diff --git a/documentation/current/method/void-safe-programming-eiffel/creating-new-void-safe-project.wiki b/documentation/current/method/void-safe-programming-eiffel/creating-new-void-safe-project.wiki index 02214cc1..4ec77f13 100644 --- a/documentation/current/method/void-safe-programming-eiffel/creating-new-void-safe-project.wiki +++ b/documentation/current/method/void-safe-programming-eiffel/creating-new-void-safe-project.wiki @@ -226,11 +226,11 @@ As with the other examples of the '''attached syntax''', it is no longer necessa ==More about CAPs== -You might wonder about the use of a CAP using a check like this: +You might wonder about the use of a CAP which employs a check instruction like this: my_detachable_any: detachable ANY - + ... my_attached_any: ANY local l_result: like my_detachable_any diff --git a/documentation/current/solutions/gui-building/eiffelvision-2/converting-eiffelvision-2-systems-void-safety.wiki b/documentation/current/solutions/gui-building/eiffelvision-2/converting-eiffelvision-2-systems-void-safety.wiki new file mode 100644 index 00000000..88d7adc7 --- /dev/null +++ b/documentation/current/solutions/gui-building/eiffelvision-2/converting-eiffelvision-2-systems-void-safety.wiki @@ -0,0 +1,83 @@ +[[Property:title|Converting EiffelVision 2 Systems to Void Safety]] +[[Property:link_title|Converting EiffelVision 2 Systems to Void-Safety]] +[[Property:weight|1]] +[[Property:uuid|96e01318-700b-da6e-42d1-14fee219daf5]] +Converting EiffelVision 2 System to Void Safety + +In order to convert systems that employ EiffelVision 2 (Vision2) to void-safety, some adjustments may be needed depending on its usage. This document describes the various usage scenarios of Vision2 that will need converting to adhere to void-safety. + +Inheritance purely from an Interface Class + +If you have classes that inherit from a Vision2 interface class such as EV_DRAWING_AREA, the first change that has to be made is to alter 'initialize' so that any types that are attached (ie: types that remain non-void throughout the lifetime of its housing parent object) are initialized via 'create_interface_objects', this needs to be redefined if the type from Vision2 is instantiable, if not then it may need to be made effective (such as inheritance directly from EV_ANY). It is important that any attached types in the interface class are instantiated in `create_interface_objects' and these objects are initialized via 'initialize'. Attached types should not be instantiated in `initialize' due to the bridge pattern implementation and initialization of these types in `create_interface_objects' MUST be performed via 'initialize', otherwise unexpected behavior may occur as the bridge pattern has not been fully set up at this point in time. + +Example from EV_TIMEOUT + + +feature {NONE} -- Implementation + +create_interface_objects +-- +do +create actions +end + +create_implementation +-- Create implementation of button. +do +create {EV_TIMEOUT_IMP} implementation.make +end + + +Inheritance from an Implementation Interface Class with associating interface class + +If you have an existing, custom platform dependent implementation, there are a few more changes needed than what was required for the interface class. + +For the interface class changes, now the interface object is passed to the implementation after creation, via `assign_interface', this means that `make' no longer takes an argument. This also means that to adhere to void-safety all of the types are now created and initialized via the creation routine of the implementation object. + + +An example from the conversion of Windows implementation of EV_BUTTON_IMP. + + + make (an_interface: like interface) + -- Create `Current' with interface `an_interface'. + do + base_make (an_interface) + wel_make (default_parent, "", 0, 0, 0, 0, 0) + extra_width := 20 + text_alignment := default_alignment + -- Retrieve the theme for the button. + open_theme := application_imp.theme_drawer.open_theme_data (wel_item, "Button") + end + + initialize + -- Initialize `Current'. + do + Precursor {EV_PRIMITIVE_IMP} + set_default_font + end + + interface: EV_BUTTON; + +would become: + + make + -- Initialize `Current'. + do + wel_make (default_parent, "", 0, 0, 0, 0, 0) + extra_width := 20 + text_alignment := default_alignment + -- Retrieve the theme for the button. + open_theme := application_imp.theme_drawer.open_theme_data (wel_item, "Button") + Precursor {EV_PRIMITIVE_IMP} + set_default_font + end + + interface: detachable EV_BUTTON note option: stable attribute end; + +The following steps are needed during the conversion: + +- The attribute 'interface' needs to be made a stable attribute +- Copy any initialization of the widget from 'make' to 'initialize' excluding `base_make' setup. Any initialization code that relies on `interface' would have to be rewritten so that this gets passed to new creation routine that in turn calls the original `make'. See EV_PRINT_PROJECTOR_IMP on Windows `make_with_context' for an example of this. +- Remove `make', rename `initialize' to `make', make sure that any calls to Precursor do not override any settings set in 'initialize', the ordering may need to be changed in order to make the code void-safe so. See EV_POPUP_WINDOW_IMP.make (Windows implementation) where the setting of 'user_can_resize' is performed after the Precursor call so that is doesn't get overriden. + +