You're focusing on the wrong part :) Which element of your code has a type
of "NSGraphicsContext"? It's cocoaCTX! The compiler error is suggesting you
do one of these:

cocoaCTX?.graphicsPort
cocoaCTX!.graphicsPort


On Wed, Jul 1, 2015 at 6:28 PM, Rick Mann <rm...@latencyzero.com> wrote:

> I'm trying to do this:
>
> class
> Context
> {
>     init()
>         throws
>     {
>         let cocoaCTX = NSGraphicsContext.currentContext()
>         guard let sysCTX = cocoaCTX.graphicsPort as! CGContextRef else {
> throw Errors.InvalidContext }
>         CGContext = sysCTX;
>     }
>
>     var CGContext : CGContextRef
> }
>
>
> But I'm getting
>
> error: value of optional type 'NSGraphicsContext?' not unwrapped; did you
> mean to use '!' or '?'?
>                 guard let sysCTX = cocoaCTX.graphicsPort as! CGContextRef
> else { throw Errors.InvalidContext }
>                                    ^
>                                            !
> In the typical if-let, you don't add the ?. If I do add the ?, I get:
>
> error: '_??' is not convertible to '_??'
>                 guard let sysCTX = cocoaCTX.graphicsPort? as! CGContextRef
> else { throw Errors.InvalidContext }
>                                    ~~~~~~~~~~~~~~~~~~~~~^
>
> Errors is an enum I created in a different file.
>
> I always seem to trip up on the conditional optional unwrapping. Not sure
> what I'm doing wrong here. Help is much appreciated. Thanks!
>
> --
> Rick Mann
> rm...@latencyzero.com
>
>
>
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