliment what would have
> been a try/except block in Python.[/color]

Yes I'd agree with that. No more 'goto out'.

There is this also

for (i = 0; ...)
{
if (something)
goto found;
}
/* do stuff when not found */
found:;

(yes I hate setting flags in loops ;-)

This translates exactly to the for: else: construct

for i in xrange(...):
if something:
break
else:
# do stuff when not found

The last language I saw with this very useful feature was FORTH in
about 1984!

--
Nick Craig-Wood <nick@craig-wood.com> -- http://www.craig-wood.com/nick

[Jeff Shannon]

Re: goto, cls, wait commands

jean-michel wrote:
[color=blue]
> Hi all,
> I saw a lot of comments saying GOTO is not usefull, very bad, and we
> should'nt use it because we don't need it.
> I think that's true, but only if you *create* programs.
> But if the goal is to provide some kind of converter to automatically take
> an old application written with an old language (using GOTO), and generating
> python code, it would certainly a great help to have this (unclean) feature
> in native python.[/color]

But an automatic translator is certain to be imperfect. One can no
more translate mechanically between computer languages than one can
translate mechanically between human languages -- and we've all seen
the fun that can be had by machine-translating from language A ->
language B -> language A, right? What do you think the effect of that
sort of meaning-drift would be on application code?

In other words, any translation from one language to another will
require significant human attention, by someone familiar with both
languages, to ensure that the original meaning is preserved as close
as possible. You're going to have to rewrite chunks of code by hand
no matter what you do; it'd be silly to *not* take that opportunity to
purge things like GOTO.

Jeff Shannon
Technician/Programmer
Credit International

[jean-michel]

Re: goto, cls, wait commands


"Jeff Shannon" <jeff@ccvcorp.c om> a écrit dans le message de
news:110q581gre o8g9e@corp.supe rnews.com...[color=blue]
> jean-michel wrote:
>[color=green]
> > Hi all,
> > I saw a lot of comments saying GOTO is not usefull, very bad, and we
> > should'nt use it because we don't need it.
> > I think that's true, but only if you *create* programs.
> > But if the goal is to provide some kind of converter to automatically[/color][/color]
take[color=blue][color=green]
> > an old application written with an old language (using GOTO), and[/color][/color]
generating[color=blue][color=green]
> > python code, it would certainly a great help to have this (unclean)[/color][/color]
feature[color=blue][color=green]
> > in native python.[/color]
>
> But an automatic translator is certain to be imperfect. One can no
> more translate mechanically between computer languages than one can
> translate mechanically between human languages -- and we've all seen
> the fun that can be had by machine-translating from language A ->
> language B -> language A, right? What do you think the effect of that
> sort of meaning-drift would be on application code?
>
> In other words, any translation from one language to another will
> require significant human attention, by someone familiar with both
> languages, to ensure that the original meaning is preserved as close
> as possible. You're going to have to rewrite chunks of code by hand
> no matter what you do; it'd be silly to *not* take that opportunity to
> purge things like GOTO.
>
> Jeff Shannon
> Technician/Programmer
> Credit International
>[/color]

The automated translations are very commonly used actually in computing
industry. If you want an overview, you can try "legacy migration" in google
for instance (or "as400 automated migration" or anything of that kind).
Translate a computer's language is not the same at all than to translate a
human language. In the first case, you have a good chance to know all the
rules. Even if the work is not perfect, it can offer you a chance to
continue to use a 10000 programs application without having to rewrite all
(several years of work indeed).
The last time I did that, I converted arround 6000 cobol programs in a
couple of months, which is obviously not possible by hand (thanks to python
;-). And it was not possible to remove GOTO, because that would really need
to rewrite manually the programs, that means to entirely redo the
application (probably a 20 human years work !).

Regards,
jm

[Fredrik Lundh]

Re: goto, cls, wait commands

"jean-michel" <nospam@nospam. fr> wrote:
[color=blue]
> And it was not possible to remove GOTO, because that would really need
> to rewrite manually the programs[/color]

really? converting GOTO messes to structured programs has been a solved
problem for many years (you can buy commercial products that does this, and
I don't think they come with programmers in the box)

</F>

[Mike Meyer]

Re: goto, cls, wait commands

Alan Kennedy <alanmk@hotmail .com> writes:[color=blue][color=green]
>> Secondly, how do I clear screen (cls) from text and other content ?[/color]
>
> That depends on
>
> A: What type of display device you're using
> B: What type of interface is being rendered on that display (command
> line, GUI, IDE, etc)
> C: Perhaps what operating system you are using.[/color]

D: Whether or not you have a display device at all. I run Python
scripts from Cron whose sole output functionality is via email. I run
Python scripts as daemons whose sole output functionality is syslog.

"Clear screen" doesn't make sense in thsoe two contexts.

<mike
--
Mike Meyer <mwm@mired.or g> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

[Fredrik Lundh]

Re: goto, cls, wait commands

Mike Meyer wrote:
[color=blue][color=green][color=darkred]
>>> Secondly, how do I clear screen (cls) from text and other content ?[/color]
>>
>> That depends on
>>
>> A: What type of display device you're using
>> B: What type of interface is being rendered on that display (command
>> line, GUI, IDE, etc)
>> C: Perhaps what operating system you are using.[/color]
>
> D: Whether or not you have a display device at all. I run Python
> scripts from Cron whose sole output functionality is via email. I run
> Python scripts as daemons whose sole output functionality is syslog.[/color]

are you the original poster? if so, can you explain why you asked
how to clear the screen if you don't have a screen?

</F>

[Erik Bethke]

Re: goto, cls, wait commands

At least I thought this was funny and cool! -Erik

[Lars]

Re: goto, cls, wait commands

You sir are a troll for sure. QBasic?! When was the last time you did
any programming, 1989? Gave me a laugh though.

Lars