Let a declared datatype win over a column read, count a repeat as written, refuse null alone on stdin and a second leading slash, and hand NewTemplate stdin as sent

render.go

@@ -16,7 +16,10 @@ import (
 func (f *Generator) Fake(path string) (string, error) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
-	path = grammar.CallerPath(path)
+	path, err := grammar.CallerPath(path)
+	if err != nil {
+		return "", fmt.Errorf("fejkdata: %w", err)
+	}
 	segments, err := grammar.SplitPath(path)
 	if err != nil {
 		return "", fmt.Errorf("fejkdata: %w", err)