ezdecs: Some decorators that simplify Python code

Wanna time your code execution easily? Don't wanna spend too much time on input validation? Maybe ezdecs can help!

timer(): Timing execution

By adding @timer before a function, it times the function when the function is called.

from ezdecs import *
@timer
def f():
    print('Hello, world!')
    return 3
print(f())
'''
Example output:
Hello, world!
(3, 6.939999999966417e-05)
'''

noexcept() and cexcept(): Silence exceptions

Using the decorator @noexcept, any exception raised is silenced.

from ezdecs import *
@noexcept
def divide(a,b):
    return a/b
print(divide(9,3)) # 3.0
print(divide(1,0)) # None

If you still wanna know what exception is raised, use @cexcept.

from ezdecs import *
@cexcept
def divide(a,b):
    return a/b
print(divide(9,3)) # (3.0, None)
print(divide(1,0)) # (None, ZeroDivisionError('division by zero'))

tnexcept(): Retry when an exception occurs

By using @tnexcept, the function is repeated until no exception occurs. This is especially useful for input validation and retrying.

For example, instead of writing:

def read_number():
    while 1:
        try:
            result=int(input('Please enter a number: '))
        except:
            pass
        else:
            return result
print(read_number())

All you have to write is:

from ezdecs import *
@tnexcept
def read_number():
    return int(input('Please enter a number: '))
print(read_number())
'''
Example interaction:
Please enter a number: a
Please enter a number: 3.14
Please enter a number: 3
3
'''

The keyword argument handler allows printing custom error messages when encountering invalid input by raising AssertionError.

from ezdecs import *
@tnexcept(handler=print)
def enter_password():
    psw=input('Please enter password: ')
    assert psw=="123","Incorrect password."
enter_password()
print('Correct!')
'''
Example interaction:
Please enter password: a
Incorrect password.
Please enter password: 1234
Incorrect password.
Please enter password: 123
Correct!
'''

For documentation on other decorators see docstring.

Aliases

In order to shorten code, every decorator has a two-character alias:

TM=timer
NE=noexcept
CE=cexcept
BL=block
NL=nolog
TE=tnexcept
RP=repeat
FE=foreach

Problems with recursion

Sometimes using these decorators on recursive functions may cause problems.

The following is an attempt to time a recursive Fibonacci function:

from ezdecs import *
@TM
def f(n):
    if n<2:
        return n
    return f(n-1)+f(n-2)
print(f(5))

Instead of the time and result, a complex nested tuple is returned. That's because after being wrapped by the decorator, f now returns a tuple instead of an integer.

To make it work correctly, the __wrapped__ attribute can be used to retrieve the unwrapped function:

from ezdecs import *
@TM
def f(n):
    if n<2:
        return n
    fw=f.__wrapped__
    return fw(n-1)+fw(n-2)
print(f(5))