Add add and sub

main.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 )
 
 func main() {
@@ -44,6 +45,14 @@ func listen(k *Keyboard, tp *TickPrinter, timer *Timer, stop func()) {
 	for {
 		key := <-k.Events
 		switch key {
+		case 'a':
+			timer.Add(time.Second)
+		case 'A':
+			timer.Add(time.Minute)
+		case 's':
+			timer.Sub(time.Second)
+		case 'S':
+			timer.Sub(time.Minute)
 		case 'p':
 			timer.TogglePause()
 		case 'z':

timer.go

@@ -89,3 +89,11 @@ func (t *Timer) Done() bool {
 func (t *Timer) String() string {
 	return t.Typed(t)
 }
+
+func (t *Timer) Add(d time.Duration) {
+	t.From = t.From.Add(d)
+}
+
+func (t *Timer) Sub(d time.Duration) {
+	t.Add(time.Duration(-1) * d)
+}