user-defined operators

Thomas Lindgren <>
Thu Mar 25 22:19:50 CET 2004


--- "Martin J. Logan" <> wrote:
> I think that the overloading of operators is a nifty
> idea and I can
> think of a few places where it would make my life
> easier. I must state
> in the face of my previous statement that my take on
> operator
> overloading and defining ones own operators is that
> it should not be
> done. Operators should be defined by a central body
> responsible for the
> language syntax and semantics. In this way a modicum
> of consistency in
> the language is ensured. 

However, note that:
- there is a single way to write the new operator:
`op`
- there is a single, fixed precedence
  (one should also define the infix-op to be
non-associative)
- there is a simple semantics (function call)

That avoids most of the problems with extensible
syntax, I think; in particular, there is no need to
know what operators have been defined (or how) to read
the program.

An alternate view is that this is special notation for
a restricted apply. Mangling syntax just a little bit
more:

X `Op` Y -> Op(X,Y).

Best,
Thomas


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