I've been attempting to get an objective-c framework to work with macruby and I believe I've found a bug in the way ruby Proc objects are copied when used as objective-c blocks. The copied block doesn't seem to persist correctly beyond the scope in which it was copied. It isn't deallocated, but calling it results in a crash. Typical error messages are: wrong type NSCFSet (expected Proc) (TypeError) wrong type NSRectSet (expected Proc) (TypeError) I'm guessing that there's a pointer to the wrong memory location? Here's the Objective-C implementation: @implementation TestBlock - (id)initWithBlock:(void (^)())aBlock; { [super init]; block = [aBlock copy]; NSLog(@"Block: %@", block); block(); return self; } - (void)callBlock; { NSLog(@"block: %@", block); block(); } @end Within 'initWithBlock:', the copied block can be invoked without error. Attempting to do so from 'callBlock', results in a crash. The test framework can be used without error when using objective-c. Here's the ruby controller code: @b = TestBlock.alloc.initWithBlock Proc.new { puts "hello from ruby"} # this next line is called from a different scope and causes the crash @b.callBlock 2010-11-19 08:41:06.620 CallObjectiveCBlocks[7046:a0f] Block: <__NSAutoBlock__: 0x200be74a0> hello from ruby 2010-11-19 08:41:20.011 CallObjectiveCBlocks[7046:a0f] block: <__NSAutoBlock__: 0x200be74a0> 2010-11-19 08:41:20.012 CallObjectiveCBlocks[7046:a0f] /Users/alan/Documents/programming/macruby/CallObjectiveCBlocks/build/Debug/CallObjectiveCBlocks.app/Contents/Resources/Controller.rb:21:in `call:': wrong type Array (expected Proc) (TypeError) from /Users/alan/Documents/programming/macruby/CallObjectiveCBlocks/build/Debug/CallObjectiveCBlocks.app/Contents/Resources/rb_main.rb:23:in `<main>'