IOError vs. Exception vs. IOException

Wolfgang Jeltsch
Sun, 17 Nov 2002 00:15:33 +0100

On Saturday, 2002-11-16, 05:24, CET, Alastair Reid wrote:
> [...]

> The set of exceptions is already undefined.  The IOError type is
> deliberately abstract (i.e., you can't see the constructors) so that th=
e set
> of exceptions can be extended.  (It would have been more convenient if =
> could see the constructors so that you could use pattern matching but m=
> it extensible won out over convenience.)


AFAICS, there is no discrepancy between making IOError extensible and=20
revealing constructors. A specification could guarantee that IOError has=20
certain data constructors while not forbidding that it has more than thes=

> [...]