Change history for XBlock

These are notable changes in XBlock.

0.4 - In Progress

  • Make Scope enums (UserScope.* and BlockScope.*) into Sentinels, rather than just ints, so that they can have more meaningful string representations.
  • Rename export_xml to add_xml_to_node, to more accurately capture the semantics.
  • Allowed Runtime implementations to customize loading from block_types to XBlock classes.

0.3 - 2014-01-09

  • Added services available through Runtime.service, once XBlocks have announced their desires with @XBlock.needs and @XBlock.wants.
  • The “i18n” service provides a gettext.Translations object for retrieving localized strings.
  • Make context an optional parameter for all views.
  • Add shortcut method to make rendering an XBlock’s view with its own runtime easier.
  • Change the user field of scopes to be three valued, rather than two. False becomes UserScope.NONE, True becomes UserScope.ONE, and UserScope.ALL is new, and represents data that is computed based on input from many users.
  • Rename ModelData to FieldData.
  • Rename ModelType to Field.
  • Split xblock.core into a number of smaller modules:
    • xblock.core: Defines XBlock.
    • xblock.fields: Defines ModelType and subclasses, ModelData, and metaclasses for classes with fields.
    • xblock.namespaces: Code for XBlock Namespaces only.
    • xblock.exceptions: exceptions used by all parts of the XBlock project.
  • Changed the interface for Runtime and ModelData so that they function as single objects that manage large numbers of XBlocks. Any method that operates on a block now takes that block as the first argument. Blocks, in turn, are responsible for storing the key values used by their field scopes.
  • Changed the interface for model_data objects passed to XBlocks from dict-like to the being cache-like (as was already used by KeyValueStore). This removes the need to support methods like iteration and length, which makes it easier to write new ModelDatas. Also added an actual ModelData base class to serve as the expected interface.