Re: Ada Idioms Progress Preview

[dewar@gnat.com (Robert Dewar)]

Kilgallen@eisner.decus.org.nospam (Larry Kilgallen) wrote in message news:<4V+as+yNIsOy@eisner.encompasserve.org>...
 
> 	MY_VAR : MY_TYPE := MY_FUNC(37);
> 
> is an idiom.  It is strange to someone just learning Ada, but 
> familiar to somewhat who knows Ada.  That is analogous to idioms in 
> English.

And I think that example is *EXACTLY* wrong. This is a straightforward
construct in the Ada language, and is by no stretch of the imagination
an idiom. The analogy with someone just learning english is false. 
Someone just learning English might have trouble understanding:

   the cat sat on the mat

but that does not make it an idiom!

And I think that the proposed catalog of idioms will be far more
useful if it is not simply a rehash of basic Ada rules (as the above
example would be).

In a sense, the example above is simply an instantiation of an axiom,
where the axiom is:

   object_declaration ::=
        defining_identifier_list : [aliased] [constant] 
                                    subtype_indication
                                   [:= expression];

An idiom is more like a theorem, whose meaning must be deduced by
combining axioms, where I am using axiom to mean a basic rule of the
language.

Now if you want to talk about Ada constructs that might be unfamiliar
to someone whose primary knowledge is some other language X, then
that's indeed also useful, but is the solution to a different problem