[swift-dev] Using Objective C class in Swift (open source, Linux)

[Joe Groff]

> On Feb 1, 2016, at 4:46 AM, Труб Илья via swift-dev <swift-dev at swift.org> wrote:
> 
> 
> 
> Everybody knows, that is very simple in XCode, there are many tutorials, for example, 
> http://stackoverflow.com/questions/24002369/how-to-call-objective-c-from-swift
> or
> https://github.com/gergelyorosz/swift-objective-c-mixed-project
> 
> But I read in some sources, that that is impossible in Linux (I have Ubuntu 15) for open source swift compiler. Is it true?
> I mean, for example, such simple code:
> file C.h
> #import <Foundation/NSObject.h>
> @interface C : NSObject
> @property (copy) NSString *cu;
> @end
> 
> file C.m
> #import "C.h"
> @implementation C
> 
>   - (id)init { self = [super init]; self.cu = @"Hello world!"; return self; }
> 
>   - (void)setCu:(NSString *)str { self.cu = str; }
> 
>    @end
> 
> file s.swift
> let c = C()
> print(c.cu)
> 
> I can easily compile C.m in such way:
> clang++ C.m -c -I<paths to headers on my host> -fblocks -o C.o
> 
> But how to import C.h to s.swift in order to avoid:
> 
> s.swift:2:9: error: use of unresolved identifier 'C'
> let c = C()
> We have not bridge-technology as in XCode.
> 
> In what way open source swift compiler could be developed to implement such feature?

Swift only implements ObjC interop with Apple's ObjC runtime on iOS/tvOS/watchOS and 64-bit Mac. It could be ported to other runtimes in theory, but someone would have to do that work.

-Joe