statusline: Provide overwrite mode indicator

[JoeKar]

We can store the overwrite state in the Buffer instead of the BufPane, which makes it easier to be accessed from the statusline via the statusformatl option.

Closes #3155

[dmaluka]

"Delete" is not exactly what the overwrite mode is about. It is about overwrite aka replace, right?

I'm not sure which string should we display here.

I'm also wondering: can we be space-saving here and display a string only when in overwrite mode (similarly to $(modified))? Then maybe we could even add $(overwrite) to the default value of statusformatl.

Although again, I'm not sure which string should we display then. [overwrite] ? Anything shorter?

[JoeKar]

Even we find something, which we think it fits the needs...there is the one who likes to customize it anyway. 😉

[niten94]

I cannot come up with a better string, but I usually see "INS" displayed on the status bar when overwrite mode is enabled in GUI text editors. I don't think there could be a string with only symbols that can be recognized without confusion.

[dmaluka]

Yeah, I thought about [ins] too. I'm not entirely opposed to it, although arguably it would be a lie, since it is not the "insert mode" but the opposite of it (but hey, we can always say that it is "the mode that is triggered by pressing Insert, hence [ins]).

For reference, what some other editors display in their status lines, FWICS:

• vim: -- REPLACE -- in overwrite mode, -- INSERT -- in normal insert mode
• emacs: Ovwrt in overwrite mode, nothing in normal mode
• geany: OVR in overwrite mode, INS in normal mode
• nano doesn't seem to implement overwrite mode at all, the Insert key triggers something different

[JoeKar]

I'd prefer to keep the normal and default insert mode unmarked, as it is right now and only mark the replace/overwrite mode.
Unfortunately you don't like [>], because it is not self-explaining. 😉

How about [ow]...it is similar to [ro] or shall it be more explicit, but possibly longer?

[dmaluka]

"ow" sounds like "ouch" or something.

[ovr]?

[JoeKar]

over what?
I'm not really convinced.

[I]/[O] or [I]/[R], but then [I] needs to be displayed by default, otherwise [O] or [R] doesn't self explain.
Or as suggested by you initially just [overwrite], which is a bit longer, but explicit and really self explaining.

[dmaluka]

[overwrite] is ok for me.

One more thought: maybe let's make [ro] and [overwrite] mutually exclusive? Since when the buffer is readonly, there is little point in informing the user that we are in overwrite mode, since the user cannot edit (either insert or overwrite) anything anyway.

i.e. a trivial change:

--- a/internal/display/statusline.go
+++ b/internal/display/statusline.go
@@ -48,7 +48,7 @@ var statusInfo = map[string]func(*buffer.Buffer) string{
 		return ""
 	},
 	"overwrite": func(b *buffer.Buffer) string {
-		if b.OverwriteMode {
+		if b.OverwriteMode && !b.Type.Readonly {
 			return "[overwrite] "
 		}
 		return ""

[dmaluka]

since the user cannot edit (either insert or overwrite) anything anyway.

Well, actually currently the user can overwrite characters in a readonly buffer (try it: open help, press Insert and start typing characters), but that's a nasty bug to be fixed (#1805).

[JoeKar]

Good catch, thanks.
#1805 needs to be fixed on its own.

[dmaluka]

We can store the overwrite state in the cursor instead of the bufpane

I think abusing Cursor for that is hacky and wrong, and on top of that completely unnecessary, since we can just store it in Buffer (but not in SharedBuffer, that's the key).

That's the trick we use with LastSearch or HighlightSearch, for example. They are provided by buffer, not by bufpane, so they can be used by display, and yet they are effectively per bufpane, i.e. each bufpane has its own search state even if it shares its buffer with other bufpanes.

[JoeKar]

we can just store it in Buffer (but not in SharedBuffer, that's the key).

Good point, works like a charm!

[matthias314]

Sorry for chiming in late, and please ignore this comment if you think it just makes things more complicated.

I personally find that [overwrite] takes up quite a lot of space in the statusline, at least for a terminal window that is, say, 80 characters wide. What about shortening it to [over]? Something completely different that came to my mind would be to display the cursor position is reverse (foreground and background color exchanged) if in overwrite more.

[JoeKar]

I personally find that [overwrite] takes up quite a lot of space in the statusline

We're aware of the fact that it actually requires a lot space within the statusline and discussed it here:
#3620 (comment)

Unfortunately we didn't came up with a better, shorter and self explaining suggestion.

Something completely different that came to my mind would be to display the cursor position is reverse (foreground and background color exchanged) if in overwrite more.

Hm, something to consider.