OpenEuphoria

Re: object(x) rethink

• Posted by Igor Kachan <kinz at ?eterlink.r?> Mar 04, 2008
• 754 views

Robert Craig wrote:
 
> All types in Euphoria, whether they are
> built-in, like integer(), or user_defined,
> can be used to either declare a variable,
> or test if a value belongs to that type.
> e.g.
> }}}
<eucode>
>     atom a
>     sequence s
>     my_special_type month
> 
>     if atom(9.9) then ...
>     if sequence(x) then ...
>     if my_special_type(11) then ...
> </eucode>
{{{

> 
> So, just for completeness, if you can
> declare something as:
>     object y
> it seems reasonable that you should
> be able to say:
>     if object(z) then ...
> even if that is rather pointless.

Ok, thanks Rob, now I can more precisely express
my additional thoughts about this subject.

Really, sequence(s), atom(a) and integer(i) types
test not only if a *value* belongs to that type, but
also automatically test if a *variable* was declared
with that type.

We can say:
 
   if sequence(s) then -- tests the type of a variable
                       -- on declaration (via value, maybe) 

and

   if sequence(s[i]) then -- tests the value of an element (object)

Same about atom() and integer().

But the object() type doesn't test for *declaration*,
and "tests", so to say, just for *value*, which
(any one) is an object on definition -- all data in
Euphoria are objects, and there is *nothing* to test
at all.

So the obiect() type only lacks (in comparison with
sequence(), atom() and integer() ones) the ability to
test for *declaration* as any *value* is an object
without any testing, just on convention.

Just my $.02, I can live with it as it is and am
ready to leave it alone, but it may be some subject
for some confusion anyway, I think.

[snip]

Regards,
Igor Kachan
kinz at peterlink.ru