Re: Optional and Default Parameters

[Jonathan Rees <Rees@YALE.ARPA>]

Sorry, I should have been more verbose in my laast message.  First,
I generally don't approve of keywords, so "optionals" would go into
T with some other syntax.  Second, I meant that an *efficient*
implementation would a lot of work - a macro for defaulting optional
arguments would be easy to do right now, but would not be acceptable
in places as performance-sensitive as the I/O system.  Said inefficiency
comes from the fact that "rest-arguments" currently cons lists
regardless of what's being done with them, and this is precisely what
would be non-trivial to change.