feat: input and output file

params.go

@@ -3,14 +3,16 @@ package main
 import (
 	"flag"
 	"fmt"
+	"os"
 )
 
 func parseParams(meta TemplateMeta) (ctx TemplateContext, err error) {
 	result := make(map[string]*string)
+	fs := flag.NewFlagSet("params", flag.ExitOnError)
 	for key, spec := range meta.Params {
-		result[key] = flag.String(key, spec.Default, key)
+		result[key] = fs.String(key, spec.Default, key)
 	}
-	flag.Parse()
+	fs.Parse(os.Args[2:])
 	ctx = make(TemplateContext)
 	for key, spec := range meta.Params {
 		if spec.Required && *result[key] == "" {