refactor i18n yaml to prevent overwriting parent non-English YAML with local English file: metanorma/isodoc#549

Author: opoudjis

Gemfile.devel

@@ -1 +1 @@
-gem "isodoc", git: "https://github.com/metanorma/isodoc", branch: "fix/recursive-prefix-container"
+gem "isodoc", git: "https://github.com/metanorma/isodoc", branch: "fix/i18n-yaml-inheritance"

lib/isodoc/ogc/i18n.rb

@@ -1,9 +1,14 @@
 module IsoDoc
   module Ogc
     class I18n < IsoDoc::I18n
+      def load_file(fname)
+        f = File.join(File.dirname(__FILE__), fname)
+        File.exist?(f) ? YAML.load_file(f) : {}
+      end
+
       def load_yaml1(lang, script)
-        y = YAML.load_file(File.join(File.dirname(__FILE__), "i18n-en.yaml"))
-        super.deep_merge(y)
+        y = load_file("i18n-#{yaml_lang(lang, script)}.yaml")
+        y.empty? ? load_file("i18n-en.yaml").merge(super) : super.deep_merge(y)
       end
     end
   end