OpenEuphoria

Re: object(x) rethink

• Posted by Igor Kachan <kinz at peterli?k.r?> Mar 02, 2008
• 762 views

Bill Reed wrote:
 
[snip]

> Sure, integer, atom, and sequences are *objects*, 
> but not all objects are sequences, and 
> not all objects are atoms and 
> not all objects are integers.

Yes, but we are talking just about types of
variables here.

integer i   -- it can be the integer value only
atom a      -- it can be integer and floating
sequence s  -- its elements can be any type, including object type
object x    -- it can be any type at all

> I don't check for "if object(x)" or "if not object(x)"

Ok, but why not to check if variable is type of "object"
or it is not?
 
> If I declare an object as a sequence, and one time it becomes an an integer,
> I get a "type_check failure".  I can assign anything to an object, but I
> can't assign an integer to a sequence.

There is some confusion in "declare an object as a sequence".
Let us say "declare a variable as object" or 
"declare a variable as sequence" etc.

Then, you *can* assign an integer to a sequence using
indexing or slicing.

Try please:

sequence s
integer i i=5
s = {1,2,3,4,{5,5,5,5},6,7}
? s
s[5] = i
? s -- sequence {5,5,5,5} is integer 5 now

 
> }}}
<eucode>
> 
>   object x
> 
>   x = "abc"      -- ok
>   x = -1         -- ok
> 
> But:
> 
>   sequence x
>   
>   x = "abc"       -- ok
>   x = -1          -- type_check error, x is -1
> 
> To fix:
> 
>   object o
>   sequence s
>   integer i
>   atom a
> 
>   o = "abc"
>   o = -1
>   o = 5.3
> 
>   if sequence(o) then
>     s = o
>   elsif integer(o) then
>     i = o
>   elsif atom(o) then
>     a = o
>   end if
> </eucode>
{{{


Ok, but why not to have object(o) is true only
if variable o was declared as object?

Regards,
Igor Kachan
kinz at peterlink.ru