ObjRuby

A fork of GNUstep's RIGS, updated for modern verions of macOS and Ruby.

Requirements

• Ruby 3.2, 3.3, or 3.4 (macOS's default, Ruby 2.6.10, is also supported)
• macOS 13, 14, or 15

Installation

Be sure you have Xcode Command Line Tools installed

$ xcode-select --install

Then you can run:

$ sudo gem install obj_ruby

Or you can include in your Gemfile:

gem 'obj_ruby', '~> 0.1'

Usage

ObjRuby imports Objective-C classes dynamically at runtime. As an example, here is how you can import the NSDate class into Ruby's namespace by using the Foundation framework.

require "obj_ruby"
require "obj_ruby/foundation"

date = ObjRuby::NSDate.dateWithTimeIntervalSince1970(42424242)
other_date = date.addTimeInterval(1000)
earlier_date = date.earlierDate(other_date)

puts earlier_date.isEqualToDate(date) # true

Note you are allowed to mix some Ruby and Objective-C types. The following Ruby types will automatically bridge to these Objective-C types:

Ruby	Objective-C
String	NSString
Numeric, True, False	Immediate or NSNumber
Time	NSDate
Array	NS{Mutable}Array
Hash	NS{Mutable}Dictionary
Set	NS{Mutable}Set

require "obj_ruby"
require "obj_ruby/foundation"

# bridging manually
ary1 = ObjRuby::NSMutableArray.arrayWithObjects(
  ObjRuby::NSNumber.numberWithInt(1),
  ObjRuby::NSNumber.numberWithInt(2),
  ObjRuby::NSNumber.numberWithInt(3),
  nil
)
ary1.addObject(ObjRuby::NSNumber.numberWithInt(4))

# bridging with coercion helpers
ary2 = ObjRuby::NSMutableArray([1,2,3])
ary2 << 4

puts ary1 == ary2 # true

Other frameworks, like the AppKit framework for graphical user interfaces, are also supported.

require "obj_ruby"
require "obj_ruby/app_kit"

app = ObjRuby::NSApplication.sharedApplication
app.activationPolicy = ObjRuby::NSApplicationActivationPolicyRegular
app.activateIgnoringOtherApps(true)

alert = ObjRuby::NSAlert.new
alert.messageText = "Hello world!"

alert.runModal

Subclasses of ObjRuby::NSObject can also be used for delegates such as NSApplicationDelegate.

require "obj_ruby"
require "obj_ruby/app_kit"

# NSApplicationDelegate
class AppDelegate < ObjRuby::NSObject
  def applicationShouldTerminateAfterLastWindowClosed(_)
    true
  end
end

app = ObjRuby::NSApplication.sharedApplication
app.activationPolicy = ObjRuby::NSApplicationActivationPolicyRegular
app.delegate = AppDelegate.new

window = ObjRuby::NSWindow.alloc.initWithContentRect_styleMask_backing_defer(
  ObjRuby::NSMakeRect(0, 0, 300, 200),
  ObjRuby::NSTitledWindowMask | ObjRuby::NSWindowStyleMaskClosable,
  ObjRuby::NSBackingStoreBuffered,
  false
)
window.cascadeTopLeftFromPoint(ObjRuby::NSMakePoint(20, 20))
window.title = "Hello, from ObjRuby!"
window.makeKeyAndOrderFront(nil)

app.activateIgnoringOtherApps(true)
app.run

For more examples, see this projects spec folder.

Credit

ObjRuby is a fork of GNUstep's RIGS, which according to it's author/maintainer Laurent Julliard:

was built in my spare time when my 3 children are in bed :-)

It's really a testimate to both Laurent and the Objective-C runtime in general that while much of the original code was written in 2001, an incredible amount of it runs unchanged over 20 years later on modern versions of macOS and Ruby.

License

This project is Copyright © 2025 Ryan Krug. It is free software, and may be redistributed under the terms specified in the LICENSE file.