built in operators: measure-currency

measure-currency:
    description:
        measure-currency sp
        measures the "currency" used by a superposition
        Ie, the sum of the coefficients of all the kets in the given superposition
        If the superposition is "clean" then measure-currency is the same as the how-many operator

    examples:
        measure-currency (3|a> + 1.2|b> + 0.1|c>)
            |number: 4.3>

    see also:
        how-many, show-many, clean