Real polymorphic structs in Franca

[Klaus Birken]

Hi all,

there are two RFC issues (Request-For-Comments, #19 and #39) on the Franca issue list which are related to inheritance hierarchies of Franca structs and their polymorphic usage as method/broadcast arguments. In #39, a solution is proposed which requires a slight extension of Franca IDL syntax. 

Link to issue #39.

Please review these issues until the RFC deadline of CW23 (first week of June). If you want to provide a better solution or other kind of feedback, pls do so. We are glad for an extended discussion in order to find the optimal solution.

Regards,

Klaus

[Klaus Birken]

Hi all,

the RFC is closed (no vetos). The feature has been implemented as proposed in the ticket ("polymorphic"-keyword for structs). See issue 39 for more information. It will be part of Franca release 0.8.8.

Regarding issue 19, the transformation Franca->DBus has been adapted to handle polymorphic structs properly: If a struct (or its derived structs) is marked as polymorphic, the representation in D-Bus Introspection format will be "(iv)". I.e., it is represented as an integer tag (typically defined by some enumeration) and the actual data. The data has to be defined as variant type, because by looking at just one interface it cannot be decided which derived struct will be actual be communicated. This change will also be part of Franca release 0.8.8.

Regards,

Klaus