Operator overloading revisited

P T Withington ptw at pobox.com
Wed Jul 1 09:58:52 PDT 2009

On 2009-07-01, at 03:48EDT, Christian Plesner Hansen wrote:

> Methods live on objects and their prototypes.

Only if you co-opt the word "method" to mean that.  I would claim this  
is just shorthand for "instance method".  There is also "class method"  
or "static method".  There are other definitions (see below).

On 2009-07-01, at 10:23EDT, Brendan Eich wrote:

> How much sweeter could this be sugared?
> function "+"(a :Point, b :Number) {
>   return new Point(a.x + b, a.y + b);
> }
> function "+"(a :Number, b :Point) {
>   return new Point(a + b.x, a + b.y);
> }
> function "+"(a :Point, b :Point) {
>   return new Point(a.x + b.x, a.y + b.y);
> }
> (Here the quoted operator names imply multimethod addition, where  
> previously I used |generic function| to Tucker's enthusiastic +∞).


Not to suggest paint, but I think the syntactic sugar of Dylan has a  
nice color:

`a + b`  is sugar for `\+(a, b)`

`\+` is a generic function (of 2 arguments) to which you can add  
"methods".  Methods are just syntactic sugar for specifying the  
branches of a dispatch algorithm (http://portal.acm.org/citation.cfm?id=236338.236343 
).  [That is since `+` is not a legal identifier, you have to escape  
it to use it as an identifier, to name a generic function.]

If "method" has to be used uniquely in Javascript as the word that  
means a computation attached to an instance, maybe we just need a new  
word to mean "dispatch element of a generic function".  I would have  
said "generic function method", which (ambiguously) gets abbreviated  
to "method", and may be the source of objection?

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