Object identity

[Paul]

You can use the `eq` operator for checking for object identity with any AnyRef object in Scala.

Wouldn’t it be more elegant to rename this to `is`. This way, you could write more readable code

    if (a is b) ...

What do you think?

Regards, Paul

[Rex Kerr]

This eq a really bad idea.

"A cow is a mammal."

Seems like "is" has as much to do with types than with individual identity, and certainly isn't a synonym for referential equality.

Besides which, introducing a new reserved word, which happens to be an extremely common word, for aesthetic reasons is a good way to cause a huge headache for people who used the word to mean something else.  There will be many such headaches.

  --Rex

[etorreborre]

Yes, claiming a new "is" reserved word would be problematic for some people :-).

E.

[Paul]

This sounds reasonable.

[Eric Kolotyluk]

In some languages the keyword 'isa' is used - presumably in Scala you could use 'is' and 'isa' as two different keywords - but I am not advocating that.

I also find 'eq' a little annoying as for me 'it does not read well' in code. On the other hand, I would not be offended if there was some symbolic operator (chicken track) for 'these two objects are the same object, that is they are identical' such as '≡' so long as there were an easy way to insert it from a standard keyboard in the appropriate IDE. I think

   if a ≡ b then . . . else . . .

is perfectly clear (to me) and most readable, where 'eq' is a synonym for '≡'

We have a wonderful world of UTF-8 that we should use better, as there are just some mathematical symbols that are very clear and well understood, just so long as no-one gets carried away, for example using '⊨' instead of 'true' and '⊭' instead of false.

Cheers, Eric

[Josh Suereth]

a hasSameMemoryLocationAs b

Or with a pointless DSL:

a has same memory location as b

Verbosity FTW.

And an implementation for the confused:

object location

object same

implciit def betterEquals[A](a: A) = new {

  def has(x: same.type) = new {

    def memory(x: location.type) = new {

      def as[B](b: B) = a eq b

[Jonas Bonér]

LOL. Taken.

--
Jonas Bonér