Re: Calling inherited primitive operations in Ada

["Jeffrey R.Carter" <spam.jrcarter.not@spam.acm.org.not>]

On 2022-09-02 08:11, Emmanuel Briot wrote:
> 
> I did point you to the full repository if you prefer an extensive, real-life code sample. This was just an extract showing the gist of the issue.
> 
> One can check the full code and extensive documentation on the design in the github repository.

Yes, I looked at it, and found it over complicated, difficult to understand, and 
not user friendly. There appears to be extensive HTML documentation, but it can 
only be viewed as HTML source in Github, which is not easy to read, so I didn't.

Apparently a user who wants a map has to supply a significant part of what I 
consider the implementation of the map. As such, this may serve as a hidden 
layer to implement a library of data structures, but seems unusable for the 
typical user, for whom using a hashed-map abstraction should be as simple as

function Hash (Key : in Identifier) return Hash_Value;

package Maps is new Lib.Maps
    (Identifier => Identifier, Associated_Value => Associated_Value);

I was not willing to spend more than about 15 minutes trying to understand this, 
so I may be missing something.

> These packages are mostly implementation details. They are used to build high-level packages similar to the Ada containers

This agrees with what I was saying earlier. But even for such a use, simplicity 
and ease of understanding are still the most important aspects of S/W. If 
attaining them involves some code duplication they are worth that price.

>> that pkg Keys serves some actual role in the spec of Maps, then someone wanting
>> to use pkg Maps will need to understand that role, which involves understanding
>> Definite_Elements, which involves understanding pkg Traits, which involves
>> understanding Elements.
> 
> which involves understanding Ada, which involves understanding the compiler, which involves understanding the kernel sources, ...
> How many times have you checked the whole sources of the GNAT runtime to understand how they implemented the Ada containers ?

One understands a pkg by understanding its spec. I find it hard to believe that 
you could actually think that I meant one had to understand the implementation 
as well.

-- 
Jeff Carter
"Apple juice and Darvon is fantastic together."
Play It Again, Sam
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