Discussion: Introducing new operators for matrix computation - general approach?

[Andrew Henshaw]

Gregory Lielens  wrote:
>John Lull wrote:
...snip...

>> I'm don't think this is quite fair.  You could just as easily write: 
>>  b = rDiv(X, y) >> if you simply had an appropriate rDiv() function.
..snip..
>Indeed, but it is the old choice between functional/operator notation...
>For example, the second expression, b = (X'*X)\(X'*y), would be in
>functional notation 
>something like b=rDiv(Mul(X.T(),X),Mul(X.T(),y))
>This is ok, but imho far more error prone than operator notation,
>because 
>- all linear algebra textbooks present expressions with operator
>notation
>- the operator notation is more natural to almost everybody when dealing
>with arithmetic
>
I wonder if some of these problems could be approached in a more general
manner.  What if Python could support the definition of operators in the
same manner as functions? If that were the case then something like:

opr rDiv(X, y):

would define a new operator function that would work like:

b = X rDiv y

The big advantage would be that special purpose grammars could be easily
imported.  The core language could be kept as simple as possible, but still
be extensible in a  way that matters to a lot of people.

I suspect that whitespace would be required around these new 'operators',
although many people already do that with regular operators.  Also, I'm not
sure how you'd specify an operator that wasn't valid as a function name, but
I can think of possibilities.

-- 
Andy Henshaw