There are two areas in which name conflicts occur:
Variables that are defined within different scopes can have the same name. For example, a global variable can have the same name as a local or instance variable. The compiler warns you of these conflicts, but you do not have to change the names.
A descendent object has functions and events that are inherited from the ancestor and have the same names.
If you need to refer to a hidden variable or an ancestor’s event or function, you can use dot notation qualifiers or the scope operator.
If an instance variable has the same name as a local, shared, or global variable, qualify the instance variable with its object’s name:
objectname.instancevariable
If a local variable and an instance variable of a window are both named birthdate, then qualify the instance variable:
w_main.birthdate
If a window script defines a local variable x, the name conflicts with the X property of the window. Use a qualifier for the X property. This statement compares the two:
IF x > w_main.X THEN
If a global variable has the same name as a local or shared variable, you can access the global variable with the scope operator (::) as follows:
::globalvariable
This expression compares a local variable with a global variable, both named total:
IF total < ::total THEN ...
Use prefixes to avoid naming conflicts
If your naming conventions include prefixes that identify
the scope of the variable, then variables of different scopes always
have different names and there are no conflicts.
For more information about the search order that determines how name conflicts are resolved, see the chapters about declarations and calling functions and events in the PowerScript Reference.
When you change the script for a function that is inherited, you override the ancestor version of the function. For events, you can choose to override or extend the ancestor event script in the painter.
You can use the scope operator to call the ancestor version of an overridden function or event. The ancestor class name, not a variable, precedes the colons:
result = w_ancestor:: FUNCTION of_func(arg1, arg2)
You can use the Super pronoun instead of naming an ancestor class. Super refers to the object’s immediate ancestor:
result = Super:: EVENT ue_process()
In good object-oriented design, you would not call ancestor scripts for other objects. It is best to restrict this type of call to the current object’s immediate ancestor using Super.
For how to capture the return value of an ancestor script, see “Return values from ancestor scripts”.
When you have several functions of the same name for the same object, the function name is considered to be overloaded. PowerBuilder determines which version of the function to call by comparing the signatures of the function definitions with the signature of the function call. The signature includes the function name, argument list, and return value.
