cursor shape (e.g. for vim mode)

[davidszotten]

hey, thanks for an awesome library!

would it be possible to support cursor shapes, like https://hamberg.no/erlend/posts/2014-03-09-change-vim-cursor-in-iterm.html (or http://vim.wikia.com/wiki/Change_cursor_shape_in_different_modes)

[jonathanslenders]

Hey @davidszotten,

That is probably possible, yes. Although I need to have a look how to implement this cleanly [1] and making sure that most terminals understand it. It's not a priority for me right now, but I'll put it on the to-do list.

Jonathan

[1] The tricky part is that the Vi state (insert/navigation) is currently not available from the CLI/renderer and the state is not able to access the renderer. So, I'm not sure yet how to make it fit cleanly in the architecture.

[sassanh]

@jonathanslenders What about dirty temporary workarounds for endusers? It's not healthy for vim users to work with wrong cursor shape 😉
Is there anything like a signal fired when vim mode is changed so that we can print the appropriate character sequence to terminal that it changes the cursor shape? I know the character sequences that change cursor shape for my terminal, so if we have those signals and a way to print to terminal when those signals are fired we can have temporary workarounds for our setups.

[jonathanslenders]

Hi @sassanh, I understand that this is useful. But so far I did not had time yet (actually it wasn't a priority). If you have a patch, then I'm more than happy to review it. Otherwise, I'll have a look at this later on myself. Probably it needs to go somewhere in the Renderer class, but I'm not sure what's the best approach.

[jonathanslenders]

Other question: is there somewhere some official documentation about escape sequences for cursor shapes? Which terminals support it? Do all terminals use the same escape sequences? And if not, how do I know which escape sequences to use?

[sassanh]

@jonathanslenders I understand, no rush. Just wanted to know if I can use a temporary hacky solution to acheive this till you have time to implement it.
When I was using vim (not neovim) I had some vimscript in my vimrc file to change the cursor shape for iTerm in vim as vim didn't do it by itself on iTerm. After upgrading to neovim I removed those lines as neovim handles it by itself. But neovim is the only application I know that handles it by itself. I had to customize readline configuration to achieve this for bash/ipython<5/psql/etc. I had to customize fish for this purpose too. So I guess it's totally alright for prompt-toolkit to let the user do it by himself and just gives the user the ability to print required sequences when special events occur in prompt-toolkit. I don't expect it to handle it by itself as even bash didn't handle it. Giving the user the ability to print some text to terminal when special events occur in prompt-line may be helpful for other situations too. User will be able to change color of things, print bell sequence, etc.

[sassanh]

It may be helpful: http://vim.wikia.com/wiki/Change_cursor_shape_in_different_modes

[joelostblom]

This would be really useful! Especially since the python-prompt-toolkit has such great support for multiline commands (thanks so much for that!), there is now more incentive to use vi-mode for command editing.

In terms of escape sequences, the snippet below is what I am using for cursor shape changes in zsh for gnome-terminal and terminator (there are more approaches for zsh listed over at the Unix & Linux SE.).

bindkey -v
# Remove delay when entering normal mode (vi)
KEYTIMEOUT=5
# Change cursor shape for different vi modes.
function zle-keymap-select {
  if [[ $KEYMAP == vicmd ]] || [[ $1 = 'block' ]]; then
    echo -ne '\e[1 q'
  elif [[ $KEYMAP == main ]] || [[ $KEYMAP == viins ]] || [[ $KEYMAP = '' ]] || [[ $1 = 'beam' ]]; then
    echo -ne '\e[5 q'
  fi
}
zle -N zle-keymap-select
# Start with beam shape cursor on zsh startup and after every command.
zle-line-init() { zle-keymap-select 'beam'}

The escape sequences I am using here (\e[1 q and \e[5 q) are not universal for all terminal emulator (this blog suggest that it is \E]50;CursorShape=0\C-G and \E]50;CursorShape=1\C-G for iTerm2). So the most flexible approach might be if there is a signal emitted when the vi-mode changes, similar to what @sassanh suggested, and then leave it up to the user to specify in their configuration file the appropriate escape sequence to be inserted for their terminal.

Edit: I asked this on SO just before finding this issue

[amzyang]

I've made a quick and dirty change. It works well for me (on iterm2).

diff --git i/prompt_toolkit/eventloop/base.py w/prompt_toolkit/eventloop/base.py
index db86fac..c9e2173 100644
--- i/prompt_toolkit/eventloop/base.py
+++ w/prompt_toolkit/eventloop/base.py
@@ -9,7 +9,7 @@ __all__ = (
 
 
 #: When to trigger the `onInputTimeout` event.
-INPUT_TIMEOUT = .5
+INPUT_TIMEOUT = .05
 
 
 class EventLoop(with_metaclass(ABCMeta, object)):
diff --git i/prompt_toolkit/key_binding/vi_state.py w/prompt_toolkit/key_binding/vi_state.py
index 92ce3cb..81dd6d0 100644
--- i/prompt_toolkit/key_binding/vi_state.py
+++ w/prompt_toolkit/key_binding/vi_state.py
@@ -1,3 +1,4 @@
+from __future__ import print_function
 from __future__ import unicode_literals
 
 __all__ = (
@@ -59,3 +60,18 @@ class ViState(object):
         self.waiting_for_digraph = False
         self.operator_func = None
         self.operator_arg = None
+
+    @property
+    def input_mode(self):
+        return self._input_mode
+
+    @input_mode.setter
+    def input_mode(self, mode):
+        cursor_shape = '\x1b[5 q'
+        if mode == InputMode.NAVIGATION:
+            cursor_shape = '\x1b[1 q'
+        elif mode == InputMode.REPLACE:
+            cursor_shape = '\x1b[3 q'
+
+        print(cursor_shape, end='')
+        self._input_mode = mode

[sassanh]

@grassofhust Thanks. Now I'm happy too.

[kovidgoyal]

And here is code you can add to your ipython_config.py to avoid needing to patch prompt_toolkit

# Set vi keybindings
import sys
from prompt_toolkit.key_binding.vi_state import InputMode, ViState


def get_input_mode(self):
    return self._input_mode


def set_input_mode(self, mode):
    shape = {InputMode.NAVIGATION: 1, InputMode.REPLACE: 3}.get(mode, 5)
    out = getattr(sys.stdout, 'buffer', sys.stdout)
    out.write(u'\x1b[{} q'.format(shape).encode('ascii'))
    sys.stdout.flush()
    self._input_mode = mode


ViState._input_mode = InputMode.INSERT
ViState.input_mode = property(get_input_mode, set_input_mode)
c.TerminalInteractiveShell.editing_mode = 'vi'

[kovidgoyal]

@jonathanslenders The vast majority of terminals support the escape code of the form <ESC>[<number><space>q for changing cursor shapes (the most glaring exception I know of on linux is konsole). The ones that dont should really be fixed to support it. It is documented here: http://invisible-island.net/xterm/ctlseqs/ctlseqs.html (see the q CSI escape code)

[kovidgoyal]

And here is modified code for ipython_config.py that also allows mapping of jj to exit insert mode:

# Set vi keybindings
import sys
from operator import attrgetter
from prompt_toolkit.key_binding.vi_state import InputMode, ViState
import prompt_toolkit.key_binding.defaults as pt_defaults
from prompt_toolkit.filters.cli import ViInsertMode
from prompt_toolkit.keys import Keys


def set_input_mode(self, mode):
    shape = {InputMode.NAVIGATION: 1, InputMode.REPLACE: 3}.get(mode, 5)
    out = getattr(sys.stdout, 'buffer', sys.stdout)
    out.write(u'\x1b[{} q'.format(shape).encode('ascii'))
    sys.stdout.flush()
    self._input_mode = mode


ViState._input_mode = InputMode.INSERT
ViState.input_mode = property(attrgetter('_input_mode'), set_input_mode)
orig_bindings_func = pt_defaults.load_vi_bindings


def load_vi_bindings(*a, **kw):
    registry = orig_bindings_func(*a, **kw)
    esc_handler = registry.get_bindings_for_keys((Keys.Escape,))[-1].handler
    # Use jj to exit insert mode
    registry.add_binding('j', 'j', filter=ViInsertMode())(esc_handler)
    return registry

pt_defaults.load_vi_bindings = load_vi_bindings
c.TerminalInteractiveShell.editing_mode = 'vi'

[sassanh]

The only thing that remains for me is preserving the input mode, currently new prompt line always comes in insert mode, but I want it to preserve the input mode from last line. Do you have any idea for that?

[kovidgoyal]

No idea, as I dont need this, I have not spent the time to look, but probably this belongs in ipython not prompt_toolkit as presumably state between consecutive prompts is not stored in prompt toolkit but in whatever program is calling it.