Re: Eiffel and Java + Ada dispatching

[Robb Nebbe <nebbe@iam.unibe.ch>]

On overloading:

you need to keep in mind that a language is a tool. People become very frusterated
with tools that interfere with doing work rather than help, unless they can
rationalize this in terms of saftey or something. Overloading is the language
getting out of your way so you can concentrate on what is really important.

Think of it as separation of concerns. When you are writing software it is better
to concentrate on finding meaningful names rather than "Did I already use that
somewhere?" I have better things to do than manually resolving overloading.

You are correct in saying that there is no semantic difference between
unique names and overloading. However, just because there is no semantic
difference don't suppose that it doesn't play a critical role in how the language
is defined. 

By the way, consider what Eiffel does. It determines which routine is to be called
based on the name of the routine and the type of one of the parameters. The only
difference with Ada is that Ada uses all the parameters. There is no semantic
difference between determining statically or dynamically which method is invoked.
When Eiffel compilers optimize away dispatching all they are really doing is
static overload resolution. 

Don Harrison wrote:
> 
> Robert Dewar writes:
> 
> :... In particular, overloading plays quite
> :an important role with respect to generic instantiation, and is much
> :more than syntactic sugar in Ada.
> 
> You appear to be referring to RM 12.3(14) under Generic Instantiation, Static
> Semantics which says
> 
>   "The interpretation of each construct within a generic declaration or body
>    is determined using the overloading rules ...".
> 
> Maybe I don't understand what this means but it's not clear how this is any
> different from other uses of overloading (in which there is no semantic
> difference from using unique procedure names). If you can provide an example
> showing there is such a difference, I'll believe you.