Re: Types, packages & objects : the good old naming conventions question (without religious ware)

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Fri, 30 Oct 2009 22:30:43 -0700 (PDT), Hibou57 (Yannick Duch�ne) wrote:

> A quick add-on, before I forget to write it back here - comments
> welcome on the assertion :
> 
> A program language terms use the dictionary of natural language.
> The natural language has some construct like predicates, adjectives,
> verbs (transitive and intransitives ones), an nouns.
> 
> some has one to one match with the concepts used in a program text :
> predicates and adjectives, verbs (of both forms).

Verb ~ [primitive] operation
Predicate/adjective ~ constraint (e.g. "in"), indexing

> Remain nouns : they may match either object of types, just because the
> natural language does not make this distinction. Indeed, in every day
> life, we are not talking using type and class concepts (neither our
> ancestors does).

No, I think this is wrong. In natural languages there is a distinction
between class and instance. In English (I am not native speaker) it is the
+ uncountable/plural. Other languages have different means.

> Thus, the word � cat �, which may either refer to Douda, my pet cat,
> or to all Cat being (if I can say it this way).

"the cats"

In the natural languages the difference is always blurred because classes
can be objects, e.g. form super classes.

So in the programming languages. The types have operations of they own
though rudimentary in Ada (e.g. T'Class, T'Image). You cannot separate the
name spaces of them and the objects. (The same it true for subprograms.)

Note that generic programming is programming in terms of sets of types. In
Ada it is represented by generics and class-wides. Generic programming is
considered extremely important paradigm. Here you again come to the case
where a type is no more a "proper noun", but just an instance of something
more unique.

Note also that at the formal level type and object are strictly different.
Other programming languages (like C++, Java) have failed here by not
distinguishing T and T'Class. Nevertheless for the programmer, conceptually
cat is-a cat, and he wants to write programs as-if x of T, were of T'Class.
You can never solve this psychological problem. The language shall
differentiate object and type, type and class, class and meta class and so
on ad infinitum. But the programmer will flow up and down this hierarchy of
abstractions choosing his objects and types at each level and names for
them.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de