[M3devel] "target specific pragmas"?

[Tony Hosking]

I don't want to add fuel to the fire, but ....

On Feb 14, 2008, at 1:34 PM, hendrik at topoi.pooq.com wrote:

> On Thu, Feb 14, 2008 at 12:09:40PM +1100, Darko wrote:
>> M3 is the antithesis in the sense that it takes the opposite  
>> approach.
>> C has few protections, M3 has many. M3 does examine what was wrong
>> with C and other languages and fix them and it did a good job. The M3
>> design team made an explicit goal to look at features from other
>> languages and take the best. The fact that M3 works so well is the
>> proof.
>>
>> Some of the things you raise, like braces
>
> I'm assuming this is the use of '{' and '}' instead of 'BEGIN' and
> 'END'.
>
> Natural languages evolve in the direction of having the mopst-oftern
> used words be the shortest.  This makes it possible to say muc in less
> space and time.  And it makes it easier to get an overview of a
> program whose physical size is becoming inconvenient.  Just haveing
> the code be readable and seeing enough of its context makes
> debugging easier.
>
>> or stack allocations of
>> objects are just features of C++ with no justification.
>
> Stack allocation of objects is not such a big issue in C++.  But it  
> can
> be a big issue in those programs where split-second real-time
> interaction is an issue.  Yes, I know this is the traditional argument
> against garbage collection, and that it is usually based on FUD rather
> than reality.  But I have recently been in close contact with a
> programmer of video games, and for some of them the fraction-of-a- 
> second
> pauses are a real problem.  He really *wants* to write his games in a
> decent language, and he knows that C is not one.
>
> But every time he avoids heap allocation he delays the pause.  If
> he can delay it enough, it's a win.  If he can delay it altogether,
> that's success.

There are true "real-time" garbage collectors in development and  
deployment now that avoid applications from seeing pauses.
Modula-3 is getting better in this respect, but it is still not quite  
there.  But, fortunately, Modula-3 provides UNTRACED objects/ 
references which *never* themselves cause GC.  In fact, for the  
current CM3 implementation it would be possible to have a real-time  
thread run and manipulate only UNTRACED references and never ever see  
a GC pause -- it would keep running even while other threads are  
caught up by GC!

>> Can you show
>> that typing less characters is important? You say M3 is less
>> convenient, but what is less convenient, less typing or less bugs?
>
>   This is a false dichotomy.  You may well be able to reduce typing
> *and* reduce bugs, just by making code more readable.

I don't find M3 to be unreadable at all.  In fact, I find it to be  
very readable.

> I doubt that typing "PROC" instead of "PROCEDURE", for example, is
> likely to introdice bugs.  Not typing '{' instead of "BEGIN".  Using
> special characters and lower-case keywords is likely to reduce bugs,
> because it's less likely that one will be misread for another.
>
>> Do
>> you spend most of your time typing or thinking when you write code?
>
> I think before I write code.  I don't stop thinking when I start
> writing code, and I like to record my thoughts as I think.  The less
> typing I need to do, the better I can get visual feedback on my
> thoughts while thinking.  Sometimes the typing gets so tedious I get
> bored and lose interest.  Then extra typing causes extra bugs.

Who types?  I use an editor that completes and indents Modula-3 code  
with exactly the same number of keystrokes as I use when programming  
in C.

>>
>> Should language include every feature anyone can think of?
>
> No.
>
>> How is
>> excluding unimportant features 'arbitrary'? Each feature must be
>> weighed to avoid unnecessary complexity and size, which have a direct
>> impact on compiler maintainability and language usability. Language
>> bloat is a real problem. I doubt that anyone understands the full
>> semantics of C++.
>>
>> You say that C has 'won', but in what sense? More people use it?
>> Language design is not American Idol, it's not a question of who has
>> the most votes.
>
> Enough people use it that it has become a fixture in the programming
> world.  If you want to reuse existing code instead of always writing
> new, you are pretty much forced into some kind of interfacing  
> between C
> and a reasonable language.  The convenience of this interfacing can  
> well
> determine whether the reasonable language is feasible for a specific
> application.

And CM3 does this very well -- that does not mean we should permeate  
the Modula-3 space with C'isms.

>
> -- hendrik