[JoeAltmaier]

Without explicit comments/documentation it is hard to imagine a good example. Its a longstanding issue. Even Lisp has 'equals' and 'equals?' which is an abomination. One looks for identity of object; the other for identity of value (if I understand it right). These kind of things are bug factories.

[deckard1]

Kent Pitman has always been a good read, for the problems of equality in dynamic languages. The typical Ruby or JS programmer stumbles through the day just "getting by", where it comes to comparing objects.

http://www.nhplace.com/kent/PS/EQUAL.html

[icebraining]

I think Python make the difference clear, with == vs "is".

[msbarnett]

Ruby provides object_id for the same purpose. Comparing those for equality provides the "is_" semantics.

[lispm]

Lisp does not have 'equals' and 'equals?'.

Lisp has 'eq', which is for object identity. Lisp has 'equal' which checks for structural equality.

[JoeAltmaier]

and 'equals?'