Generate a trimmed, formatted version of a text field value.

If the end of the summary is not indicated using the < !--break--> delimiter (remove the space after the first angle bracket) then we generate the summary automatically, trying to end it at a sensible place such as the end of a paragraph, a line break, or the end of a sentence (in that order of preference).

https://api.drupal.org/api/drupal/modules!field!modules!text!text.modul…