Can't use ForeignObject>>#copy to copy objects that have no 'copy' member

[stefreschke]

list := Polyglot eval: 'ruby' string: '[]'.
copy := list copy

This throws an Error (Foreign object does not understand "copy"), because ForeignObject>>#copy calls ForeignObject>>#'_dispatch:arguments:ifFail:' with "copy" as member, which the ruby list does not have.

[fniephaus]

Thanks for the report! What's the expected behavior? If Ruby lists don't implement copy, a debugger seems reasonable. Or would you want the object to behave like a Smalltalk object (actually performing a shallow copy)?

[stefreschke]

Well, since ForeignObject offers a copy and deepCopy method respectively, it would be optimal to receive adequate (shallow) copies or deep copies of these ForeignObjects.

If there is no way to copy/deepCopy those objects language independently and the methods are only meant as a short cut to invoking "copy" members, the debugger is fine. It then reduces to raising awareness that the programmer himself needs to worry about how to copy these objects (e.g. by finding the correct members).

[fniephaus]

BTW: Ruby lists can be copied with #dup or #clone.