[Python-Dev] Infix operators (original) (raw)

Fredrik Johansson fredrik.johansson at gmail.com
Fri Jul 25 02:02:41 CEST 2008

On Fri, Jul 25, 2008 at 12:06 AM, Scott Dial <scott+python-dev at scottdial.com> wrote:

Perhaps I'm nobody, but I think this would be ridiculous. Matrices are not native objects to the language. There is no type(matrix). The notion of what makes a Python object a matrix is a convention and to have built-in operators dedicated to such objects makes no sense. There are multiple ways to stuff matrices into Python. Please submit a PEP for a type(matrix) first. Until a matrix is a first-order object in Python, there is no logic to making operators for them.

Though I would personally find a matrix multiplication operator useful, I have to agree with this.

Anyway, it is easy to define pseudo-operators in Python; just create an Operator class and implement its mul and rmul methods appropriately (there are recipes for this around somewhere). Then you can define various custom multiplication operators with syntax like this:

A matrixmul B A dot B A cross B A elementwise B

Some other fun possibilities:

A +concat+ B A /solve/ B A left_inverse (-1) A right_inverse (-1) x tetrate y n |choose| k

Fredrik

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