Unify YAML translation extraction, and allow extension by contrib.

This looks good as a first step, it does not yet support integration with contrib solutions though. What do you think how would we do the reading of those files? It sounds like it would be similar to how you read all the schema files first and then the parsing of the config files. Here the "schema" files are the YAML pattern files (not happy for the name but have no better idea :D).

The patch itself looks amazing, so committed this patch for now. What we need though is a translatables yaml file in the D8 module and some of our own defined YAML file eg. potx_test_8.potx_test_strings.yml or something from where to test the extraction, so we test the discovery of the translatables definition and that it works.

1. +++ b/potx.inc
   @@ -1855,10 +1855,50 @@ function _potx_find_translation_annotations($file, $save_callback) {
   + *     # a sequence of translatable keys in the matched YAML files.
   ...
   + *         # an optional key, used as context for the translatable string.
   

   Start with uppercase.

2. +++ b/potx.inc
   @@ -1855,10 +1855,50 @@ function _potx_find_translation_annotations($file, $save_callback) {
   + * @endcode
   + * @param string $path
   

   Add newline between endcode and param.

3. +++ b/tests/potx.test
   @@ -338,6 +338,16 @@ class PotxTestCase extends DrupalWebTestCase {
   +    $this->parseFile(drupal_get_path('module', 'potx') . '/tests/potx_test_8/potx_test_8.test.yml', POTX_API_8);
   

   Test file was not in the patch :)

Yay, thanks, that looks great. Fixed the whitespace errors in potx_test_8.test.yml on commit.

Ported to 7.x-3.x as it has been branched directly from 6.x-3.x

The documentation is a little unclear to me. Say I have the following *.payment.status.yml YAML structure, how would I make the label and description items translatable?

payment_authorization_failed:
  label: Authorization failed
  parent_id: payment_failed
payment_authorized:
  description: The payment has been authorized by the payer, and the funds are waiting to be transferred.
  label: Authorized
  parent_id: payment_no_money_transferred

I tried this, but despite the fact that POTX scanned the YAML files, the strings did not end up in the pot file:

*.payment.status.yml:
  - label
  - description

Are you sure potx considers your declaration of translatable things? I suspect that may be the problem.

#2357365: Followup: Keep YAML translation patterns throughout the request turned out to be the root cause.