error handling - swift, optional unwrapping, reversing if condition -

error handling - swift, optional unwrapping, reversing if condition -

let's have function returns optional. nil if error , value if success:

func foo() -> bar? { ... }

i can utilize next code work function:

let fooresultopt = foo() if allow fooresult = fooresultopt { // go on right operations here } else { // handle error }

however there few problems approach non-trivial code:

error handling performed in end , it's easy miss something. it's much better, when error handling code follows function call.

correct operations code indented 1 level. if have function call, have indent 1 more time.

with c 1 write this:

bar *fooresult = foo(); if (fooresult == null) { // handle error , homecoming } // go on right operations here

i found 2 ways accomplish similar code style swift, don't either.

let fooresultopt = foo() if fooresult == nil { // handle error , homecoming } // utilize fooresultopt! here allow fooresult = fooresultopt! // or define variable

if i'll write "!" everywhere, looks bad taste. introduce variable, doesn't either. ideally see following:

if !let fooresult = foo() { // handle error , homecoming } // fooresult has bar type , can used in top level

did miss in specification or there way write looking swift code?

your assumptions correct—there isn't "negated if-let" syntax in swift.

i suspect 1 reason might grammar integrity. throughout swift (and commonly in other c-inspired languages), if have statement can bind local symbols (i.e. name new variables , give them values) , can have block body (e.g. if, while, for), bindings scoped said block. letting block statement bind symbols enclosing scope instead inconsistent.

it's still reasonable thing think about, though — i'd recommend filing bug , seeing apple it.

swift error-handling optional