cs_lec_5

Function mostly have global parent.

Calling every function always

creates a new frame
Binds formal parameters (f&x) to arguments
Execute the body:

    return f(f(x))

Every user-defined function has a parent frame(often global)
The parent of a function is the frame in which it was defined
Every local frame has a parent frame (often global)
The parent of a frame is the parent of the function called

-> You must call the outer(parent) function before you can call or get access to the inner function Anything that was not indented is evaluated in the global frame. Anything indented might be evvaluated in the local frame

Python's job is to figure out frames which to quit and which to keep

There are sometimes that you know one argument early, one argument late. So you want another function nested within the function, that can deal with all the operations of the function after all the arguments are known.

Like for example in the hog game, you may know your own score temporarily, but you may not know the score of your opponent So you can call the outer function first, and call the nested function after you know the score of your opponent.

Scope = all the stuff that you can refer to

HOw to draw an environment diagram: When a function is defined:

Create a function value:

func <name>(<formal parameters>) [parent = <label>]

Is parent is the current frame f1: make_ader func(adder)

When you evaluate a function, you always first evaluate the operator and operand subexpressions 2. Then you must apply the function that are the value of the operator to the argument that are the values of the operands

List : is a container, something that contains other values

add(list1, list2) 
# adding two lists, basically extending/equivalent to list1.extend(list2)

mul(list,number) #adding list number times.

Continuous comparisons(consecutive comparisons), is basically each comparison and everything else. SO for example: $a<b<c<d<e$ evaluates: 1) whether $a<b$ 2) whether $b<c$ 3) whether $c<d$ 4) whether $d<e$

def skip_mul(n):
    if n == 2:
        return 2
    else:
        return n * skip_mul(n - 2)

ERROR IS BASICALLY THAT ONE BASE CASE IS NEGLECTED. This above function will work for even numbers but, for odd numbers, we see that the function will never stop and will recurse forever as it will never meet a base condition. The base condition $n==1$ should be added but is not.