Use `em_delete` in `key_delete` (#504)

* Test existing behavior

Typing Ctrl-D ends editing but typing <Del> does not.

Also renamed a test that is not testing ed_delete_next_char but
key_delete.

* Check if line empty first in em_delete

By distributivity of AND over OR, we can factor out this condition. This
will make the next commit simpler.

* Use em_delete in key_delete

When the editing mode is emacs, use `em_delete` in `key_delete`. We need
to add a condition though to `em_delete`, because it implements both
`delete-char` and `end-of-file`. We only want the `end-of-file` behavior
is the key is really Ctrl-D.

This matches the behavior of the <Del> key with readline, i.e. deleting
the next character if there is one, but not moving the cursor, while not
finishing the editing if there are no characters.

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/reline/line_editor.rb b/lib/reline/line_editor.rb
index 6e34c28b53..6e2bd59f05 100644
--- a/lib/reline/line_editor.rb
+++ b/lib/reline/line_editor.rb
@@ -1940,8 +1940,10 @@ class Reline::LineEditor
   end
 
   private def key_delete(key)
-    if @config.editing_mode_is?(:vi_insert, :emacs)
+    if @config.editing_mode_is?(:vi_insert)
       ed_delete_next_char(key)
+    elsif @config.editing_mode_is?(:emacs)
+      em_delete(key)
     end
   end
 
@@ -2647,7 +2649,7 @@ class Reline::LineEditor
   alias_method :kill_whole_line, :em_kill_line
 
   private def em_delete(key)
-    if (not @is_multiline and @line.empty?) or (@is_multiline and @line.empty? and @buffer_of_lines.size == 1)
+    if @line.empty? and (not @is_multiline or @buffer_of_lines.size == 1) and key == "\C-d".ord
       @line = nil
       if @buffer_of_lines.size > 1
         scroll_down(@highest_in_all - @first_line_started_from)