On Sep 7, Jay McCarthy wrote:
On Tue, Sep 7, 2010 at 5:54 AM, Sam Tobin-Hochstadt sa...@ccs.neu.edu wrote:
On Mon, Sep 6, 2010 at 10:28 PM, Eli Barzilay e...@barzilay.org wrote:
On Sep 6, Sam Tobin-Hochstadt wrote:
On Sun, Sep 5, 2010 at 5:30 PM, Eli Barzilay e...@barzilay.org wrote:
I think that this is the type for `file-or-directory-modify-seconds':
(case-lambda
[String - Exact-Nonnegative-Integer]
[String (Option Exact-Nonnegative-Integer)
- (U Exact-Nonnegative-Integer Void)]
[String (Option Exact-Nonnegative-Integer) (- Any)
- Any])
Probably you want something more specific that handles the [String
Integer] and [String False] cases separately.
Yeah, but that's the part that I can never remember. This:
(U (String - Exact-Nonnegative-Integer)
(String False - Exact-Nonnegative-Integer)
(String Exact-Nonnegative-Integer - Void)
(String (Option Exact-Nonnegative-Integer) (- Any) - Any))
is more precise, but IIRC, it's not equivalent to the above -- ?
Why does everyone always want to use union for this?
I vaguely remembered that unions don't work for functions, and
therefore didn't use one (also that ? is exactly about it.)
Everything you wrote there is correct, except that `U' should be
`case-lambda'.
There is something to be said for making the things that everyone
writes first be the thing they should write. It is natural to me to
think of a function with multiple arrow types as a union of some
arrow types. Would it be so hard for Typed Racket to see a union of
all arrows and just consider that the same as case-lambda? Is that
wrong? If it is fundamentally wrong, some better form of
explanation in the docs seem warranted.
+1 to all of that. [Why does everyone reminds me of a teacher who
had about 112 students out of a class of 120 students fail a course --
and concluded that it was a very weak class.]
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!
_
For list-related administrative tasks:
http://lists.racket-lang.org/listinfo/dev
