State variables start with an uppercase letter. State variables change in value from state to state.
The value of a state variable on an interval is defined to be its value on the first state. Thus, I=0 means I has initial value zero.
Variables and expressions may be of any of the following types:
integer: |
0, 42, -97, etc. |
Boolean: |
true, false. |
list: |
Lists may be of fixed or variable length. |
string: | String constants are of the form ”abc”. |
float: |
Float constants are of the form $0.123$ or $0.123e+10$. |
lambda: |
This is the type of predicates and functions. |
The function type(X) returns a string representing the type of expression X. For example, type(9)=”integer”.