In D it is allowed to call a function like this:

| fori(0, 0)

and like this

| fori(0.0)

provided, that `f' is overloaded for example like this:

| void fori(real v){someglobalrealvariable=v;...}
| void fori(int start, int end){for(i=start;i<=end;i++){...}}


However, if the programmer wants to type `f(0.0)' but instead types
`f(0,0)' the catastrophe might be unavoidable:

| Here is a very real example of catastrophic system failure due to a
| simple syntactical problem in a programming language:
|
| The USSR Mars probe, released from the Earth's atmosphere on November
| 27,1971, crash landed on the surface of Mars because its booster rockets
| failed. The failure was due to a single character mistake in the landing
| algorithm, which was written in Fortran. There was a breaking routine
| with a waiting loop of the style "FOR I=1,1000", which didn't perform
| properly, because the comma was replaced with a period, which was
| compiled as "FORI=1.1", variable "FORI" was assigned the value "1.1".
http://www.amadeus-3.com/main_files/oberon2vsCPP.php, [cited 06.02.04]

How does this agree with D's design goal:
| for practical programmers who need to get the job done quickly, reliably

So long.

C learned from the problems of Fortrash.

But I suppose that this kind of problem can crop up in D if the recent suggestion of auto-declared variables (or whatever the term was) is allowed.

These examples are the reason why modern (as opposed to 50s-era) languages require double entry bookkeeping.

The Lone Haranguer wrote:

> But I suppose that this kind of problem can crop up in D if the recent suggestion of auto-declared variables (or whatever the term was) is allowed.

I am with you.

> These examples are the reason why modern (as opposed to 50s-era) languages require double entry bookkeeping.

Double entry bookkeeping? In the example replace the two int's with two real's, then there is no double bookkeeping for a call with two int's, but dmd still does not evoke an error because of the automatic type casting.

Moreover, as D is supposed to be used in programming teams, the two functions might be public and included in a module used by another team member. Have you ever read through a whole interface description? I usually stopped, when I found the function I need. So I would not be even aware of the fact, that the needed function might be overloaded.

If double bookkeeping would be followed to the end, then it would mean for a distributed development team, that every used function from a "foreign" module has to be introduced explicitely into the current scope and that no tool is allowed to help with this introducing.

As you surely know this is not the case with D.

However, to avoid the accidentically call of an overloaded function
containing one number, respectively two numbers in comparable position, D
should
- turn off automatic type casting, or if this is not enough
- require double bookkeeping in the importing module.

I.e. in the example when the overload `fori(int, int)' is declared the
call `fori(0,0)' should generate something like:
| ... : ambiguous overloads for 'fori', introduce overload into scope

when the overload `fori(real, real)' is declared the call `fori(0,0)'
should generate something like:
| ... : ambiguous overloads for 'fori', no implicit type cast

in either case the call `fori(0.0)' should generate something like: | ... : ambiguous overloads for 'fori', introduce overload into scope

So long.

1) no problems here in typing the wrong of two.. its a different place.

2) syntax highlighting the way i do it makes such situations VERY obvious.

namely my numbers are always dark yellow (good to read on white, but not
really pointing out of the screen)
my keytokens ( ({,})+-*/%&| and all those), are all in red (very pointing
out of the screen)..

so

fori(0,0)
and
fori(0.0)

would look entierly different.

and btw, you can do this in c++ as well (and java, i think, too).

"Manfred Nowak" <svv1999@hotmail.com> schrieb im Newsbeitrag news:bvunid$1fqg$1@digitaldaemon.com...
> In D it is allowed to call a function like this:
>
> | fori(0, 0)
>
> and like this
>
> | fori(0.0)
>
> provided, that `f' is overloaded for example like this:
>
> | void fori(real v){someglobalrealvariable=v;...}
> | void fori(int start, int end){for(i=start;i<=end;i++){...}}
>
>
> However, if the programmer wants to type `f(0.0)' but instead types
> `f(0,0)' the catastrophe might be unavoidable:
>
> | Here is a very real example of catastrophic system failure due to a
> | simple syntactical problem in a programming language:
> |
> | The USSR Mars probe, released from the Earth's atmosphere on November
> | 27,1971, crash landed on the surface of Mars because its booster rockets
> | failed. The failure was due to a single character mistake in the landing
> | algorithm, which was written in Fortran. There was a breaking routine
> | with a waiting loop of the style "FOR I=1,1000", which didn't perform
> | properly, because the comma was replaced with a period, which was
> | compiled as "FORI=1.1", variable "FORI" was assigned the value "1.1".
> http://www.amadeus-3.com/main_files/oberon2vsCPP.php, [cited 06.02.04]
>
> How does this agree with D's design goal:
> | for practical programmers who need to get the job done quickly, reliably
>
> So long.
>
>
>
>

davepermen wrote:

> 1) no problems here in typing the wrong of two.. its a different place.

I do not grep what you mean.

> 2) syntax highlighting the way i do it makes such situations VERY obvious.
[...]

That is nice. But syntax highlighting is not part of the language. However, that drives me to the question, whether white space should be made part of the language by introducing a `, ' token as separator for argument lists. Then at least two characters must be wrongly typed.

> and btw, you can do this in c++ as well (and java, i think, too).

That is at least true for c++. But why follow old errors?

So long.

i don't accidentally type the wrong one as the keys are placed in a way to get accessed very differently by my hands. thats what i ment with 1)

2) i know, it's not a language feature. but there is NO reason today to not do your work on a pc, and then send it to the device. and if you work on a pc, you can have at least TextPad to syntax highlight. hey, we're in 2004. :D

btw, i DO understand the problem. i just don't think it is a real problem in real development environments and situations of today anymore.

"Manfred Nowak" <svv1999@hotmail.com> schrieb im Newsbeitrag news:bvvpgb$563$1@digitaldaemon.com...
> davepermen wrote:
>
> > 1) no problems here in typing the wrong of two.. its a different place.
>
> I do not grep what you mean.
>
> > 2) syntax highlighting the way i do it makes such situations VERY obvious.
> [...]
>
> That is nice. But syntax highlighting is not part of the language. However, that drives me to the question, whether white space should be made part of the language by introducing a `, ' token as separator for argument lists. Then at least two characters must be wrongly typed.
>
> > and btw, you can do this in c++ as well (and java, i think, too).
>
> That is at least true for c++. But why follow old errors?
>
> So long.

On Fri, 06 Feb 2004 11:18:54 +0100, davepermen wrote:

[...]
> the keys are placed in a way to get accessed very differently by my hands.
[...]

Upps! Which country do you live in?

> there is NO reason today to not do your work on a pc
[...]

Are you sure?

When have you last time convinced the boss of your 300 computer scientists development team to introduce for the whole team an IDE, text program or syntax highlighting extension of your choice?

I am really not used to work in military, medical, juridical or environments for the caring professions. You might be more experienced in this areas to state such an opinion.

So long.

> Upps! Which country do you live in?
Switzerland. The keys are near, but accessed by different fingers (damn, is
that the right english word? :D).
default qwertz layout.

> Are you sure?
yes. anyone ever NOT used a pc to code in the last years? even for integrated controllers, and all. they upload it trough some COM port to the actual system. everyone uses at least DOS with 'edit', to write the code.

and today, about every workstation for programmers needs (as every
workstation at all:D) some sort of outlook for mailing (hehe), and some sort
of internet access (oooonly for searching for infos about current problems,
of course..).

i know of no programmer who preferes non-syntax-highighted text over syntax-highlighted one. D gives enough possible IDE's and coloured text-editors to chose from.

> When have you last time convinced the boss of your 300 computer scientists development team to introduce for the whole team an IDE, text program or syntax highlighting extension of your choice?
dunno, normally that goes under the hood, without ever noting from the boss.. hey, it's just the boss:D

> I am really not used to work in military, medical, juridical or environments for the caring professions. You might be more experienced in this areas to state such an opinion.
uhm.. uhm?! i'm not at all in such an environment. i just know if there is a more comfortable tool to use, people addopt rapitly. and if it's free, even the boss can't complain.

and we're talking about D here. how much people are yet in D that don't want to change to an IDE because thei're so used to notepad or 'edit' in dos? i know none.

and if we're talking about c++.. vc6 is standard in most places.. never ones / other ones exist, too, of course. but i know of no ide that is in use that doesn't have syntax highlighting.

again, we're in 2004. i have 16million colours to spend on 1310720 pixels. i won't write at any time in black and write. except for this newsgroup mails..

> So long.
that long

>However, if the programmer wants to type `f(0.0)' but instead types
>`f(0,0)' the catastrophe might be unavoidable:
>
>| Here is a very real example of catastrophic system failure due to a
>| simple syntactical problem in a programming language:
>|
>| The USSR Mars probe, released from the Earth's atmosphere on November
>| 27,1971, crash landed on the surface of Mars because its booster rockets
>| failed. The failure was due to a single character mistake in the landing
>| algorithm, which was written in Fortran. There was a breaking routine
>| with a waiting loop of the style "FOR I=1,1000", which didn't perform
>| properly, because the comma was replaced with a period, which was
>| compiled as "FORI=1.1", variable "FORI" was assigned the value "1.1".

1)  that's what code reviews are for,  if the app is safety or "mission" critical then it should be thoroughly review.

2) Unit testing would probably have found it also

even a very strict language like Ada will not prevent all "human" mistakes

On Fri, 6 Feb 2004 18:35:52 +0100, davepermen <davepermen@hotmail.com> wrote:
> i know of no programmer who preferes non-syntax-highighted text over syntax-highlighted one.

You do now. :-)

I find it distracting and ugly, especially when bright colors are used.  I do use fonts (and sizes thereof) in which commas and periods are easily distinguishable, though.

-Scott