Hi Cle,
> ==========================8X==========================
> (class +Foo)
> # id
>
> (var N 0)
> (var Foos ())
>
> (dm nextId> () (set (var: N) (+ (car (var: N)) 1)))
Just a side-note: While this is correct, you could here take advantage
of the 'inc' operator:
(dm nextId> () (inc (var: N)))
> (dm T ()
> (=: id (pack "Foo#" (nextId> This)))
> (conc (var: Foos) (list (cons (: id) This)))
> )
>
> # (dm foos> () (mapcar '((X) (car X)) (var: Foos))) # *1a*
> # (dm foos> () (mapcar '((X) (car X)) (get '`*Class 'Foos))) # *1b*
> (dm foos> () (mapcar '((X) (cdr X)) (get '`*Class 'Foos))) # *1c*
>
> (dm show> () (prinl "Foo id=" (: id)))
>
>
> (show> (new '(+Foo)))
> (show> (new '(+Foo)))
> (show> (new '(+Foo)))
>
> # (prinl "Foos: " (mapcar '((X) (prinl X)) (foos> '+Foo))) # *2a*
> # (prinl "Foos: " (mapcar '((X) (prinl (type X))) (foos> '+Foo))) # *2b*
> (prinl "Foos: " (mapcar '((X) (show> X)) (foos> '+Foo))) # *2c*
>
>
> (show '+Foo)
> ==========================8X==========================
> ...
> If you execute the code as is, an error will issued at *2c*, that the
> message 'show>' is not understood. But if
>
> * I use *1b* and *2a* instead of *1c* and *2c* the correct id stored in
> the CAR of every element in the assoc list will be printed.
> * I use *1c* and *2b* instead, a type of +Foo will be reported for
> every instance held in the CDR of every association.
> * However, using *1a* instead of *1b* or *1c* will get me nowhere at
> all, despite I think it should have worked :-(
>
> To summarize, *1a* will not deliver, what I expect, but *1b* and *1c*
> seem to return what I want! Asking for the type of every instance held
> in the association list *2b* will answer +Foo correctly. But sending a
> 'show>' to every instance (*2c*) will repsond with "Bad message".
>
> So please enlight me, where is my stumble block? What did I wrong?
The initial error is the 'conc' in the 'T' method. It concatenates the
(id . object) pairs to 'Foos', which is (NIL) in the beginning. So the
list has always NIL as its first element. Then, sending the message
'show>' to that NIL gives an error.
You could take 'push' or 'queue' instead. I use 'queue' here, because
'push' would reverse the order:
(dm T ()
(=: id (pack "Foo#" (nextId> This)))
(queue (var: Foos) (cons (: id) This)) )
But then, of course, 'Foos' has an additional level of nesting. To
access the list, you must use 'car' or 'val':
(dm foos> () (mapcar cdr (val (var: Foos))))
The complete program would then look like:
==========================8X==========================
(class +Foo)
# id
(var N 0)
(var Foos ())
(dm nextId> ()
(inc (var: N)) )
(dm T ()
(=: id (pack "Foo#" (nextId> This)))
(queue (var: Foos) (cons (: id) This)) )
(dm foos> ()
(mapcar cdr (val (var: Foos))) )
(dm show> ()
(prinl "Foo id=" (: id)) )
(show> (new '(+Foo)))
(show> (new '(+Foo)))
(show> (new '(+Foo)))
(prinl "Foos: " (mapcar 'show> (foos> '+Foo)))
(show '+Foo)
==========================8X==========================
Is this what you intended?
Cheers,
- Alex
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