Improved docs

README.md

@@ -9,13 +9,15 @@ GNU gettext utilities for Go.
 
 #Features
 
-- Implements GNU gettext support in native Go. 
-- It works with UTF-8 encoding as it's the default for Go language. 
-- Supports pluralization rules.
-- Ready to use inside Go templates.
-- Safe for concurrent use accross multiple goroutines.
+- Implements GNU gettext support in native Go.
+- Safe for concurrent use accross multiple goroutines. 
+- It works with UTF-8 encoding as it's the default for Go language.
+- Unit tests available 
 - Language codes are automatically simplified from the form "en_UK" to "en" if the formed isn't available.
-- Unit tests available
+- Ready to use inside Go templates.
+- Support for pluralization rules.
+- Support for variables inside translation strings using the Go's [fmt package syntax](https://golang.org/pkg/fmt/)
+
 
 
 # Installation 
@@ -39,6 +41,46 @@ go get github.com/leonelquinteros/gotext
 Refer to the Godoc package documentation at (https://godoc.org/github.com/leonelquinteros/gotext)
 
 
+# Locales directories structure
+
+The package will asume a directories structure starting with a base path that will be provided to the package configuration 
+or to object constructors depending on the use, but either will use the same convention to lookup inside the base path. 
+
+Inside the base directory where will be the language directories named using the language and country 2-letter codes (en_US, es_AR, ...). 
+All package functions can lookup after the simplified version for each language in case the full code isn't present but the more general language code exists. 
+So if the language set is "en_UK", but there is no directory named after that code and there is a directory named "en", 
+all package functions will be able to resolve this generalization and provide translations for the more general library.  
+
+The language codes are assumed to be [ISO 639-1](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) codes (2-letter codes). 
+That said, most functions will work with any coding standard as long the directory name matches the language code set on the configuration. 
+
+A normal library directory structure may look like: 
+
+```
+/path/to/locales
+/path/to/locales/en_US
+/path/to/locales/en_US/default.po
+/path/to/locales/en_US/extras.po
+/path/to/locales/en_UK
+/path/to/locales/en_UK/default.po
+/path/to/locales/en_UK/extras.po
+/path/to/locales/en_AU
+/path/to/locales/en_AU/default.po
+/path/to/locales/en_AU/extras.po
+/path/to/locales/es
+/path/to/locales/es/default.po
+/path/to/locales/es/extras.po
+/path/to/locales/es_ES
+/path/to/locales/es_ES/default.po
+/path/to/locales/es_ES/extras.po
+/path/to/locales/fr
+/path/to/locales/fr/default.po
+/path/to/locales/fr/extras.po
+``` 
+
+And so on...
+
+
 
 # About translation function names