The pseudo-code that will be used in this course is RASCAL (Richard's Alternative Condensed Algorithmic Language.) Some of its features are:
Types are inferred.
Operators on reals are +,-,*,/ and exponentiation.
Operators on integers are +,-,* and exponentiation.
The / operator on two integers is mathematically correct, i.e. causes a conversion to reals. To get an integer a conversion is needed.
The assignment operator is <-.
Comparison operators are the mathematical ones including = .
There's an intechange operator, viz. <-> .
Indentation induces a bracketing, e.g.
if logical expression statements
Sets and set operations are included.
Comments are inclosed in {...} and are executed. If true execution continues; otherwise execution halts. In particular,
{preconditions: must be true at the beginning of a loop or subprogram}
{postconditions: must be true at the end of a loop or subprogram}
{loop invariants: must be true every time execution reaches their position.}
Parallelism: is indicated by [...;....;...] with [ causing a fork and ] a join.
Randomness: a random{...} function returns an element with uniform probability.
Nondeterminism:
The choice[..;..;..] function returns an arbitrary element or statement.
The success function terminates the program with a true.
The fail function terminates the program with a false.