Regular Expression String to match function call of Objective C

I am trying with this string to locate first line of every function in my app developed in Objective C: ^-[^{]+{.

This works fine in XCode`s Find>Regular Expression searching.

But when I am trying to use this string in the following function, the function is always returning NULL.

- (void) putLogInFunctionCalls{

    NSString *string = @"- (void)setRepresentedObject:(id)representedObject {";
    NSError *error = nil;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^-[^{]+\{" options:NSRegularExpressionCaseInsensitive error:&error];

    NSString *modifiedString = [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:[NSString stringWithFormat:@"%@ DLOG()", string]];

    NSLog(@"%@", modifiedString);
}

But it should return:

"- (void)setRepresentedObject:(id)representedObject { DLOG()"

This question is specific to detecting a function starting line of Objective-C. Anyone attempting to write meta-codes on iOS/MacOS apps developed in Objective-C might encounter this problem and might find answer usefull. The answer that is marked as duplicate of this one is more generic.