Saturday, March 16, 2013 [Tweets] [Favorites]

Shebang Objective-C

Nicolas Bouilleaud has a clever trick for making Objective-C source files self-compiling (via Romain Briche):

The idea is to play with shell and C comments so that the file is both a valid shell script and an Objective-C program. The shell script calls clang to compile itself, and then runs the output executable.

I’ve fixed the quoting so that it also works when the path contains a space:

/*/../bin/ls > /dev/null
COMPILED="${0%.*}"
clang "$0" -o "$COMPILED" -framework Foundation;
"$COMPILED"; rm "$COMPILED"; exit;
*/

#import <Foundation/Foundation.h>
  
int main(int argc, char *argv[])
{
    @autoreleasepool
    {
        NSLog(@"Hello %@",NSProcessInfo.processInfo.environment[@"USER"]);
    }
    return 0;
}

Make the .m file executable and you can run it from Terminal. Unfortunately, it won’t run from BBEdit’s #! menu because the file doesn’t actually begin with #!.

2 Comments

[...] See also: Shebang Objective-C. [...]

Here's a simpler version, equivalent to the first five lines:

//bin/echo -n ; clang "$0" -framework Foundation && ./a.out ; rm -f a.out ; exit

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