For speech rate in settings up/down move by 10, left/right move by 1. Easier to get settings right without having to hold doown the arrow keys lol.

internal/interaction/form.go

@@ -37,6 +37,7 @@ type Control struct {
 	Checked        bool
 	Number         float64
 	Min, Max, Step float64
+	UpDownStep     float64 // Zero uses the default step of 1 for Up and Down.
 	Text           string
 	Items          []string
 	Selected       int

internal/interaction/session.go

@@ -54,6 +54,14 @@ func New_session(form Form) (*Session, error) {
 				return nil, fmt.Errorf("invalid control %q", control.ID)
 			}
 			controlIDs[control.ID] = true
+			if control.Kind == Number {
+				if control.UpDownStep == 0 {
+					control.UpDownStep = 1
+				}
+				if math.IsNaN(control.UpDownStep) || math.IsInf(control.UpDownStep, 0) || control.UpDownStep < 0 {
+					return nil, fmt.Errorf("invalid vertical step %q", control.ID)
+				}
+			}
 			if control.Kind == Number && (math.IsNaN(control.Number) || math.IsInf(control.Number, 0) || math.IsNaN(control.Min) || math.IsInf(control.Min, 0) || math.IsNaN(control.Max) || math.IsInf(control.Max, 0) || math.IsNaN(control.Step) || math.IsInf(control.Step, 0) || control.Min > control.Max || control.Step <= 0 || control.Number < control.Min || control.Number > control.Max) {
 				return nil, fmt.Errorf("invalid range %q", control.ID)
 			}
@@ -244,9 +252,9 @@ func (s *Session) Handle(key Key) Result {
 		delta := 0.0
 		switch key.Name {
 		case "up":
-			delta = 1
+			delta = control.UpDownStep
 		case "down":
-			delta = -1
+			delta = -control.UpDownStep
 		case "right":
 			delta = control.Step
 		case "left":

internal/interaction/session_test.go

@@ -17,7 +17,20 @@
 
 package interaction
 
-import "testing"
+import (
+	"math"
+	"testing"
+)
+
+func TestInvalidNumberUpDownStepRejected(t *testing.T) {
+	for _, step := range []float64{-1, math.NaN(), math.Inf(1), math.Inf(-1)} {
+		form := test_form()
+		form.Tabs[0].Controls[1].UpDownStep = step
+		if _, err := New_session(form); err == nil {
+			t.Fatalf("invalid Up/Down step %v accepted", step)
+		}
+	}
+}
 
 func test_form() Form {
 	return Form{Type: TabForm, Title: "Settings", Tabs: []Tab{