[squeak-dev] [Pharo-dev] Message>>#= & Message>>#hash

Marcus Denker marcus.denker at inria.fr
Tue Nov 20 09:16:47 UTC 2018



> On 20 Nov 2018, at 01:16, Eliot Miranda <eliot.miranda at gmail.com> wrote:
> 
> Hi David,
> 
> On Mon, Nov 19, 2018 at 9:52 AM David T. Lewis <lewis at mail.msen.com <mailto:lewis at mail.msen.com>> wrote:
> On Mon, Nov 19, 2018 at 09:32:17AM -0800, Eliot Miranda wrote:
> > Hi All,
> > 
> >     In VisualWorks Message implements #= & #hash naturally; two messages
> > whose selectors and arguments are #= are also equal.  But in Cuis, Squeak
> > and Pharo Message inherits #= and #hash from Object, i.e. uses identity
> > comparison.  This is, to say the least, annoying.  Any objections to
> > implementing comparing in Message to match VisualWorks?
> > 
> 
> That sounds like an obviously good thing to do :-)
> 
> Is the lookupClass instance variable relevant for comparisons? I am
> guessing not, since we already have #analogousCodeTo: for that type of
> comparison.
> 
> For me it is relevant.  Two messages with different lookupClasses, e.g. one with nil and one with a specific class, represent different messages, one a normal send one a super send.  So my changes in waiting include lookupClass in both hash and =.  I don't think it makes much difference, but the incompatibility with VisualWorks, while regrettable, feels correct to me.
> 

To me this looks like a good change, yes.

	Marcus

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