IRuby with irb v1.13.0 doesn't show output cells

[hypsakata]

I've encountered an issue where it seems that IRuby may not be compatible with irb v1.13.0. I've attached screenshots showing IRuby 0.7.4 running with irb v1.12.0 and irb v1.13.0 on the latest official Ruby docker image.

In the case of irb v1.12.0, IRuby is able to display output cells as expected. However, when running with irb v1.13.0, IRuby does not display these output cells. A similar phenomenon occurred in IRuby obtained by specific_install, although a screenshot is not attached.

I hope this information is helpful.
Thanks

Screenshots

IRuby + irb 1.12.0

IRuby + irb 1.13.0

[zalt50]

#339 works for me.