Shorthand Argument Names $: Only used to refer to formal parameters in closer declarations

Shorthand Argument Names

Swift automatically provides shorthand argument names to inline closures, which can is used to refer to the values of the Closure ' s arguments by the names,, $0 $1 $2 , and so on.

If You use these shorthand argument names within your closure expression, you can omit the closure ' s argument list from it s definition, and the number and type of the shorthand argument names would be the inferred from the expected function type. inThe keyword can also be omitted, because the closure expression was made up entirely of its body:

1. Reversednames = names. Sorted (by: {$ > $ })

Here, and refer to the $0 $1 closure ' s first and second String arguments.

https://docs.swift.org/swift-book/LanguageGuide/Closures.html#ID97

Public Func map<u> (_ Transform: (Value)-U), Result<u, error> {

Return FLATMAP {. Success (Transform)}

}

Refers to Flatmap<u> (_ Transform: (Value), Result<u, error>), Result<u, error> ( Value)

Returns the result of applying ' transform ' to ' Success ' es ' values, or re-wrapping ' Failure ' ' errors '.

Public Func flatmap<u> (_ Transform: (Value), Result<u, error>), Result<u, error> {

Return Analysis (

Ifsuccess:transform,

Iffailure:result<u, Error>.failure)

}

Shorthand Argument Names $: Only used to refer to formal parameters in closer declarations