To do a visualization type:
    ch3-04.out < <input_string>

input1:

x = 3 * 2
y = x + 1
3 * y

input2:
3 * (2 + 4)
x = 24
y = x + 1
3 * y
2 + x + y

input3:
foo = 12 * 2
foo / 5
thisisareallylongvariable = 42
thisisareallylongvariable * 22
