Alvis provides two kinds of the loop statement (see Listing 1). The first statement repeats its contents infinitely. The second one repeats its contents while the guard g is satisfied.

A guard is a Haskell logical expressions placed inside round brackets.

The contents of a loop must be put inside curly brackets and it must contain at least one statement.

The loop statement is a multi-step statement. The first step consists of evaluating the guard (if any) and entering the corresponding loop. Then, a model executes steps inside the loop.

  loop {...}
  loop (g) {...}

Listing 1. Loop statement syntax

x = 10;
y = x;
loop (y > 1) {
  y = y - 1;
  x = x * y;
}

Listing 2. Loop statement example

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