Guard statements should allow you to catch errors via a catch block

[jrose (Jordan Rose)]

This has come up many times before. It would probably be better to pick up one of those threads instead of making a new one.

Guard/Catch

I’d like to propose a guard/catch construct to the language. It would allow code to use throwing functions and handle errors fully, without straying from a happy path. do/catch can be a bit heavy-handed sometimes, and it would be nice to be able to handle throwing functions without committing to all the nesting and ceremony of do/catch. Full proposal, which discusses all the corner cases and alternatives: Looking forward to feedback! Soroush

[Pitch] Guard/Catch

This messages was modified from the original accidentally sent out privately, earlier. FYI this works today in Xcode 9.0 beta 2 playgrounds: class X { init() throws {} func foo() { print( "Things succeeded" ) } } func bar() throws -> X { return try X() } func f() { guard let x1:X = try? X(), let x2:X = try? bar() else { print( "Things failed ") return } x1.foo() x2.foo() } f() // works Most of the examples of this proposed featu…

[Proposal]: Escaping another (unused) scope pyramide with 'guard try catch'

Hello dear Swift community, this proposal might seem like some new syntax sugar, but it also aims to escape the 'do { }' scope from the 'do try catch‘ mechanism while making the existing error handling more powerful. Lets assume we have some sort of network type, which can throw a ton of different errors: struct TCPListener {        init(address: String) throws { /* implement */ }   func accept() throws -> TCPConn { /* implement */ }   /* ... */ } A way of implimentation might look like…

Idea: Extend "guard" to try-statements, with a catch block

Guard statements interact with pattern-matching to ensure that control flow cannot continue unless a pattern is matched. This is a very convenient way to introduce non-optional variables from optional-valued expressions:     // func foo() -> T? ...     guard let x = foo() *else* {         // the compiler does not allow control flow to escape this block     }     // control flow cannot reach here if foo() returned nil Guard statements can be used with the optional form "*try?*" to provide…