invocation: round of cleanups/fixes

token/internal/parse/parse.go

@@ -0,0 +1,22 @@
+package parse
+
+import (
+	"time"
+
+	"github.com/ucan-wg/go-ucan/did"
+)
+
+func OptionalDID(s *string) (did.DID, error) {
+	if s == nil {
+		return did.Undef, nil
+	}
+	return did.Parse(*s)
+}
+
+func OptionalTimestamp(sec *int64) *time.Time {
+	if sec == nil {
+		return nil
+	}
+	t := time.Unix(*sec, 0)
+	return &t
+}