[squeakdev] ScaledDecimal newFromNumber: 0.0 scale: 0 can't print
Frank Shearar
frank.shearar at gmail.com
Wed Sep 7 18:56:48 UTC 2011
On 7 September 2011 18:24, Nicolas Cellier
<nicolas.cellier.aka.nice at gmail.com> wrote:
> Oops, it was in my image where Integer canUnderstand: #denominator,
> does not seem the case in a base image ?
I can confirm that Integer does not understand #denominator in trunk.
It wouldn't be crazy to just have
Integer denominator [
^ 1.
]
and, if necessary,
Integer numerator [
^ self
]
frank
> Nicolas
>
> 2011/9/7 Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>:
>> And I just checked, and:
>>
>> 1) the senders of isFraction would work equally well if
>> Integer>>isFraction did answer true.
>> This is because they only expect the fraction to answer to
>> #numerator and #denominator, and Integer does that quite well
>> 2) this would fast up mixed Integer/Fraction arithmetic.
>>
>> 3) the senders of asFraction that really expect a Fraction are
>> * Fraction>>adaptToInteger: rcvr andSend: selector
>> * Integer>>adaptToFraction: rcvr andSend: selector
>> But the later would be useless if Integer>>isFraction did answer true.
>> 4) the other senders of #asFraction are in ScaledDecimal and don't
>> care whether the Fraction really is a Fraction or an Integer
>>
>> So it might be time to enforce this peculiarity:
>> Integer>>isFraction
>> "Answer true because every Integer is polymorphic with a Fraction."
>> Integer>>asFraction
>> "See Integer>>#isFraction."
>> ^self
>>
>> Nicolas
>>
>> 2011/9/7 Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>:
>>> OK, I had a chance to open an image and I see I'm responsible for this problem.
>>> Levente changed the printing method, I recognized an already existing
>>> Fraction>>printTruncatedOn:showingDecimalPlaces: and decided to use
>>> it. But this message is not Integer friendly indeed.
>>>
>>> Otherwise, there is no problem if the fraction ivar is an Integer, it
>>> alerady was before, and can continue to be, as long as Integer
>>> instances are polymorphic to Fraction (what they mostly are).
>>> I gonna correct the mess this evening, thanks for reporting!
>>>
>>> Nicolas
>>>
>>>
>>> 2011/9/7 Frank Shearar <frank.shearar at gmail.com>:
>>>> On 7 September 2011 12:32, Nicolas Cellier
>>>> <nicolas.cellier.aka.nice at gmail.com> wrote:
>>>>> Isn't it also the case with (ScaledDecimal newFromNumber: 1.0 scale: 0) ?
>>>>
>>>> It's true for any integralvalued float. Somewhere near the bottom of
>>>> Float >> #asTrueFraction the line
>>>>
>>>> result := signedFraction bitShift: zeroBitsCount negated
>>>>
>>>> returns an Integer.
>>>>
>>>> Presumably (and I'm really just guessing here), we could say
>>>>
>>>> result := Fraction
>>>> numerator: (signedFraction bitShift: zeroBitsCount negated)
>>>> denominator: 1
>>>>
>>>> frank
>>>>
>>>>> 2011/9/7 Frank Shearar <frank.shearar at gmail.com>:
>>>>>> Evaluate the following:
>>>>>>
>>>>>> 0s0 "=> 0s0"
>>>>>> ScaledDecimal newFromNumber: 0 scale: 0 "=> 0s0"
>>>>>>
>>>>>> 0.0s0 "=> 0s0"
>>>>>> ScaledDecimal newFromNumber: 0.0 scale: 0 "=> MNU: SmallInteger
>>>>>> doesn't understand printTruncatedOn:showingDecimalPlaces:"
>>>>>>
>>>>>> The MNU happens because in ScaledDecimal class >> #newFromNumber:scale: we say
>>>>>>
>>>>>> "..." aNumber asFraction "..."
>>>>>>
>>>>>> and when aNumber = 0.0, aNumber asFraction = 0, which is a
>>>>>> SmallInteger and not a Fraction.
>>>>>>
>>>>>> (Recorded as http://bugs.squeak.org/view.php?id=7667)
>>>>>>
>>>>>> frank
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>
>
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