funcoperators 0.7

Allow infix function notation like (1,2) /dot/ (3,4) for dot((1,2), (3,4) or 1 /frac/ 3 for frac(1,3) and other useful operators to functions.

Always wanted to add custom operators ?

a = (1,2,3) /dot/ (4,5,6) # a = 32

Works for existing functions, like numpy.dot

import numpy
dot = infix(numpy.dot)
a = (1,2,3) /dot/ (4,5,6) # use as an infix
a = dot((1,2,3), (4,5,6)) # still works as a function

Or for custom functions as a decorator

@infix
def f(x,y):
    return x + 2 * y

a = 1 |f| 2 # operator, can use any binary operator like / | * % << >> (beware of ** that is right to left)
a = f(1, 2) # function

dot and cross product

a = (1,2,3) /dot/ (4,5,6) # use as an infix
a = (1,2,3) |dot| (4,5,6) # can use any binary operator like / | * % << >> (beware of ** that is right to left)
r = 2 + (1,2,3) /dot/ (4,5,6) # here "/" has priority over + like in normal python
r = 2 + (1,2,3) *dot* (4,5,6) # for a dot PRODUCT, * seems logical
r = 2 + dot((1,2,3), (4,5,6)) # still works as a function

using '|' for low priority

A + B |dot| C # is parsed as (A + B) |dot| C

fractions

from fractions import Fraction
frac = infix(Fraction)
a = 1 + 1 / 3      # floats are messy...
a = 1 + 1 /frac/ 3 # just replace '/' by '/frac/' to use Fractions
b = 2 * (a + 3) /frac/ (a + 1) # nicer complex expressions

ranges, 2..5 in ruby ?

@infix
def inclusive(a,b):
    return range(a, b+1)

for i in 2 /inclusive/ 5: # could also write |inclusive| or +inclusive+ or %inclusive% or 
    print(i) # 2 3 4 5

for i in inclusive(2, 5): # can still be used as function
    print(i) # 2 3 4 5

pipes : postfix

@postfix
def no_zero(L):
    return [x for x in L if x != 0]

@postfix
def plus_one(L):
    return [x+1 for x in L]

Y = [1,2,7,0,2,0] |no_zero |plus_one # Y == [2,3,8,3]
Y = plus_one(no_zero([1,2,7,0,2,0])) # Y == [2,3,8,3]

pipe factory

def filter_out(x):
    @postfix
    def f(L):
        return [y for y in L if y != x]
    return f

L = [1,2,7,0,2,0] | filter_out(0)

function compose

s = hex(ord('A')) # s = '0x41'

from funcoperators import compose
display = hex /compose/ ord
s = display('A') # s = '0x41'

f = hex *circle* ord # circle = compose

partial syntax

def f(x,y):
    return x + y

from funcoperators import curry
g = f /curry/ 5
y = f(2) # y = 7

from funcoperators import partially
@partially
def f(x,y,z):
    return x + y + z

r = f(1,2,3)
r = f[1](2,3)
r = f[1][2][3]()
# NOT: f[1,2] which will give one argument: a tuple

partiallyauto works only for methods with N fixed positional args

@partiallyauto
def f(x,y,z):
    return x + y + z

r = f(1,2,3)   # r = 6
r = f(1)(2)(3) # r = 6
r = f(1)(2,3)  # r = 6
g = f(1)   # g = a function with two arguments 
r = g(2,3) # r= 6
k = g(2)   # k = a function with one argument

see more examples in the test cases in source code