A polymorphic calculus for views and object sharing (extended abstract)
Atsushi Ohori, Keishi Tajima · 1994
We present a typed polymorphic calculus that supports a general mechanism for view definition and object sharing among classes. In this calculus, a class can contain inclusion specifications of objects from other classes. Each such specification consists of a predicate determining the subset of objects to be included and a viewing function under which those included objects are manipulated. Both predicates and viewing functions can be any type consistent programs definable in the polymorphic calculus. Inclusion specifications among classes can be cyclic, allowing mutually recursive class definitions. These features achieve flexible view definitions and wide range of class organizations in a compact and elegant way. Moreover, the calculus provides a suitable set of operations for views and classes so that the programmer can manipulate views and classes just the same way as one deals with ordinary records and sets.