On Wed, Sep 9, 2009 at 3:23 PM, Tom Lane<t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> What we need is a system where base types are represented >> by an OID, but derived types (list and functional types) are built up >> using type constructors that take other types as arguments. > > This is SQL, not Haskell. What you suggest seems about two orders of > magnitude more complex than real-world applications could justify. > > (so where is pl/haskell, anyway?)
There are languages much less obscure than Haskell that support passing functions as arguments to other functions, such as C. While C doesn't support user-defined type constructors, it does support one built-in type constructor - you can declare a function argument as taking arbitrary argument types and returning an arbitrary type. C++ supports user-defined type constructors via the template mechanism. The scripting languages generally do not guarantee type-safety for functions passed as arguments, but they do let you pass them. However, I can't really imagine how we could get away with such a system in SQL, due to security concerns. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
