operators.cm

# Every operator and punctuation mark, with each two-character form written
# beside the one-character form it could be confused with.
#
# ignore CM0409 in file
# ignore CM0410 in file
# A catalog names each result so a reader can see what the operator gives back.
# Nothing goes on to read them, and reading them would say nothing more.

shared model Operators

    function Arithmetic(integer a, integer b)
        let sum = a + b;
        let difference = a - b;
        let product = a * b;
        let quotient = a / b;
        let remainder = a % b;
        let negated = -a;
    end function

    function Comparison(integer a, integer b)
        # Each pair puts the longer operator next to its shorter form, which is
        # where a mistake in longest-match scanning would show up first.
        let lessOrEqual = a <= b;
        let less = a < b;

        let greaterOrEqual = a >= b;
        let greater = a > b;

        let equal = a == b;
        let notEqual = a != b;
    end function

    function Assignment(integer a)
        integer target;
        target = a;
    end function

    function Logical(boolean p, boolean q)
        let both = p and q;
        let either = p or q;
        let negation = not p;
    end function

    function TypeOperators(Model value)
        let isString = value is string;
        let asString = value as string;
    end function

    function Punctuation(integer[] items, string text)
        # Parentheses, brackets, braces, comma, semicolon, and dot.
        integer[] literal = {1, 2, 3};
        let indexed = items[0];
        let member = text.Count;

        # A call is punctuation too, but this one yields nothing, so there is no
        # result to give a name to.
        Operators.Arithmetic(1, 2);
    end function

    function OptionalAndLambda()
        # The question mark is a type suffix; a lambda's body follows "yield".
        integer? maybe;
        integer delegate(integer, integer) add = (a, b) yield a + b;
        let recovered = maybe.Or(0);
    end function

    function CaseLabels(integer code)
        # The colon appears only at the end of a case label.
        switch code
            case 1:
                Console.WriteLine("one");
            default:
                Console.WriteLine("other");
        end switch
    end function

    function Fractions()
        # The pipe separates a fraction's numerator and denominator.
        constant fraction ratio = 3|4;
    end function

end model