MiniOperators 1.0

Miniature operators for Python

This library makes it almost trivial to add extended operators to the python language, or to transform existing functions into binary operators. For example, one might take the function compose:

def compose(f, g):
    return lambda *args, **kwargs: f(g(*args, **kwargs))

And turn it into an operator, |compose|:

compose = MiniOperator(compose)

Then, the operator can be used as a binary operator [1]:

f = math.sqrt  |compose|  (lambda x: x**2 + 1)
f(0) # 1.0

If one consistently uses this |<name>| notation and parenthesises arguments, no problems should arise [2].

Furthermore, the operator thus created will support overriding through the standard Python convention of __<name>__ and __r<name>__ special methods.

Documentation

The MiniOperator constructor can be called in three ways. MiniOperator(f) creates an operator named f that uses f as its default operation [3]. A name can also be explicitely passed: MiniOperator(name, f), where name is a string, will create an operator named name that uses f as a default operation. Finally, one can create an operator without specifying a default method: MiniOperator(name), where name is a string, will result in an operator that will throw a NotImplementedError when used on most arguments. However, a class will be able to explicitely override __<name>__ or __r<name>__ to support this operator.

Footnotes

[1]

Of course, the initial function must be binary — that is, it must take two arguments — and other obvious restrications apply as well.

[2]

The author would like to suggest using two spaces around the operator and to take special care parenthesizing expressions.

[3]

That is, the name is derived from the __name__ of the passed function. The author suggests not overrelying on this form.