Re: [perl #61286] [PATCH][PROPOSAL] box complements

2008/12/11 Will Coleda via RT <[email protected]>:
> On Thu Dec 11 01:51:23 2008, fperrad wrote:
>> The new opcode 'box' is limited by its 3 signatures that target Float,
>> Integer & String.
>> I propose the 3 following new opcodes :
>
>>  - true
>>  - false
>
> These can be approximated with:
>
> $P0 = box 1
> $P0 = box 0

No.

On Lua, LuaNumber maps Float & Integer, LuaBoolean maps Boolean.
So, with the current signature of box :
  $P0 = box 1
is equivalent to
  $P0 = new 'LuaNumber'
  set $P0, 1
but I want a LuaBoolean, because I want respect the precise rules of
coercion for arithmetic operations.
The expected behavior with a LuaNumber containing 1 and with a
LuaBoolean containing 1 is not same.

On WMLScript, WmlsInteger maps Integer, WmlsBoolean maps Boolean
So,
  $P0 = box 1
is equivalent to
  $P0 = new 'WmlsInteger'
  set $P0, 1
but I want a WmlsBoolean.


>
> I know you'll end up with an Integer (or, perhaps, a LuaInt) instead of
> a Boolean here. That doesn't work?
>
>>  - undef or nil (less Perlish)
>
> undef and null are two different things in parrot, but we do have an
> opcode for one of them, at least:
>
> $P0 = null
>
>> After some experiments with bytecode translation,
>> in WMLScript (r33655) and in Lua (r33760),
>> it seems obvious that we need them.
>
> Can you explain why?
>

With the opcode 'box', I could rewrite the generation of :
 - ConstantInteger
 - ConstantFloat
 - ConstantString
but not :
 - ConstantBoolean
 - ConstantNil

That's seems not homogene.

>> François.
>
>
> --
> Will "Coke" Coleda
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