Prepitch: Character integer literals

[Chris_Lattner3 (Chris Lattner)]

@allevato

So, if we want to pursue this, the consistent way would be to define a new compiler-known protocol, ExpressibleByASCIICodeUnitLiteral, have UInt8 conform to it, and then update the handling of string literals in the compiler to make them type-check correctly, detecting errors at compile-time instead of runtime

This can be made to work, but the logical endpoint of this is that UInt16 would allow code points that fit into a UTF16 size and UInt32 would allow any code point. Is that desirable? I could see how this could be confusing to some:

let x : Int = "f"

One nice thing about the C approach with single quotes is that it makes it clear what is going on, and it would allow defining a new default type for:

 let x = 'x'

which would clearly be Character.

-Chris