[Pharo-users] Use cases for methods with optional parameters

Esteban A. Maringolo emaringolo at gmail.com
Thu Jan 21 12:04:43 EST 2016


2016-01-21 8:38 GMT-03:00 Henrik Johansen <henrik.s.johansen at veloxit.no>:
>
>> On 20 Jan 2016, at 6:14 , Esteban A. Maringolo <emaringolo at gmail.com> wrote:
>>
>>
>> I would be interested in the use cases and how to deal with
>> "undefined" arguments, will they be nil or other kind of undefined
>> object?

> Perhaps
>
> request: aFile with: anotherThing and: aThirdThing
>         <optionalParameter: anotherThing "default: nil">
>         <optionalParameter: aThirdThing default: defaultThirdThing>
> ->
> request: aFile with: anotherThing
>         ^self request: aFile with: anotherThing and: self defaultThirdThing
> request: aFile and:: aThirdThing
>         ^self request: aFile with: nil and: self aThirdThing
> request: aFile
>         ^self request: aFile with: nil and: self defaultThirdThing


The pragma for the default unless it's a literal object it should be a
message send.

I still have to see a good use case that could justify the use of
that. Because it also involves the message lookup, which AFAIK is
performed by the VM.

Regards,

Esteban A. Maringolo




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