Inside a switch-endsw block case controls the execution of an alternative. If the condition of case is true, the following block is executed similar to an if-endif statement. The keyword break serves as end marker of case and leaves the switch block at the position of endsw. When break is omitted,
When the program's counter comes inside a switch construct to the keyword default, the following commands are processed in any case. A default statement can be finished by the keyword break, but does not have to.
if does conditional branching, if the first element of the argument is true. If has to be followed by an endif. Else is an optional part of if sequences.
switch allows the selection of one or more alternatives of many. Each alternative is introduced by a case statement. Similar to if-endif it controls, whether the following block is processed or not. The keyword break serves as end marker of case and leaves the switch block at the position of endsw.