Thunks syntax/custom operator

[jdesiloniz]

In Scala, thunks are represented by the : => syntax, encapsulating a function that takes no parameters and return a value; to achieve lazy input parameters in functions. It would be nice to use custom operators to create thunks easily, so we can have parameters by name in Swift too.

[jdesiloniz]

To add later:

prefix operator => {}

prefix func =><T>(op: T) -> (() -> T) { return { () -> T in return op } }