[Python-Dev] Re: [Fwd: Discussion: Introducing new operators formatrix computation]

[Gordon McMillan]

Huaiyu Zhu wrote:

> The whole field of linear algebra is built on eight statements,
> two of them can be derived from the other.  You can't even define
> all the concepts like upper or lower case, white space, tab,
> symbol, character and number and identifier and concatenation and
> so on in just eight statements, let alone to state all the rules
> of text processing.

You claimed elsewhere that these arguments were quoted out 
of context, yet you bring them up again. So let's nail this, 
alright?

Text processing doesn't use any new operators. It reuses 
some arithmetic operators. Everything else is done with 
methods or functions.  If that's what a linear algebra extension 
used, there would be nothing to discuss.

Or you could take something like the regex route:
 pyLinearAlgebra.evaluate(r'(X`*X)\(X`*y)', X=X, y=y)
... and there would be nothing to discuss.

But you want new operators, and that's a can of worms. They 
need to be spelled sensibly and in a way that doesn't conflict 
with current Python punctuation / operators. They need 
precedence rules built into the grammar. If the precedence 
rules aren't right, the operators are damn near useless, 
because it will take so many parens to get the right result, 
you might as well be using one of the above techniques.
 
> The issue arises because one generalization is more familiar to
> one group of people but the other is to other people.  And people
> tend to regard what they are not familiar with as "specific
> domain".

Python isn't a matrix manipulation language. Like any 
language that does in-fix, adding operators is a tricky 
business and affects everybody, whether they know it or not.

- Gordon