loop

#loop

##Syntax A loopStatement is:

loop statementsAndDeclarations end loop

##Description A loop statement causes the statements (and declarations) in it to be repeatedly executed. This continues until terminated by one of its enclosed exit statements (or by an enclosed return or result statement).

##Example Output on separate lines: Happy, Happy, Happy, etc.

    loop
        put "Happy"
    end loop

##Example Read words up to the word Stop.

    var word : string
    loop
        get word
        exit when word = "Stop"
    end loop

##Details A loop statement can contain more than one exit, or none at all (in which case it is an infinite loop). When the exit when is at the beginning of the loop, the loop works like Pascal's do while; when at the end, the loop works like Pascal's repeat until.

Just preceding the statements and declarations, you are allowed to write an "invariant clause" of the form:

This clause is equivalent to: assert trueFalseExpn.

    invariant trueFalseExpn