with Explanations

Evolution of a Python programmer.py

#Newbie programmer
# Exp: -> first exercise in recursion
def factorial(x):
    if x == 0:
        return 1
    else:
        return x * factorial(x - 1)
print factorial(6)


#First year programmer, studied Pascal
# Exp: -> You declare vars at the top of program/function in pascal (also you use i:= i+1 type syntax to avoid confusing with equality)
#      -> Notice iterative solution
def factorial(x):
    result = 1
    i = 2
    while i <= x:
        result = result * i
        i = i + 1
    return result
print factorial(6)


#First year programmer, studied C
# Exp: -> Note the braces 
# >>> from __future__ import braces
#  File "<stdin>", line 1
#  SyntaxError: not a chance
# -> C assignment syntax
def fact(x): #{
    result = i = 1;
    while (i <= x): #{
        result *= i;
        i += 1;
    #}
    return result;
#}
print(fact(6))


#First year programmer, SICP
#Exp: -> @<thing> is a decorator - applies a function to a function (pretty dope stuff)
#     -> seems like the programmer just learned about tail calls in a Lisp class (Hence SICP reference - Structure and Interpretation of Computer Programs - great book)
@tailcall
def fact(x, acc=1):
    if (x > 1): return (fact((x - 1), (acc * x)))
    else:       return acc
print(fact(6))


#First year programmer, Python
#Exp: -> xrange is generator - meaning it "emits/yields" a value when asked to instead of storing all the items(like list) - slightly more optimized but overkill
def Factorial(x):
    res = 1
    for i in xrange(2, x + 1):
        res *= i
    return res
print Factorial(6)


#Lazy Python programmer
# Exp: -> nicer syntax - x>1 and x*fact(x-1) only evaluates true when x>1 (slightly silly but works)
#      -> also helped by the fact that 1 = True in python unlike Ruby
def fact(x):
    return x > 1 and x * fact(x - 1) or 1
print fact(6)


#Lazier Python programmer
# Exp: -> why name a function when you can use anonymous functions? (lambda)
f = lambda x: x and x * f(x - 1) or 1
print f(6)


#Python expert programmer
#Exp: -> slightly fancier library functions, overkill here but extremely useful for a lot of projects
import operator as op
import functional as f
fact = lambda x: f.foldl(op.mul, 1, xrange(2, x + 1))
print fact(6)


#Python hacker
#Exp: -> Python allows operator overloading via __sub__ and __mul__ methods, a lot of abuse of those things here
import sys
@tailcall
def fact(x, acc=1):
    if x: return fact(x.__sub__(1), acc.__mul__(x))
    return acc
sys.stdout.write(str(fact(6)) + '\n')


#EXPERT PROGRAMMER
#Exp: Using the optimized C library instead
import c_math
fact = c_math.fact
print fact(6)


#ENGLISH EXPERT PROGRAMMER
# Exp: making fun of english/british people and their insistence on proper grammar - even in programming
import c_maths
fact = c_maths.fact
print fact(6)


#Web designer
#Exp -> copy pasted, too much comment, n00b
def factorial(x):
    #-------------------------------------------------
    #--- Code snippet from The Math Vault          ---
    #--- Calculate factorial (C) Arthur Smith 1999 ---
    #-------------------------------------------------
    result = str(1)
    i = 1 #Thanks Adam
    while i <= x:
        #result = result * i  #It's faster to use *=
        #result = str(result * result + i)
           #result = int(result *= i) #??????
        result str(int(result) * i)
        #result = int(str(result) * i)
        i = i + 1
    return result
print factorial(6)


#Unix programmer
#Exp: -> writes a shell script (most likely in Perl), puts in system path and calls that instead
import os
def fact(x):
    os.system('factorial ' + str(x))
fact(6)


#Windows programmer
#Exp:-> Uses way too many windows system calls
NULL = None
def CalculateAndPrintFactorialEx(dwNumber,
                                 hOutputDevice,
                                 lpLparam,
                                 lpWparam,
                                 lpsscSecurity,
                                 *dwReserved):
    if lpsscSecurity != NULL:
        return NULL #Not implemented
    dwResult = dwCounter = 1
    while dwCounter <= dwNumber:
        dwResult *= dwCounter
        dwCounter += 1
    hOutputDevice.write(str(dwResult))
    hOutputDevice.write('\n')
    return 1
import sys
CalculateAndPrintFactorialEx(6, sys.stdout, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL)


#Enterprise programmer
# Exp:-> too many classes, even when the problem is really solvable in two lines
def new(cls, *args, **kwargs):
    return cls(*args, **kwargs)

class Number(object):
    pass

class IntegralNumber(int, Number):
    def toInt(self):
        return new (int, self)

class InternalBase(object):
    def __init__(self, base):
        self.base = base.toInt()

    def getBase(self):
        return new (IntegralNumber, self.base)

class MathematicsSystem(object):
    def __init__(self, ibase):
        Abstract

    @classmethod
    def getInstance(cls, ibase):
        try:
            cls.__instance
        except AttributeError:
            cls.__instance = new (cls, ibase)
        return cls.__instance

class StandardMathematicsSystem(MathematicsSystem):
    def __init__(self, ibase):
        if ibase.getBase() != new (IntegralNumber, 2):
            raise NotImplementedError
        self.base = ibase.getBase()

    def calculateFactorial(self, target):
        result = new (IntegralNumber, 1)
        i = new (IntegralNumber, 2)
        while i <= target:
            result = result * i
            i = i + new (IntegralNumber, 1)
        return result

print StandardMathematicsSystem.getInstance(new (InternalBase, new (IntegralNumber, 2))).calculateFactorial(new (IntegralNumber, 6))