cjl@iuvax.UUCP (12/04/83)
#N:iuvax:8600004:000:915
iuvax!cjl Dec 3 18:22:00 1983
The manual I have "Progamming in Modula-2" seems to suggest that
open array is a descent feature like Ada's unconstraint arrays. But I
think the idea of "open array" should be classified as a low level
feature for the following reasons :
(1) It actually models the sequence data structure. The compatibility
to arrays of any index type belongs to the structure compatibility
domain not the strong type idea.
(2) Even two data sets having the same data structures, they don't
have to have the same type names because we might want to classify
them as different abstract data types.
(3) The use of "open array" is to allow sharing of array handling
procedures. It is an implementation issue not a high level concept.
For the above reasons, Modula-2 actually offers a better solution
than Ada's unconstraint arrays where the problem may still exist if we
use different type names.