> This has tanked my performance to the point where the tests for
> non-scalar types (vectors and hashes) time out on the package
> server, and thus fail.
The performance is probably because HashTable and Vector values can be
mutable, so Typed Racket needs to do extra work to protect them.
To test this, I cloned msgpack, removed `Vector` from the `Packable`
type, and changed `HashTable` to `Immutable-Hashtable`. Change here:
When I run the tests in test/pack/map.rkt, I see:
- 40 seconds with the types on master
- 13 seconds with immutable types
- 9 seconds on commit ac2b005 (before changing the types?)
I'm working on a pull request to add Immutable-Vector to Typed Racket.
That should be ready for the 6.12 release, and then msgpack can make
the `Packable` type immutable.
If that PR doesn't solve the performance problem, then I'd be happy to
keep looking for something that does.
> Another thing I noticed is that the predicate
> does not provide any proposition, if it succeeds the type checker is not
> informed that the object is of type `Packable`.
It *should* be possible to make the predicate a proposition by
changing the type of `packable?` to `(-> Any Boolean : Packable)`. But
I couldn't get this to type check.
Here's a simpler case that did work: http://pasterack.org/pastes/92542
But it's probably easier to just use `(define-predicate packable? Packable)`
> Another is that Typed Racket
> seems unable to narrow down the type of the result. Take a look at this
> > (require msgpack)
> > (define bs (call-with-output-bytes (λ (out) (pack 3 out))))
> > bs
> - : Bytes
> > (define v (call-with-input-bytes bs (λ (in) (unpack in))))
> > v
> - : Packable
> > (+ v 3)
> ; readline-input:8:3: Type Checker: type mismatch
> ; expected: Number
> ; given: Packable
> ; in: v
> ; [,bt for context]
> > (exact-integer? v)
> - : Boolean
> So the type checker can figure out that v is an integer, but it cannot treat
> it as one for addition.
The type checker doesn't know that `v` is an integer. It just knows
`v` is Packable.
You received this message because you are subscribed to the Google Groups
"Racket Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
For more options, visit https://groups.google.com/d/optout.