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Switch-Case in pure Python

Project description

switchcase implements a simple Switch-Case construct in Pure Python.

Under the hood, the switch function works by simply returning a length-1 list containing a matching function. The entire implementation is 3 lines long:

from operator import eq
def switch(value, comp=eq):
    return [lambda match: comp(match, value)]

Basic Usage

>>> from switchcase import switch
>>> def func(x):
...     for case in switch(x):
...         if case(0):
...             print("x was 0")
...             break
...         if case(1):
...             print("x was 1")
...             break
...     else:
...         print("x was unmatched")
>>> func(0)
"x was 0"
>>> func(1)
"x was 1"
>>> func(2)
"x was unmatched"

Custom Comparisons

By default, switch uses operator.eq to compare the value passed to switch and the values subsequently passed to case. You can override this behavior by passing a comparator function to switch as a second argument.

>>> import re
>>> from switchcase import switch
>>> def f(x):
...     out = []
...     for case in switch(x, comp=re.match):
...         if case("foo_bar"):
...             out.append(0)
...             break
...         if case("foo_.*"):
...             out.append(1)
...         if case(".*_bar"):
...             out.append(2)
...         return out
>>> f("foo_bar")
>>> f("foo_notbar")
>>> f("notfoo_bar")
>>> f("foo____bar")
[1, 2]

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