Numerical

Returns a function that takes an optional arg and uses it as the operand or injects a argument from some other source (e.g., HTML element, query string).

When called, the returned function returns the operand if it matches the type, otherwise returns an Error.

• IsInteger = operand => (arg => Either<Error, Integer)
• IsPrecisionNumber = operand => (decimalPlaces = 0) => (arg => Either<Error, PrecisionNumber)
• IsRealNumber = operand => (arg => Either<Error, RealNumber)