"Richard A. O'Keefe" <ok at cs.otago.ac.nz> wrote:

> (4) The complaints by several people that writing x := x + y just isn't
>     a big deal miss the point.  The point is to have notational
>     uniformity between updating an object (which is the value of x)
>     that can increment itself and updating a variable (whose value
>     is immutable and cannot increment itself).
> 

This is a huge difference, and the two operations shouldn't be made to
look the same.  Updating a value is bread and butter in most languages. 
Rebinding a variable to a new value is a very big deal, and is even
outlawed in many languages.

Besides, won't a programmer like to know which operation is happening?

	x := <whatever>.
	y := x.
	y mutateByAdding: 3

Then I want x to change no matter what <whatever> is.  If I do:

	x := <whatever>.
	y := x.
	y := y + 3.

Then I *don't* want x to change, no matter what <whatever> is.   How
often will you not care which interpretation is used?  If you have any
statements like the "y := x" above, then getting the wrong
interpretation will probably mess up your program.

-Lex