參考：
https://stackoverflow.com/questions/32758811/catching-nsexception-in-swift
https://github.com/jonbrooks/ObjCTryCatch/blob/master/ObjCTryCatch/ObjCTryCatch.m

#import <UIKit/UIKit.h>

//! Project version number for ObjCTryCatch.
FOUNDATION_EXPORT double ObjCTryCatchVersionNumber;

//! Project version string for ObjCTryCatch.
FOUNDATION_EXPORT const unsigned char ObjCTryCatchVersionString[];

@interface ObjCTry <__covariant T>: NSObject

/**
 * wraps `block` in an Objective C try block, catching any exceptions
 * and returning them in the user info of the returned error.  This will
 * import into swift as a throwing function that throws the error. 
 */
+ (BOOL)doTry:(void(^)())block error:(NSError **)err;

/**
 * Same as above, but used for blocks that produce an Objective C object.
 */
+ (T)doTryObj:(T(^)())block error:(NSError **)err;

@end

#import <Foundation/Foundation.h>
#import "ObjCTryCatch.h"

@implementation ObjCTry

+ (BOOL)doTry:(void(^)())block error:(NSError **)err {
    @try {
        block();
        return YES;
    }
    @catch (NSException *exception) {
        *err = [NSError errorWithDomain:@"todo" code:1 userInfo:@{@"exception": exception}];
    }
    return NO;
}

+ (id)doTryObj:(id(^)())block error:(NSError **)err {
    @try {
        return block();
    }
    @catch (NSException *exception) {
        *err = [NSError errorWithDomain:@"todo" code:1 userInfo:@{@"exception": exception}];
    }
    return nil;
}
@end