feat: added kwargs and flags to pass to plugins

internal/kwargs/kwargs.go

@@ -0,0 +1,34 @@
+package kwargs
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"git.towk2.me/towk/makeshift/internal/format"
+)
+
+const RESERVED_KEY = "kwargs"
+
+type KWArgs map[string]any
+
+func (kw KWArgs) String() string {
+	b, _ := json.Marshal(kw)
+	return string(b)
+}
+
+func (kw *KWArgs) Set(v string /* should be JSON object*/) error {
+	var (
+		newArgs KWArgs
+		err     error
+	)
+	err = format.Unmarshal([]byte(v), &newArgs, format.JSON)
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal value for %s: %w", kw.Type(), err)
+	}
+	*kw = newArgs
+	return nil
+}
+
+func (kw *KWArgs) Type() string {
+	return "KWArgs"
+}