Add backward-delete-char/eof action (#1891)

'backward-delete-char/eof' will either abort if query is
empty or delete one character backwards.

man/man1/fzf.1

@@ -639,6 +639,7 @@ A key or an event can be bound to one or more of the following actions.
     \fBaccept-non-empty\fR          (same as \fBaccept\fR except that it prevents fzf from exiting without selection)
     \fBbackward-char\fR             \fIctrl-b  left\fR
     \fBbackward-delete-char\fR      \fIctrl-h  bspace\fR
+    \fBbackward-delete-char/eof\fR  (same as \fBbackward-delete-char\fR except aborts fzf if query is empty)
     \fBbackward-kill-word\fR        \fIalt-bs\fR
     \fBbackward-word\fR             \fIalt-b   shift-left\fR
     \fBbeginning-of-line\fR         \fIctrl-a  home\fR
@@ -647,7 +648,7 @@ A key or an event can be bound to one or more of the following actions.
     \fBclear-selection\fR           (clear multi-selection)
     \fBclear-query\fR               (clear query string)
     \fBdelete-char\fR               \fIdel\fR
-    \fBdelete-char/eof\fR       \fIctrl-d\fR
+    \fBdelete-char/eof\fR           \fIctrl-d\fR (same as \fBdelete-char\fR except aborts fzf if query is empty)
     \fBdeselect-all\fR              (deselect all matches)
     \fBdown\fR                      \fIctrl-j  ctrl-n  down\fR
     \fBend-of-line\fR               \fIctrl-e  end\fR

src/options.go

@@ -740,6 +740,8 @@ func parseKeymap(keymap map[int][]action, str string) {
 				appendAction(actBackwardChar)
 			case "backward-delete-char":
 				appendAction(actBackwardDeleteChar)
+			case "backward-delete-char/eof":
+				appendAction(actBackwardDeleteCharEOF)
 			case "backward-word":
 				appendAction(actBackwardWord)
 			case "clear-screen":

src/terminal.go

@@ -187,6 +187,7 @@ const (
 	actAcceptNonEmpty
 	actBackwardChar
 	actBackwardDeleteChar
+	actBackwardDeleteCharEOF
 	actBackwardWord
 	actCancel
 	actClearScreen
@@ -1846,6 +1847,13 @@ func (t *Terminal) Loop() {
 					t.input = []rune{}
 					t.cx = 0
 				}
+			case actBackwardDeleteCharEOF:
+				if len(t.input) == 0 {
+					req(reqQuit)
+				} else if t.cx > 0 {
+					t.input = append(t.input[:t.cx-1], t.input[t.cx:]...)
+					t.cx--
+				}
 			case actForwardChar:
 				if t.cx < len(t.input) {
 					t.cx++

test/test_go.rb

@@ -1710,6 +1710,20 @@ class TestGoFZF < TestBase
     tmux.until { |lines| lines.match_count.zero? }
     tmux.until { |lines| !lines[-2].include?('(1)') }
   end
+
+  def test_backward_delete_char_eof
+    tmux.send_keys "seq 1000 | #{fzf "--bind 'bs:backward-delete-char/eof'"}", :Enter
+    tmux.until { |lines| lines[-2] == '  1000/1000' }
+    tmux.send_keys '11'
+    tmux.until { |lines| lines[-1] == '> 11' }
+    tmux.send_keys :BSpace
+    tmux.until { |lines| lines[-1] == '> 1' }
+    tmux.send_keys :BSpace
+    tmux.until { |lines| lines[-1] == '>' }
+    tmux.send_keys :BSpace
+    tmux.prepare
+  end
+
 end
 
 module TestShell