Re: Why is Ada considered "too specialized" for scientific use

[Warren <ve3wwg@gmail.com>]

Nasser M. Abbasi expounded in news:hpddc6$csh$1@speranza.aioe.org:

>> I am making big use of these containers in the rewrite of
>> my basic interpreter project. >
> 
> I looked at the Ada 2005 LRM, Containers.Vectors for example, and And
> I have small question
> 
> http://www.adaic.org/standards/05rm/html/RM-A-18-2.html
> 
> Given this below
> 
> function Element (Container : Vector;
>                   Index     : Index_Type)
>    return Element_Type;
> 
> 
> Then to get the element at index 5, one needs to write something like 
> Element(V,5).
> 
> Is there a way to redefine this so one need to only write V(5) ?

You could use V.Element(5), but that doesn't really
shorten the notation.

You could declare an internal function for that purpose, though
there are probably better solutions:

procedure My_Proc(args...) is

   package P is new Ada.Containers.Vector(...);
   V : P.Vector;

   Function XV(X : Index_Type) returns Element_Type is
   begin
      return V.Element(X);
   end;
begin
   ... := XV(5);

Note however (as I found out, snickers), you can't use the
V.Element() notation when the input value is a cursor. That
kept tripping me up until I clued in-- the cursor specifies
both the container and position internally. So you must use
Element(Csr) form of the call instead, for cursor values.

> because If I have large equations, it is more clear to write V(i) than
> Element(V,i) everywhere? Did you find this "longer" syntax an issue
> for you? 

Not really, because when you deal with several containers (Maps mostly
in my case), I tend to spell out the full package heirarchy anyway 
for clarity and to avoid hiding caused by "use".

One thing I did do however, was create a SimpMap package that
took care of all of the compare function definitions for me.
I got real tired of redeclaring equality functions for every
new integer/modular type involved.

> I have not used Containers before. But the list of functions looks 
> impressive.
> 
> ps. is your interpreter project somewhere on the net to look at?
> 
> thanks,
> --Nasser

My Ada rewrite is still in the early stages, so it is not up on
SourceForge yet. If you want to experiment with the C version,
or look at the documentation, you can visit:

https://sourceforge.net/projects/bdbbasic

or for language and other documentation:

https://sourceforge.net/apps/mediawiki/bdbbasic/index.php?title=Main_Page

But if you email me directly, I can also send you the tar-balled 
Ada version of the project. You'll see a lot of container examples 
in it, which might be useful.

Warren