Summary: The whole closure function is to simplify the language expression form.
First, closure of the simplification
Closure expression syntax have the following general form:
- Reversednames = names.sorted (by: {(s1:string, s2:string)-Bool in
- return s1 > S2
- })
Because The sorting closure is passed as an argument to a method, Swift can infer the types of its parameters and the type Of the value it returns.
Reversednames = names.sorted (by: {S1, s2 in return s1 > s2})
Implicit Returns from Single-expression Closures
Reversednames = names.sorted (by: {S1, s2 in S1 > s2})
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 $, $, $, and so on.
Reversednames = names.sorted (by: {$ > $})
Operator Methods
Reversednames = names.sorted (by: >)
Second, drag-tail transformation
- Func somefunctionthattakesaclosure (Closure: ()-Void) {
- function body goes here
- }
- Here's how to call the This function without using a trailing closure:
- Somefunctionthattakesaclosure (Closure: {
- Closure ' s body goes here
- })
- Here's how to call the This function with a trailing closure instead:
- Somefunctionthattakesaclosure () {
- Trailing closure ' s body goes here
- }
The implementation of closures is outside the list of function parameters;
Streamline again
Reversednames = names.sorted () {$ > $}
Reversednames = names.sorted {$ > $}
Fully removed
- Let strings = Numbers.map {(number), String in
- var number = number
- var output = ""
- Repeat {
- Output = digitnames[number% 10]! + Output
- Number/= 10
- } while number > 0
- Return output
- }
Closures is Reference Types
Whenever assign a function or a closure to a constant or a variable and you are actually setting that constant or variabl E to is a reference to the function or closure.
Escaping Closures
Asynchronous Solutions
Autoclosures
An expression statement
- Customersinline is ["Ewa", "Barry", "Daniella"]
- Func Serve (Customer Customerprovider: @autoclosure (), String) {
- Print ("Now Serving \ (Customerprovider ())!")
- }
- Serve (Customer:customersInLine.remove (at:0))
- Prints "Now Serving ewa!"
Swift Language reviews four-closure