The Random Function

In Darwin, the Rand function begins with a predefined seed and produces a pseudo-random sequence of numbers between $0\ldots 1$.

> Rand();
0.03219977
> Rand();
0.3408
> Rand();
0.7549

If we are to quit, and then restart a Darwin session, we would see that entering

> Rand();
0.03219977
> Rand();
0.3408
> Rand();
0.7549

produces the exact same sequence. This is a nice property which can be exploited when debugging programs that make use of randomization as it allows us to compare successive executions of our program on the same input values.