Multiple dispatch (Re: [squeak-dev] The Inbox: Kernel-cmm.464.mcz)
frank.shearar at angband.za.org
Sun Jun 20 17:15:03 UTC 2010
On 2010/06/20 18:32, Igor Stasenko wrote:
> Best reference about multiple dispatch can be found in Slate language.
> in short, it is not about varargs but about looking up for a method
> based on a set of behaviors(objects) of message arguments.
Yes, that was Michael's point - that what Brent's talking about is
possibly _not_ multiple dispatch.
> in smalltalk a lookup function takes two arguments:
> F(selector , receiver class)
> with multiple dispatch a lookup function can take any number of arguments:
> F(selector , receiver, arg1 , arg2 .. )
> so, effectively, if method is unary, then you have a single dispatch,
> as in smalltalk, since
> arguments count == 1 (receiver is implicit argument), and if there are
> more than 1 argument,
> then lookup function using properties of every or subset of message
> arguments to find a method.
> On 20 June 2010 17:38, Michael Haupt<mhaupt at gmail.com> wrote:
>> On Sun, Jun 20, 2010 at 4:11 PM, Frank Shearar
>> <frank.shearar at angband.za.org> wrote:
>>>> Since Smalltalk does not support multi-methods, it is essential that the
>>>> caller of a method can pass arguments in multiple formats to the same
>>>> method and have them correctly interpreted by the implementation.
>>> (I assume you are talking about multiple dispatch - method lookup using not
>>> just the receiver but also the types of the parameters to a selector, like
>>> Common Lisp's generic functions?)
>> looks more like varargs to me ...
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