What is Expressiveness in a Computer Language

[Andrew McDonagh]

Chris Smith wrote:
> Andrew McDonagh <news at andmc.com> wrote:
>> I haven't read all of this thread, I wonder, is the problem to do with 
>> Class being mistaken for Type? (which is usually the issue)
> 
> Hi Andrew!

Hi Chris

> 
> Not much of this thread has to do with object oriented languages... so 
> the word "class" would be a little out of place.  

Glad to here.

> However, it is true 
> that the word "type" is being used in the dynamically typed sense to 
> include classes from class-based OO languages (at least those that 
> include run-time type features), as well as similar concepts in other 
> languages.  Some of us are asking for, and attempting to find, a formal 
> definition to justify this concept, and are so far not finding it.  
> Others are saying that the definition is somehow implicitly 
> psychological in nature, and therefore not amenable to formal 
> definition... which others (including myself) find rather unacceptable.
> 
> I started out insisting that "type" be used with its correct formal 
> definition, but I'm convinced that was a mistake.  Asking someone to 
> change their entire terminology is unlikely to succeed.  I'm now 
> focusing on just trying to represent the correct formal definition of 
> types in the first place, and make it clear when one or the other 
> meaning is being used.
> 
> Hopefully, that's a fair summary of the thread to date.
> 

Cheers much appreciated!

Andrew