ui/text: add ChangeEvent and rename Submit to SubmitEvent

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/text/buffer.go

@@ -21,14 +21,25 @@ type editBuffer struct {
 	// The gap start and end in bytes.
 	gapstart, gapend int
 	text             []byte
+
+	// changed tracks whether the buffer content
+	// has changed since the last call to Changed.
+	changed bool
 }
 
 const minSpace = 5
 
+func (e *editBuffer) Changed() bool {
+	c := e.changed
+	e.changed = false
+	return c
+}
+
 func (e *editBuffer) deleteRuneForward() {
 	e.moveGap(0)
 	_, s := utf8.DecodeRune(e.text[e.gapend:])
 	e.gapend += s
+	e.changed = e.changed || s > 0
 	e.dump()
 }
 
@@ -37,6 +48,7 @@ func (e *editBuffer) deleteRune() {
 	_, s := utf8.DecodeLastRune(e.text[:e.gapstart])
 	e.gapstart -= s
 	e.caret -= s
+	e.changed = e.changed || s > 0
 	e.dump()
 }
 
@@ -119,6 +131,7 @@ func (e *editBuffer) prepend(s string) {
 	e.moveGap(len(s))
 	copy(e.text[e.caret:], s)
 	e.gapstart += len(s)
+	e.changed = e.changed || len(s) > 0
 	e.dump()
 }
 

ui/text/editor.go

@@ -59,14 +59,16 @@ type EditorEvent interface {
 	isEditorEvent()
 }
 
-type Submit struct{}
+type ChangeEvent struct{}
+type SubmitEvent struct{}
 
 const (
 	blinksPerSecond  = 1
 	maxBlinkDuration = 10 * time.Second
 )
 
-func (s Submit) isEditorEvent() {}
+func (s ChangeEvent) isEditorEvent() {}
+func (s SubmitEvent) isEditorEvent() {}
 
 func (e *Editor) Next() (EditorEvent, bool) {
 	if cfg := *e.Config; cfg != e.oldCfg {
@@ -126,7 +128,7 @@ func (e *Editor) Next() (EditorEvent, bool) {
 			}
 			if e.Submit && (ke.Name == key.NameReturn || ke.Name == key.NameEnter) {
 				if !ke.Modifiers.Contain(key.ModShift) {
-					return Submit{}, true
+					return SubmitEvent{}, true
 				}
 			}
 			if e.command(ke) {
@@ -138,6 +140,9 @@ func (e *Editor) Next() (EditorEvent, bool) {
 			scrollTo = true
 			e.append(ke.Text)
 		}
+		if e.rr.Changed() {
+			return ChangeEvent{}, true
+		}
 	}
 	if sdist == 0 && scrollTo {
 		e.scrollToCaret()