#8: Various issues with get_class interface
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Reporter: pmichaud | Type: bug
Status: new | Priority: major
Milestone: | Component: core
Version: | Severity: medium
Keywords: | Lang:
Patch: | Platform:
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Description changed by pmichaud:
Old description:
> The get_class opcode doesn't deal well with finding classes
> using an array, and there are other inconsistencies. Here are some:
>
> (1) PDD15 is inconsistent about the mechanisms available to
> identify a class PMC. In various places it says:
>
> - class object, namespace object, key, or string name PMC (isa, line
> 349)
> - classname, namespace, or key PMC (get_attr_keyed, line 655)
> - class object or namespace key (setattribute, line 951)
> - PMC key or namespace object (get_class, line 1034)
> - string PMC, namespace key, class object (new, line 1067)
>
> Notably, nowhere does it allow an array to be used to identify
> a class, although the code does try to allow it (src/oo.c:188)
> and we allow namespace lookups via arrays.
>
> Ideally I think we ought to be able to identify a class by any of
> (a) class object,
> (b) NameSpace PMC,
> (c) Key PMC,
> (d) String PMC.
>
> (2) Looking up a nonexistent class with a String PMC
> produces a null PMC (correct), but looking up a nonexistent
> class with an array produces a "get_string() not implemented in
> class 'ResizableStringArray'" exception:
>
> $ cat x.pir
> .sub main
> $P0 = box 'NoSuchClass'
> $P1 = get_class $P0
> $I1 = isnull $P1
> say $I1
>
> $P0 = split '::', 'NoSuchClass'
> $P1 = get_class $P0
> $I1 = isnull $P1
> say $I1
>
> .end
>
> $ ./parrot x.pir
> 1
> get_string() not implemented in class 'ResizableStringArray'
> current instr.: 'main' pc 15 (x.pir:8)
> $
>
> (2) Even when using an array that does support get_string(),
> we end up looking up the wrong class:
>
> $ cat y.pir
> .sub main
> $P99 = newclass '3'
>
> $P1 = new 'ResizablePMCArray'
> push $P1, 'A'
> push $P1, 'B'
> push $P1, 'C'
> $P0 = get_class $P1 # get class ['A';'B';'C']
> $I0 = isnull $P0
> say $I0
>
> # what class did we get?
> say $P0
> .end
>
> $ ./parrot y.pir
> 0
> 3
> $
>
> Pm
New description:
The get_class opcode doesn't deal well with finding classes
using an array, and there are other inconsistencies. Here are some:
(1) PDD15 is inconsistent about the mechanisms available to
identify a class PMC. In various places it says:
- class object, namespace object, key, or string name PMC (isa, line 349)
- classname, namespace, or key PMC (get_attr_keyed, line 655)
- class object or namespace key (setattribute, line 951)
- PMC key or namespace object (get_class, line 1034)
- string PMC, namespace key, class object (new, line 1067)
Notably, nowhere does it allow an array to be used to identify
a class, although the code does try to allow it (src/oo.c:188)
and we allow namespace lookups via arrays.
Ideally I think we ought to be able to identify a class by any of
(a) class object,
(b) NameSpace PMC,
(c) Key PMC,
(d) String PMC.
(2) Looking up a nonexistent class with a String PMC
produces a null PMC (correct), but looking up a nonexistent
class with an array produces a "get_string() not implemented in
class 'ResizableStringArray'" exception:
{{{
$ cat x.pir
.sub main
$P0 = box 'NoSuchClass'
$P1 = get_class $P0
$I1 = isnull $P1
say $I1
$P0 = split '::', 'NoSuchClass'
$P1 = get_class $P0
$I1 = isnull $P1
say $I1
.end
$ ./parrot x.pir
1
get_string() not implemented in class 'ResizableStringArray'
current instr.: 'main' pc 15 (x.pir:8)
$
}}}
(2) Even when using an array that does support get_string(),
we end up looking up the wrong class:
{{{
$ cat y.pir
.sub main
$P99 = newclass '3'
$P1 = new 'ResizablePMCArray'
push $P1, 'A'
push $P1, 'B'
push $P1, 'C'
$P0 = get_class $P1 # get class ['A';'B';'C']
$I0 = isnull $P0
say $I0
# what class did we get?
say $P0
.end
$ ./parrot y.pir
0
3
$
}}}
Pm
--
--
Ticket URL: <https://trac.parrot.org/parrot/ticket/8#comment:6>
Parrot <https://trac.parrot.org/parrot/>
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