Always set ANSI CSI keybindings for Home, End, and Arrow. by tompng · Pull Request #569 · ruby/reline

tompng · 2023-07-11T20:30:18Z

Fixes HOME key, END key, Meta + Arrow key problem in some terminal emulator.

ANSI cursor sequence

Most terminals are vt100 compatible. In vt100 normal mode, ANSI cursor sequence "\e[A", "\e[B", "\e[C", "\e[D" will be sent on arrow key press.
("Cursor Control" section of https://vt100.net/docs/vt100-ug/chapter3.html, "Minimum requirements for VT100 emulation" section of https://www.real-world-systems.com/docs/ANSIcode.html)
These arrow key sequence are normally not written in terminfo. This pull request make Reline bind these cursor sequences as default.

HOME \e[H and END \e[F keys are also categorized as cursor sequence. You can check this by setting Cursor Key Mode (DECCKM). HOME/END key will change the behavior just like arrow key does.

# This hack is not needed anymore.
when 'cuu', 'cud', 'cuf', 'cub'
  [ key_code.sub(/%p1%d/, '').bytes, key_binding ]

Modifiers

In https://mdfs.net/Docs/Comp/Comms/ANSIKeys, it says that terminal emulator will add a modifier value like "\e[1;3A" for Meta+Up, "\e[1;5A" for Ctrl+Up. Some terminal emulator uses "\e\e[A" for Meta+Up instead of modifier value.

	Up	Left	Meta + Up	Meta + Left	Ctrl + Up	Ctrl + Left
Terminal.app	\e[A	\e[D	\e\e[A	\eb	\e[A	\e[1;5D
iTerm2	\e[A	\e[D	\e\e[A	\e\e[D	\e[1;5A	\e[1;5D
Alacritty	\e[A	\e[D	\e[1;3A	\e[1;3D	\e[1;5A	\e[1;5D
VSCode Terminal	\e[A	\e[D	\e[1;3A	\eb	\e[1;5A	\e[1;5D

(\eb is handled by Reline::KeyStroke#compress_meta_key)

This pull request also bind these arrow + modifier key sequences.

Reduce comprehensive list

Some bytes in set_default_key_bindings_comprehensive_list will be registered as default. I've removed them from comprehensive_list.

tompng · 2023-07-11T20:32:47Z

lib/reline/ansi.rb

-      [27, 91, 49, 59, 53, 67] => :em_next_word, # Ctrl+→, extended entry
-      [27, 91, 49, 59, 53, 68] => :ed_prev_word, # Ctrl+←, extended entry
-      [27, 91, 49, 59, 51, 67] => :em_next_word, # Meta+→, extended entry
-      [27, 91, 49, 59, 51, 68] => :ed_prev_word, # Meta+←, extended entry


"\e[1;5C", "\e[1;5D", "\e[1;3C", "\e[1;3D" will be bound in set_default_key_bindings_ansi_cursor

tompng · 2023-07-11T20:43:36Z

lib/reline/ansi.rb

-      [27, 27, 91, 67] => :em_next_word,    # Option+→, extended entry
-      [27, 27, 91, 68] => :ed_prev_word,    # Option+←, extended entry
-      [195, 166] => :em_next_word,          # Option+f
-      [195, 162] => :ed_prev_word,          # Option+b


[195, 166] and [195,162] are unicode bytes for æ and â. It's not an escape sequence.

In mac, option+f option+b will insert ƒ ∫ in any textarea and also in iTerm2, but we don't want to add 'ƒ'.bytes '∫'.bytes to this list. Same for æ and â.

tompng · 2023-07-11T21:07:09Z

lib/reline/ansi.rb

-        # Escape sequences that omit the move distance and are set to defaults
-        # value 1 may be sometimes sent by pressing the arrow-key.
-        when 'cuu', 'cud', 'cuf', 'cub'
-          [ key_code.sub(/%p1%d/, '').bytes, key_binding ]


# searched cuu from terminfo cuu=\E[%p1%dA cuu=\233%p1%dA cuu=\Ep-%p1%d; cuu=\E&a-%p1%dR cuu=\E[%p1%dA$<5> cuu=\E[%p1%dA$<30> cuu=\037up %p1%d\r cuu=\035up %p1%d;

these are not for input sequence. It's for output sequence like \e[42A = move cursor up 42 rows.
This pattern does not match to \e[A (UP) nor \e[1;2A (UP+SHIFT).
We need to explicitly bind "\e[A", not irrelevant_value.gsub(replace_it, to_match_CSI_A)

tompng · 2023-07-11T21:27:20Z

lib/reline/ansi.rb

+      bindings = [["\e[#{char}", default_func]] # CSI + char
+      if modifiers[:ctrl]
+        # CSI + ctrl_key_modifier + char
+        bindings << ["\e[1;5#{char}", modifiers[:ctrl]]


In https://mdfs.net/Docs/Comp/Comms/ANSIKeys, it says "\e[1;5D" and also "\e[5D" is valid as Ctrl+Left.
Although, I think we only need 1;5 style because set_default_key_bindings_comprehensive_list only had \e[1;5D, emacs and readline only supports \e[1;5D style.

st0012

Generally looks good and the description/comments are easy to follow 👍

2 questions:

Since this PR sets new default bindings, I think it's an enhancement?
Can you provide a few manual test steps to check the behaviour changes? I can perform them on Terminal.app, iTerm2 and VS Code Terminal.

tompng · 2023-07-19T06:26:28Z

enhancement?

I think it is also an enhancement. I added a label.

Manual test steps are

Disable keyboard shortcut for mission control that uses ctrl + arrows
Type foo bar baz to IRB
Press ← → (move cursor), Ctrl+← Ctrl+→ Option+← Option+→ (move to prev/next word), Home(fn+←) End(fn+→) (move to beginning/end of line), ↑ ↓ (move history)
Don't to forget reenable keyboard shortcuts 😄

I think the change will be like this

Keys	Terminal	iTerm	VSCode
left/right	---	---	---
up/down	---	---	---
Ctrl left/right	---	---	---
Option left/right	---	improved	---
Home End	no input	improved	improved

(Terminal.app does not input sequence for Home and End keys)

tompng · 2023-07-19T06:34:53Z

To check the input sequence, use STDIN.raw{STDIN.wait_readable; sleep 0.1; STDIN.readpartial(10)}

sshock · 2023-07-19T07:49:59Z

LGTM

st0012 · 2023-07-19T12:20:01Z

I think the change will be like this

I can confirm these changes with my testing 👍

To check the input sequence, use STDIN.raw{STDIN.wait_readable; sleep 0.1; STDIN.readpartial(10)}

This is a very useful snippet. Can you add it to the Contributing session of README too?

st0012

This is awesome, thank you!

Arrow. (ruby/reline#569) ruby/reline@f363a43a45

Always set ANSI CSI keybindings for Home, End, and Arrow.

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tompng commented Jul 11, 2023

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tompng requested a review from a team July 18, 2023 12:16

st0012 reviewed Jul 18, 2023

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tompng added the enhancement New feature or request label Jul 19, 2023

tompng mentioned this pull request Jul 19, 2023

Always set standard(really?) CSI keybindings #567

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st0012 approved these changes Jul 19, 2023

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tompng merged commit f363a43 into ruby:master Jul 19, 2023

tompng deleted the ansi_keycode_sequence branch July 19, 2023 13:25

matzbot pushed a commit to ruby/ruby that referenced this pull request Jul 19, 2023

[ruby/reline] Always set ANSI CSI keybindings for Home, End, and

ca56148

Arrow. (ruby/reline#569) ruby/reline@f363a43a45

This was referenced Jul 19, 2023

Fix Home and End keys on macOS #521

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DRAFT - Fix Various Home / End key binding issues #462

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Unable to type the character â over an SSH session #518

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Bad chars on home/end/del #435

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This was referenced Jul 19, 2023

Home/End keys on numpad don't move cursor ruby/irb#408

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In macOS, home and end keys no longer work ruby/irb#330

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Bump version to 0.3.7 #578

Merged

tompng mentioned this pull request Jun 8, 2024

Add cursor keys for application keypad mode to default key bindings #719

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tompng mentioned this pull request Oct 13, 2024

Add fiddle runtime dependency #762

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Always set ANSI CSI keybindings for Home, End, and Arrow.#569

Always set ANSI CSI keybindings for Home, End, and Arrow.#569
tompng merged 1 commit intoruby:masterfrom
tompng:ansi_keycode_sequence

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tompng commented Jul 11, 2023 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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ANSI cursor sequence

Modifiers

Reduce comprehensive list

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