Updated: Comment #0
Drupal 7 had the useful function drupal_parse_dependency to parse dependencies declared in the "example (>7.x-2.3)" format.
This was useful for contrib and was used in Libraries API as libraries use the same mechanism to declare dependencies.
In Drupal 8 the parsing is now done in the protected function \Drupal\Core\Extension\ModuleHandler::parseDependency(). The function is therefore inaccessible to contrib and would have to be copied. This is a regression in DX.
Since it is a utility function and does not access object state at all, tstoeckler proposes that it be made static as well. This is what we do with other utility methods (see \Drupal\(Core/Component)\Utility) and so should not offend OO purists any more than existing code. I am also open to moving this method to a separate utility class in case people find that this would be "tainting" ModuleHandler.
use Drupal\Core\Extension\ModuleHandler; ModuleHandler::parseDependency($dependency)
Note that there is currently no change notice for the removal of drupal_parse_dependency() :-/