Day 9: Tuesday, Feb 4th, 2014

0. Read the following two links: what is WSGI, Wikipedia on WSGI; skim a stack overflow question and the WSGI PEP
1. Quiz: answer some questions
2. What is StackOverflow anyway? Hey, and what’s a PEP?
3. WSGI in practice; separation of concerns. (Presentation.)
4. Thinkin’ ‘bout functions.

Fun with functions and callables

try1: what does the following code print, if placed in a file and executed?

def f(n):
    return 3 * n

def g():
    return f

value = g()
print value(5)

try2: what does the following code print, if placed in a file and executed?

def g(n):
    def f():
        return 8*n

    return f

value = g(5)
print value()

try3: what does the following code print, if placed in a file and executed?

class Klassy(object):
    def __init__(self, n):
        self.n = n

    def val(self):
        return 4*self.n

k = Klassy(5)
print k.val()

try4: what does the following code print, if placed in a file and executed?

class Klassy(object):
    def __init__(self, n):
        self.n = n

    def val(self):
        def g(m):
            return 3 * self.n + m

        return g

k = Klassy(4)

fn = k.val()
print fn(3)

try5: what does the following code print, if placed in a file and executed?

class Klassy(object):
    def __init__(self, n):
        self.n = n

    def val(self):
        def g(m):
            return 3 * self.n + m

        return g

k = Klassy(4)

fn = k.val()

k.n = 8
print fn(4)

try6: what does the following code print, if placed in a file and executed?

class Klassy(object):
    def __init__(self, n):
        self.n = n

    def __call__(self):
        return 5*self.n

k = Klassy(5)
print k()

try7: what does the following code print, if placed in a file and executed?

def some_function(other_fn, value):
    value = value*5

    value2 = other_fn(value)

    return value2

def f(n):
    return n + 1

def g(m):
    return m - 1

print some_function(g, 5)
print some_function(f, 4)

try8: what does the following code print, if placed in a file and executed?

global_value = 6

def some_function(other_fn, value):
    value = value*global_value

    value2 = other_fn(value)

    return value2

def f(n):
    return n + 1

def g(m):
    return m - 1

print some_function(g, 5)
print some_function(f, 4)

global_value = 2

print some_function(g, 5)
print some_function(f, 4)