Only one event can be triggered from the start state and canceling the start is not
allowed. If canceling is de?¬?ned in the application design (i.e., Cancel is pressed
FIGURE 8.4 Metamodel of the language
LANGUAGE FOR APPLICATION MODELING 171
in a dialog after a start stage) the generator produces an application exit code
(see Section 8.5.2 for details).
. There can exist only one start object per application design, but if the
application consists of multiple views, each view can have its own start
object.
. The optional function name was declared unique to enable unique Python
function naming during code generation.
. The return variable used in most modeling elements was made unique to
support variable naming and to allow reuse of the entered values within the
application.
Rules that dealt with the possible navigation actions, such as accept, opening a
menu, and cancel, were de?¬?ned on the connections between the modeling concepts.
Some of the rules are as follows:
. For some language elements, normal navigation ?¬‚ow was de?¬?ned to allow only
one target element. For example, in S60, after showing a noti?¬?er for a couple
of seconds, only one UI element or phone service can be triggered.
Accordingly, the metamodel included a rule that allows only one ?¬‚ow from the
Note element.
. The exception to the above navigation rule was allowing multiple targets for
List and Pop-up dialogs and for accessing menus from UI controls.
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