feat: support FocusIn/FocusOut

ansi/mode.go

@@ -80,6 +80,15 @@ const (
 	RequestMouseAllMotion = "\x1b[?1003$p"
 )
 
+// Report Focus is a mode that makes the terminal report focus-in and focus-out events.
+//
+// See: https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-FocusIn_FocusOut
+const (
+	EnableReportFocus  = "\x1b[?1004h"
+	DisableReportFocus = "\x1b[?1004l"
+	RequestReportFocus = "\x1b[?1004$p"
+)
+
 // SGR Mouse Extension is a mode that determines whether the mouse reports events
 // formatted with SGR parameters.
 //

exp/term/input/focus.go

@@ -0,0 +1,9 @@
+package input
+
+type (
+	FocusEvent struct{}
+	BlurEvent  struct{}
+)
+
+func (FocusEvent) String() string { return "focus" }
+func (BlurEvent) String() string  { return "blur" }

exp/term/input/focus_test.go

@@ -0,0 +1,25 @@
+package input
+
+import (
+	"testing"
+)
+
+func TestFocus(t *testing.T) {
+	_, e := ParseSequence([]byte("\x1b[I"))
+	switch e.(type) {
+	case FocusEvent:
+		// ok
+	default:
+		t.Error("invalid sequence")
+	}
+}
+
+func TestBlur(t *testing.T) {
+	_, e := ParseSequence([]byte("\x1b[O"))
+	switch e.(type) {
+	case BlurEvent:
+		// ok
+	default:
+		t.Error("invalid sequence")
+	}
+}

go.work.sum

@@ -38,6 +38,7 @@ golang.org/x/term v0.16.0/go.mod h1:yn7UURbUtPyrVJPGPq404EukNFxcm/foM+bV/bfcDsY=
 golang.org/x/term v0.19.0/go.mod h1:2CuTdWZ7KHSQwUzKva0cbMg6q2DMI3Mmxp+gKJbskEk=
 golang.org/x/term v0.21.0/go.mod h1:ooXLefLobQVslOqselCNF4SxFAaoS6KujMbsGzSDmX0=
 golang.org/x/term v0.22.0/go.mod h1:F3qCibpT5AMpCRfhfT53vVJwhLtIVHhB9XDjfFvnMI4=
+golang.org/x/term v0.23.0/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/tools v0.1.12 h1:VveCTK38A2rkS8ZqFY25HIDFscX5X9OoEhJd3quQmXU=

input/focus.go

@@ -0,0 +1,13 @@
+package input
+
+// FocusEvent represents a focus event.
+type FocusEvent struct{}
+
+// String implements fmt.Stringer.
+func (FocusEvent) String() string { return "focus" }
+
+// BlurEvent represents a blur event.
+type BlurEvent struct{}
+
+// String implements fmt.Stringer.
+func (BlurEvent) String() string { return "blur" }

input/focus_test.go

@@ -0,0 +1,25 @@
+package input
+
+import (
+	"testing"
+)
+
+func TestFocus(t *testing.T) {
+	_, e := ParseSequence([]byte("\x1b[I"))
+	switch e.(type) {
+	case FocusEvent:
+		// ok
+	default:
+		t.Error("invalid sequence")
+	}
+}
+
+func TestBlur(t *testing.T) {
+	_, e := ParseSequence([]byte("\x1b[O"))
+	switch e.(type) {
+	case BlurEvent:
+		// ok
+	default:
+		t.Error("invalid sequence")
+	}
+}

input/key_test.go

@@ -101,6 +101,19 @@ func buildBaseSeqTests() []seqTest {
 func TestParseSequence(t *testing.T) {
 	td := buildBaseSeqTests()
 	td = append(td,
+		// focus/blur
+		seqTest{
+			[]byte{'\x1b', '[', 'I'},
+			[]Event{
+				FocusEvent{},
+			},
+		},
+		seqTest{
+			[]byte{'\x1b', '[', 'O'},
+			[]Event{
+				BlurEvent{},
+			},
+		},
 		// Mouse event.
 		seqTest{
 			[]byte{'\x1b', '[', 'M', byte(32) + 0b0100_0000, byte(65), byte(49)},

input/parse.go

@@ -290,6 +290,10 @@ func parseCsi(b []byte) (int, Event) {
 	}
 
 	switch cmd := csi.Command(); cmd {
+	case 'I':
+		return i, FocusEvent{}
+	case 'O':
+		return i, BlurEvent{}
 	case 'R':
 		// Cursor position report OR modified F3
 		if paramsLen == 0 {