vim use of keydown and keypress preventing codemirrorIgnore?

[dalejung]

As far as I can tell, the move to on('keydown') and on('keypress')` is circumventing the normal way of preventing codemirror from doing things with events.

What's the proper way to register a keyevent handler that can prevent the keymap from firing?

[dalejung]

diff --git i/keymap/vim.js w/keymap/vim.js
index 558e4c8..f884f7b 100644
--- i/keymap/vim.js
+++ w/keymap/vim.js
@@ -251,6 +251,7 @@
     // Keys with modifiers are handled using keydown due to limitations of
     // keypress event.
     function handleKeyDown(cm, e) {
+      if(e.codemirrorIgnore) { return; }
       var name = lookupKey(e);
       if (!name) { return; }

@@ -262,6 +263,7 @@
     // Keys without modifiers are handled using keypress to work best with
     // non-standard keyboard layouts.
     function handleKeyPress(cm, e) {
+      if(e.codemirrorIgnore) { return; }
       var code = e.charCode || e.keyCode;
       if (e.ctrlKey || e.metaKey || e.altKey ||
           e.shiftKey && code < 32) { return; }

this helped give me the behavior that I wanted. The other issue is that I have to modify the _handlers array directly since on() doesn't give me the ability to insert a handler before the vim keymap handlers.

[mightyguava]

You could register your handler before turning on the vim mode, i.e.

var editor = CodeMirror.fromTextArea(...);
// register handlers
editor.setOption('vimMode', true);

and that should put your handlers before vim gets it.

[dalejung]

How would I cancel vim handling for certain events?

[mightyguava]

I suppose vim mode could check for preventDefault and codemirrorIgnore values on the event and ignore it if either is set. Would that solve your problem?

[dalejung]

Yeah, that how I patched my local CodeMirror. I think it's the wrong place to handle it, but we'd need to split handlers into app and internal in order to remove it.

[mightyguava]

Tricky problem. @marijnh do you have any suggestions on a good way for clients to suppress keypress and keydown handlers registered on CodeMirror instances?

[marijnh]

I think it would be preferable to move the vim mode's key handling down into the keymap layer again, which has at least some concept of priorities and fine-grained handling. Would it work for you to be able to add a function to a keymap that is simply called for each key, and which can return a value indicating whether it chose to handle that key? You'd have to translate from CodeMirror-style key names to Vim-style names, but that's probably not very hard.

[mightyguava]

Yes, that's probably a good idea. I didn't realize until after I finished the insert mode key handling work that I didn't actually have to move the key handling out of the keymap layer.

A function on the keymap that is called for each key would make the vim code cleaner if we take this approach.

[marijnh]

Attached patch should allow you to give the vim keymap(s) a call method (or just make them functions). This method will be called with the name of a key, and should return null if there is no binding, and a function when there is one. That function will then be called with a CodeMirror instance as argument to actually execute the binding's action.

You might also want to take a look at the new functionality for multi-stroke key bindings. Basically, if you return "..." from a keymap, the key will be stored, and combined with the next key, so that if you press Ctrl-X and that returns "...", and then you press F, the string "Ctrl-X F" will be dispatched to the keymap. This might be too primitive for the vim map's use, I'm not sure.

[marijnh]

By the way, if you need access to the editor state during dispatch, I am also open to passing the editor instance as second argument to the keymap function. It's less clean, but I could live with it.

[mightyguava]

I took a crack at this today, and realized I do need the editor instance. Vim mode's key mappings can change depending on its current state

[marijnh]

Attached patch causes the editor instance to be passed as second argument to the keymap's call method.