Add support for typed data selection

The Needs Review Queue Bot → tested this issue. It either no longer applies to Drupal core, or fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

While this certainly needs to be re-rolled after 8 years, it would be more productive at this point to get some feedback from core committers or other interested parties to hear if there is even any desire or interest to add this feature. Re-rolling at this point is probably just wasted work if no-one is going to even look at it ...

I agree, rerolling is not helpful here. Added framework manager review tag here - I think that is the right one.

The Needs Review Queue Bot → tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

per #58

Token is used for a lot of things it shouldn't be, so adding this seems reasonable if we're able to consolidate it properly.

I think there are two main things:

1. This needs an issue summary update. What is the next step after this issue? Are there existing places in core it can already be used? How will it replace 90% of token API?

2. The $selectors parameter is very loose, at the least it could use some examples in the phpdoc.

+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -442,4 +442,55 @@ public function clearCachedDefinitions() {
+   *
+   * @param \Drupal\Core\TypedData\ComplexDataInterface|\Drupal\Core\TypedData\ListInterface $data
+   *   The data to select a descendent property from.
+   * @param array $selectors
+   *   An array of strings that identify child properties. These strings can be
+   *   array keys, or names of object properties, for instance.
+   *

The docs should give some examples of selectors.