Notes:
Current trend: simplification/unification of low-level types:
Perl blurs int/double
Scheme & Ruby blurs int/bigint
Name vs structural equivalence is less a problem when mostly everything is abstract
History:
Records: Cobol (already instanciated)
Lists: Lisp
Pointers: PL/I
User defined: Algol 68
Abstract types: Simula 67