CENG 2002 PL Concepts - Functional Programming - Lecture 1

closures.py

b = 8

def do_something(a):  
   global b
   b += 1
   return a + b

  
print(do_something(40))   
print("b is now", b)
print(do_something(40))
print(do_something(40))


import time 

def make_counter():
   print("IN make_counter")
   cnt = 0
   time.sleep(2)
   def count():
      nonlocal cnt
      print("IN count")
      cnt += 1
      print("COUNT=", cnt)
   print("RETURNING FROM make_counter")      
   return count
   
   
c1 = make_counter()
c2 = make_counter()
c3 = make_counter()   


c1()
c1()
c1()
c2()
c3()
c2()
c1()



def make_counter2(start_val=0, incr=1):
   cnt = start_val

   def count():
      message = "COUNT="
      nonlocal cnt
      print("IN count")
      cnt += incr
      print(message, cnt)
      message = "NEW MESG="
         
   return count

c4 = make_counter2()  # 1, 2, 3, 4, ... 
c5 = make_counter2(100,5)  # 105, 110, 115, 120, ...
c6 = make_counter2(20) # 21, 22, 23, 24, ...





   
   

fib_memoization.py

def memoize(f):
    memo = {}
    def helper(x):
        if x not in memo:            
            memo[x] = f(x)
        return memo[x]
    return helper
    

def fib(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n-1) + fib(n-2)

# fib = memoize(fib)
# print(fib(40))

lecture.ipynb