PATCH: edit-command-line: restrict editing to region if it is active

[Mikael Magnusson <mikachu@gmail.com>]

---
 Functions/Zle/edit-command-line | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/Functions/Zle/edit-command-line b/Functions/Zle/edit-command-line
index 8aaeb738e5..3781244b27 100644
--- a/Functions/Zle/edit-command-line
+++ b/Functions/Zle/edit-command-line
@@ -7,9 +7,20 @@
 # except that it will handle multi-line buffers properly.
 
 emulate -L zsh
-local prebuffer
-# see below comment for why this is needed
-if (( ! ZLE_RECURSIVE )); then
+local left right prebuffer buffer=$BUFFER lbuffer=$LBUFFER
+# set up parameters depending on which context we are called from,
+# see below comment for more details
+if (( REGION_ACTIVE )); then
+  if (( CURSOR < MARK )); then
+    left=$CURSOR right=$MARK
+    lbuffer=
+  else
+    left=$MARK right=$CURSOR
+    lbuffer[right-left,-1]=
+  fi
+  (( left++ ))
+  buffer=$BUFFER[left,right]
+elif (( ! ZLE_RECURSIVE )); then
   prebuffer=$PREBUFFER
 fi
 
@@ -29,10 +40,10 @@ fi
   fi
   case $editor in
     (*vim*)
-      integer byteoffset=$(( $#PREBUFFER + $#LBUFFER + 1 ))
+      integer byteoffset=$(( $#prebuffer + $#lbuffer + 1 ))
       "${(@)editor}" -c "normal! ${byteoffset}go" -- $1;;
     (*emacs*)
-      local lines=( "${(@f):-"$PREBUFFER$LBUFFER"}" )
+      local lines=( "${(@f):-"$prebuffer$lbuffer"}" )
       "${(@)editor}" +${#lines}:$((${#lines[-1]} + 1)) $1;;
     (*) "${(@)editor}" $1;;
   esac
@@ -48,13 +59,24 @@ fi
   #   the following point)
   # - when we are at PS2 (CONTEXT == cont && ! ZLE_RECURSIVE) we do want the
   #   break or otherwise the text from PREBUFFER will be inserted twice
+  # - when the region is active, we only want to change the parts of BUFFER
+  #   covered by the region, and any PREBUFFER stays as PREBUFFER
   # - in all other cases (that I can think of) we also just want to set
   #   $BUFFER directly.
-  if [[ $CONTEXT != cont ]] || (( ZLE_RECURSIVE )); then
+  if (( REGION_ACTIVE )); then
+    # adjust the length of the region to the length of the edited text
+    local prelen=$#BUFFER
+    BUFFER[left,right]="$(<$1)"
+    if (( MARK > CURSOR )); then
+      (( MARK += $#BUFFER - prelen ))
+    else
+      (( CURSOR += $#BUFFER - prelen ))
+    fi
+  elif [[ $CONTEXT != cont ]] || (( ZLE_RECURSIVE )); then
     BUFFER="$(<$1)" 
   else
     print -Rz - "$(<$1)"
     zle send-break
   fi
 
-} =(<<<"$prebuffer$BUFFER")
+} =(<<<"$prebuffer$buffer")
-- 
2.15.1