Re: Extending zed

[Oliver Kiddle <okiddle@yahoo.co.uk>]

Sebastian Gniazdowski wrote:
> I've looked at the undo problem. Ctrl-/ (or Ctrl-_ that's the same
> control code as we know) works fine in insert mode, i.e. it does do
> undo. I've checked it's bound to widget "undo" (checking code at the
> end of post). Then I've checked the not-working "u" in zed-vicmd
> keymap. It is also bound to widget "undo". But it makes viewport
> blank, doesn't do smooth undo like Ctrl-/. What is the way out of
> this? Shoud vicmd keymap bind to vi-undo-change? Docs suggest it is a
> one-time undo.

We can prevent the viewport clearing by setting UNDO_LIMIT_NO in an
initialisation widget.

An init function setup in the bind mode seems useful anyway. Perhaps for
vi users it should also contain zle vi-cmd-mode. (I alias vared to vared
-i vi-cmd-mode). I followed the naming of the __zed_pg_up widgets in
naming this __zed_init but I'm not especially fond of this – it looks
like a completion function.

vi-undo-change was once the default. It alternates between undoing
and redoing just the last change. undo acts in a vim compatible way:
multiple undos with a separate redo widget. Other mechanisms are
perhaps better: nvi uses u followed by . to do multiple undo. However,
multiple undo is very useful and the vim mechanism is what we have
implemented so it is the default.

Undoing individual characters at a time is not how undo works in vi or
vim. You can bind a key to undo in viins and it'll do that. Otherwise,
undo events are merged when you go into vi command mode allowing
vi-compatible undo behaviour of undoing whole vi changes.

If you want undo from vicmd to be somewhat more fine-grained, you can
call split-undo from within certain widgets. Redefining self-insert to
call split-undo should work, for example.

By the way, the change in 42929 to bind Home and End seems harmless
enough given that PgUp/Down is already there. I'm not so sure about
the use of zle -la to test for widgets existing (zle -N is silent and
idempotent anyway).

Oliver

diff --git a/Functions/Misc/zed b/Functions/Misc/zed
index f571daf5e..94938871e 100644
--- a/Functions/Misc/zed
+++ b/Functions/Misc/zed
@@ -67,6 +67,12 @@ if (( bind )) || ! bindkey -M zed >&/dev/null; then
   # zed we may want to set this temporally.
   bindkey -A main zed-normal-keymap
 
+  # Define a widget to use at startup, undo shouldn't clear initial buffer
+  __zed_init() {
+    UNDO_LIMIT_NO=$UNDO_CHANGE_NO
+  }
+  zle -N __zed_init
+
   # Assign some default keys.
   # Depending on your stty's, you may be able to use ^J as accept-line, else:
 
@@ -105,11 +111,11 @@ if ((fun)) then
     var="${(q-)1} () {
 }"
   fi
-  vared -M zed -m zed-vicmd var && eval function "$var"
+  vared -M zed -m zed-vicmd -i __zed_init var && eval function "$var"
 else
   zed_file_name=$1
   [[ -f $1 ]] && var="$(<$1)"
-  while vared -M zed -m zed-vicmd var
+  while vared -M zed -m zed-vicmd -i __zed_init var
   do
     {
       print -r -- "$var" >| $zed_file_name