How to initialize Decimal?

[Morten_Bek_Ditlevsen]

Perhaps you’re right. I remember this discussion from when the ‘ExpressibleByXxx’ were called XxxConvertible:

Allow FloatLiteralType in FloatLiteralConvertible to be aliased to String

Like Dmitri said, a String is not a particularly efficient intermediate representation. For common machine numeric types, we want it to be straightforward for the compiler to constant-fold literals down to constants in the resulting binary. For floating-point literals, I think we could achieve this by changing the protocol to "deconstruct" the literal value into integer significand and exponent, something like this: // A type that can be initialized from a decimal literal such as // `1.1` or `…

And this:

Is there a need for a Decimal type?

Decimal libraries would be great. However, there are a few different kinds of decimal that are interesting—currency tends to have different domain-specific behavior from general floating-point decimal, for instance. One thing I'd like to see us eventually fix at the language level is the low-level protocol for decimal literals. The current behavior of `FloatLiteralConvertible` is to pass the floating-point value down as a binary floating-point Double, making it unsuitable for use by decimal libr…