Apple is a PL/I dialect programming language created by General Motors Research Laboratories for their Control Data Corporation STAR-100 supercomputer.
An event variable can be associated with an external action, such as a keypress at the user's terminal, by a system call.
Events can also be marked complete with a SIGNAL statement, rather than the PL/I standard assignment to theCOMPLETION pseudovariable.
The REGISTER storage class and the INLINE builtin subroutine allow access to STAR hardware features.
[citation needed] The INLINE builtin subroutine inserts an arbitrary machine-language instruction into the compiled code.