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Method clone vs shallowCopy
Last updated at 4:06 pm UTC on 24 April 2017
Levente Uzonyi
Sun, Apr 23, 2017 at 8:57 PM
To: The general-purpose Squeak developers list

On Sun, 23 Apr 2017, Tobias Pape wrote:

On 23.04.2017, at 20:20, commits@source.squeak.org wrote:

uses #shallowCopy instead of #clone

just curious, why?

Both methods are intended to do the same thing. IIRC #shallowCopy is the cross-dialect method for this purpose, while #clone came with Morphic from Self.

They both use primitive 148 to copy the object.

Object >> #clone used to raise an error when the primitive failed, but that might have just been oversight. Now both methods try to fall back to #basicNew(:) and manually copy the fields, which is what #shallowCopy has always been doing.

However, #clone's fallback code now differs from #shallowCopy's, the latter having the newer timestamp, but the former seems to be simpler, because it relies on #copyFrom:.
I can't really tell which fallback code is better, so I'll leave that to someone more knowledgeable.

So I suggest we


P.S.: this was done long ago in Pharo