Add a binding to get a keystring

[mgraham]

When editing Vim's config file, I can press CTRL-V and then press a key. This will show me the keycode for that key as Vim understands it.

For instance, with my wacky keyboard mapping, CAPS-A is mapped to F18 (don't ask). In Vim's insert mode, pressing CTRL-V followed by CAPS-A inserts <F18>.

However, in qutebrowser, pressing CAPS-A seems to insert the clipboard contents at the cursor position. I'd like to debug this.

Is there any way of seeing what key code qutebrowser is receiving?

[The-Compiler]

I just add a minimal script to print keypresses - use python3 -m scripts.keytester to launch it.

I'll probably add Ctrl-V to the input bar in the future though, as it's useful for keybindings indeed. Though that'd shadow Ctrl-V for pasting from clipboard...

[The-Compiler]

Partial patch by @Carpetsmoker in #958:

From 26e2999ca144bc9188f3bde120c9f0cddce31fcf Mon Sep 17 00:00:00 2001
From: Martin Tournoij <martin@arp242.net>
Date: Fri, 18 Sep 2015 14:15:01 +0200
Subject: [PATCH] Add a command to show the keystring for a key.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This fixes at least part of #658. Note that this is not the same as <C-v> in
Vim. In Vim, <C-v> is used to insert keys (not show their keystring). You can do
cool stuff like <C-v>x07 to insert 0x07, or `<C-v>u2713` to insert ✓

Adding that to the input bar and/or insert mode in text forms is another thing
altogether...

I've mapped in to <C-k> by the way, as <C-v> is already taken...
---
 doc/help/commands.asciidoc       |  5 +++++
 qutebrowser/config/configdata.py |  3 +++
 qutebrowser/keyinput/modeman.py  | 28 +++++++++++++++++++++++++++-
 qutebrowser/utils/message.py     |  7 ++++++-
 4 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/doc/help/commands.asciidoc b/doc/help/commands.asciidoc
index 0125229..6748345 100644
--- a/doc/help/commands.asciidoc
+++ b/doc/help/commands.asciidoc
@@ -813,6 +813,7 @@ How many steps to zoom out.
 |<<scroll-px,scroll-px>>|Scroll the current tab by 'count * dx/dy' pixels.
 |<<search-next,search-next>>|Continue the search to the ([count]th) next term.
 |<<search-prev,search-prev>>|Continue the search to the ([count]th) previous term.
+|<<show-keystring,show-keystring>>|Show the keystring for the next pressed key.
 |<<toggle-selection,toggle-selection>>|Toggle caret selection mode.
 |==============
 [[clear-keychain]]
@@ -1165,6 +1166,10 @@ Continue the search to the ([count]th) previous term.
 ==== count
 How many elements to ignore.

+[[show-keystring]]
+=== show-keystring
+Show the keystring for the next pressed key.
+
 [[toggle-selection]]
 === toggle-selection
 Toggle caret selection mode.
diff --git a/qutebrowser/config/configdata.py b/qutebrowser/config/configdata.py
index 53c95bd..1b5b92e 100644
--- a/qutebrowser/config/configdata.py
+++ b/qutebrowser/config/configdata.py
@@ -1178,6 +1178,8 @@ def data(readonly=False):
 # with Shift. For special keys (with `<>`-signs), you need to explicitly add
 # `Shift-` to match a key pressed with shift.  You can bind multiple commands
 # by separating them with `;;`.
+#
+# You can use <Ctrl-k> to get the name of a key.
 """

 KEY_SECTION_DESC = {
@@ -1355,6 +1357,7 @@ def data(readonly=False):
         ('open qute:settings', ['Ss']),
         ('follow-selected', RETURN_KEYS),
         ('follow-selected -t', ['<Ctrl-Return>', '<Ctrl-Enter>']),
+        ('show-keystring', ['<Ctrl-k>']),
     ])),

     ('insert', collections.OrderedDict([
diff --git a/qutebrowser/keyinput/modeman.py b/qutebrowser/keyinput/modeman.py
index 6906a87..f7fee55 100644
--- a/qutebrowser/keyinput/modeman.py
+++ b/qutebrowser/keyinput/modeman.py
@@ -28,7 +28,7 @@
 from qutebrowser.keyinput import modeparsers, keyparser
 from qutebrowser.config import config
 from qutebrowser.commands import cmdexc, cmdutils
-from qutebrowser.utils import usertypes, log, objreg, utils
+from qutebrowser.utils import usertypes, log, objreg, utils, message


 class KeyEvent:
@@ -125,6 +125,7 @@ class ModeManager(QObject):
         _releaseevents_to_pass: A set of KeyEvents where the keyPressEvent was
                                 passed through, so the release event should as
                                 well.
+        _show_key: Show the next pressed key, and don't do anything.

     Signals:
         entered: Emitted when a mode is entered.
@@ -143,6 +144,7 @@ def __init__(self, win_id, parent=None):
         super().__init__(parent)
         self._win_id = win_id
         self._parsers = {}
+        self._show_key = False
         self.mode = usertypes.KeyMode.normal
         self._releaseevents_to_pass = set()
         self._forward_unbound_keys = config.get(
@@ -310,6 +312,24 @@ def eventFilter(self, event):
         Return:
             True if event should be filtered, False otherwise.
         """
+
+        # The keypress to start "show key mode" also ends up here
+        if self._show_key == 1:
+            self._show_key = 2
+            return True
+
+        if self._show_key == 2:
+            key = utils.keyevent_to_string(event)
+
+            # Only modifier key
+            if key is not None:
+                if len(key) > 1:
+                    key = '<{}>'.format(key)
+                self._show_key = False
+                message.set_text(self._win_id, '')
+                message.info(self._win_id, 'Pressed key: {}'.format(key))
+            return True
+
         if self.mode is None:
             # We got events before mode is set, so just pass them through.
             return False
@@ -322,3 +342,9 @@ def eventFilter(self, event):
     def clear_keychain(self):
         """Clear the currently entered key chain."""
         self._parsers[self.mode].clear_keystring()
+
+    @cmdutils.register(instance='mode-manager', scope='window', hide=True)
+    def show_keystring(self):
+        """Show the keystring for the next pressed key."""
+        message.set_text(self._win_id, 'Press a key')
+        self._show_key = 1
diff --git a/qutebrowser/utils/message.py b/qutebrowser/utils/message.py
index 26bd75b..48a4101 100644
--- a/qutebrowser/utils/message.py
+++ b/qutebrowser/utils/message.py
@@ -141,8 +141,13 @@ def info(win_id, message, immediately=True):
     _wrapper(win_id, 'info', message, immediately)


+def set_text(win_id, txt):
+    """Convienience function to set the normal text of the statusbar."""
+    _wrapper(win_id, 'set_text', txt)
+
+
 def set_cmd_text(win_id, txt):
-    """Convienience function to Set the statusbar command line to a text."""
+    """Convienience function to set the statusbar command line to a text."""
     _wrapper(win_id, 'set_cmd_text', txt)

My comments:

---

This seems to show k as K and Shift+k as <Shift+K>. That probably should show up as k or K instead.

Something like this would work:

txt = event.text()
if len(txt) == 1 and unicodedata.category(txt) != 'Cc':
    key = txt    
else:
    key = utils.keyevent_to_string(event)

---

I think it'd be nicer to make _show_key an enum, e.g. ShowKeyState = usertypes.enum('ShowKeyState', 'ignore, capture') on class level, and then something like this here:

if self._show_key == self.ShowKeyState.ignore:
    self._show_key = self.ShowKeyState.capture

...

---

Hm, I also wonder if this should really be a command (or a keybinding) in general - what about some workflow like this:

• Invoke :bind without any key given
• Key press prompt shows, user presses key
• Commandline is filled with :bind <Key>

Is this functionality needed outside of :bind?