Description
Symfony's way to handle the parsing of types for environment variables in configuration files is very useful.
Unfortunatly, in order to use it, i must first create a container object.

I think the Environment Variable Processors could be made into a standalone component in order to use it in any PHP projects.

Example
I created a composer plugin to automate a CMS installation, i need to allow the user to define env vars that sould be copied to the CMS configuration file.

The user can write his vars in the composer.json "extra" configuration.

I just need a way to know what type of vars i am to expect.

composer.json :

... 
"extra": {
    "my-plugin": {
      "config-extra-vars": {
        "EXEMPLE": "env(int:TEST)"
      }
    }
...