mobiruby-ios why catch the exception but not putout the error message?

[charlescui]

@masuidrive

mobiruby-ios why catch the exception but not putout the error message?

I define a method with error, the options is not defined.

def show_transition(&blk)
    # completion = Cocoa::Block.new(CFunc::Void, [CFunc::Int]) { |finished|
    #     # puts "in item_trasition blk and finished is : #{finished}"
    #     blk.call(finished) if blk
    # }
    puts "transition animation:#{options}"
    duration = C::Double(2.5)
    # raise @front_view[:superview]
    begin
        # puts "@front_view[:superview]:#{@front_view.ivar[:_superview]}"
    rescue => e
        puts "Exception:#{e}"
    end
    # if @front_view[:superview]
    #   options = Cocoa::Const::UIViewAnimationOptionTransitionFlipFromLeft
    #   Cocoa::UIView._transitionFromView @front_view, :toView, @back_view, :duration, duration, :options, options, :completion, completion
    # else
    #   options = Cocoa::Const::UIViewAnimationOptionTransitionFlipFromRight
    #   Cocoa::UIView._transitionFromView @back_view, :toView, @front_view, :duration, duration, :options, options, :completion, completion
    # end

end

I use the method show_transition in cocoa function call, but the console with rake doesn't output any tips or backtrace or messages.It cause hard to find out the bug!

define C::Void, :touchesBegan, Cocoa::Object, :withEvent, Cocoa::Object do |touches, event|
    puts "Touch began!!!"
    begin
        show_transition{|f|
            puts "Finished:#{f}"
        }
    rescue Exception => e
        puts "Exception in touchBegan:#{e}"
    end
end

So, I try to catche the mruby exception manual,and puts the exception to help debug.

define C::Void, :touchesBegan, Cocoa::Object, :withEvent, Cocoa::Object do |touches, event|
    puts "Touch began!!!"
    show_transition{|f|
        puts "Finished:#{f}"
    }
end

Now, I found the error with the message:

Touch began!!!
Exception in touchBegan:Unknown method options

How to debug the mruby code in mobiruby-ios?
Why not raise the error out?