# Irb Tab completion problem in Emacs **URL:** \ **Category:** ruby-talk\ **Created:** [20 November 2017 16:30 UTC](https://rubytalk.org/t/irb-tab-completion-problem-in-emacs/74400 "2017-11-20T16:30:33Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Nicola\_Mingotti](https://avatars.discourse-cdn.com/v4/letter/n/f05b48/32.png) [@Nicola\_Mingotti](https://rubytalk.org/u/Nicola_Mingotti)\ **Post date:** [20 November 2017 16:30 UTC](https://rubytalk.org/t/irb-tab-completion-problem-in-emacs/74400/1 "2017-11-20T16:30:33Z")
Hi everyone, I just installed Ruby 2.4.2 from source. and I am using Emacs 24.4.1 in Debian 8.9. If I run irb in xterm, then Tab-completion \*works\*. If i run irb in an Emacs shell with "M-x shell", then Tab-completion \*does not work\*. If I run irb in an Emacs shell with "M-x ansi-term", then Tab-completion \*works\*. I would like to be able to use irb in Emacs "M-x shell" because there it is easy to move and copy/paste code. Do you know how to achieve this ? I prefer to use an Emacs shell over installing a specialized ".el" just for Ruby. Because Emacs + "M-x shell" + "isend-mode" is what I use for all other programming languages having a REPL . Bye Nicola ---
**Author:** ![Ryan\_Davis1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/ryan_davis1/32/1848_2.png) [@Ryan\_Davis1](https://rubytalk.org/u/Ryan_Davis1)\ **Post date:** [28 November 2017 20:46 UTC](https://rubytalk.org/t/irb-tab-completion-problem-in-emacs/74400/2 "2017-11-28T20:46:45Z")
> Hi everyone, > > I just installed Ruby 2.4.2 from source. > and I am using Emacs 24.4.1 in Debian 8.9. > > If I run irb in xterm, then Tab-completion \*works\*. > > If i run irb in an Emacs shell with "M-x shell", then Tab-completion \*does not work\*. > > If I run irb in an Emacs shell with "M-x ansi-term", then Tab-completion \*works\*. > > I would like to be able to use irb in Emacs "M-x shell" because > there it is easy to move and copy/paste code. This is more of an emacs question than a ruby one… that said, define “works”… Tab is doing what emacs is programmed to do. Fire up `M-x shell RET`, then run irb. At the prompt, type “C-h k TAB” (describe-key) and you’ll see what it is bound to. For me, that’s: > TAB (translated from \) runs the command completion-at-point > (found in shell-mode-map), which is an interactive compiled Lisp > function in ‘minibuffer.el’. > > It is bound to TAB, \ \ \. > > (completion-at-point) > > Perform completion on the text around point. > The completion method is determined by ‘completion-at-point-functions’. which is an emacs function. If you click on the hyperlinked “minibuffer.el” you’ll jump to the source and can poke around… basically, this is running an \*emacs\* completion, rather than sending a tab to irb. You might want to look into using the `inf-ruby` library. For me, TAB is still bound to the same function, but it is running in inf-ruby-mode instead of shell-mode so it’ll be less intrusive to bind TAB to something raw or specific to inf-ruby. inf-ruby-mode (the function) has doco that says: > `TAB' completes the input at point. IRB, Pry and Bond completion is supported. Looks like you want to look at `inf-ruby-completions` and `inf-ruby-completion-at-point`. > **···** > > > On Nov 20, 2017, at 08:30, Nicola Mingotti \ wrote: ---
**Author:** ![Nicola\_Mingotti](https://avatars.discourse-cdn.com/v4/letter/n/f05b48/32.png) [@Nicola\_Mingotti](https://rubytalk.org/u/Nicola_Mingotti)\ **Post date:** [28 November 2017 22:21 UTC](https://rubytalk.org/t/irb-tab-completion-problem-in-emacs/74400/3 "2017-11-28T22:21:29Z")
Thank you a lot for the very detailed explanation ! I will do some experiments as soon as i can Bye Nicola > **···** > > On 28/11/2017 21:46, Ryan Davis wrote: > > > > On Nov 20, 2017, at 08:30, Nicola Mingotti \ wrote: > > > > > > Hi everyone, > > > > > > I just installed Ruby 2.4.2 from source. > > > and I am using Emacs 24.4.1 in Debian 8.9. > > > > > > If I run irb in xterm, then Tab-completion \*works\*. > > > > > > If i run irb in an Emacs shell with "M-x shell", then Tab-completion \*does not work\*. > > > > > > If I run irb in an Emacs shell with "M-x ansi-term", then Tab-completion \*works\*. > > > > > > I would like to be able to use irb in Emacs "M-x shell" because > > > there it is easy to move and copy/paste code. > > > > This is more of an emacs question than a ruby one… that said, define “works”… Tab is doing what emacs is programmed to do. > > > > Fire up `M-x shell RET`, then run irb. At the prompt, type “C-h k TAB” (describe-key) and you’ll see what it is bound to. For me, that’s: > > > > > TAB (translated from \) runs the command completion-at-point > > > (found in shell-mode-map), which is an interactive compiled Lisp > > > function in ‘minibuffer.el’. > > > > > > It is bound to TAB, \ \ \. > > > > > > (completion-at-point) > > > > > > Perform completion on the text around point. > > > The completion method is determined by ‘completion-at-point-functions’. > > > > which is an emacs function. If you click on the hyperlinked “minibuffer.el” you’ll jump to the source and can poke around… basically, this is running an \*emacs\* completion, rather than sending a tab to irb. > > > > You might want to look into using the `inf-ruby` library. For me, TAB is still bound to the same function, but it is running in inf-ruby-mode instead of shell-mode so it’ll be less intrusive to bind TAB to something raw or specific to inf-ruby. > > > > inf-ruby-mode (the function) has doco that says: > > > > > `TAB' completes the input at point. IRB, Pry and Bond completion is supported. > > > > Looks like you want to look at `inf-ruby-completions` and `inf-ruby-completion-at-point`. > > > > Unsubscribe: \ > > \<[http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>](http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>);