Search results
Results From The WOW.Com Content Network
Switch statements function somewhat similarly to the if statement used in programming languages like C/C++, C#, Visual Basic .NET, Java and exist in most high-level imperative programming languages such as Pascal, Ada, C/C++, C#, [1]: 374–375 Visual Basic .NET, Java, [2]: 157–167 and in many other types of language, using such keywords as ...
Switch statements can allow compiler optimizations, such as lookup tables. In dynamic languages, the cases may not be limited to constant expressions, and might extend to pattern matching, as in the shell script example on the right, where the *) implements the default case as a glob matching any string.
Undefined parameter values are tricky: if the first positional parameter was not defined in the template call, then {{{1}}} will evaluate to the literal string "{{{1}}}" (i.e., the 7-character string containing three sets of curly braces around the number 1), which is a true value. (This problem exists for both named and positional parameters.)
Switch statements can allow compiler optimizations, such as lookup tables. In dynamic languages, the cases may not be limited to constant expressions, and might extend to pattern matching, as in the shell script example on the right, where the '*)' implements the default case as a regular expression matching any string.
Ignition uses an implementation of Python version 2.5 called Jython. Python script is used for component Event Handling. An example of this would be opening a popup window when a user clicks on a graphic object. Another common use are event scripts such as a timer that checks for alarms or a logon script.
A sample UML class and sequence diagram for the Command design pattern. [3]In the above UML class diagram, the Invoker class doesn't implement a request directly. Instead, Invoker refers to the Command interface to perform a request (command.execute()), which makes the Invoker independent of how the request is performed.
The most common example of the correct use of a switch within a loop is an inversion of control such as an event handler. In event handler loops, the sequence of events is not known at compile-time, so the repeated switch is both necessary and correct (see event-driven programming , event loop and event-driven finite state machine ).
The types of objects that can be iterated across (my_list in the example) are based on classes that inherit from the library class ITERABLE. The iteration form of the Eiffel loop can also be used as a boolean expression when the keyword loop is replaced by either all (effecting universal quantification ) or some (effecting existential ...