On Nov 12, 1:10 pm, Rich Hickey <richhic...@gmail.com> wrote:
> An early version of the code for a few important new language
> features, datatypes[1] and protocols[2] is now available in the 'new'
> branch[3]. Note also that the build system[4] has builds of the new
> branch, and that the new branch works with current contrib.
>
> If you have the time and inclination, please try them out. Feedback is
> particularly welcome as they are being refined.
>
> Thanks,
>
> Rich
I've had very good experiences so far - I really like the modeling
aspects of this.
Two comments.
First is a bug.
Using newest commit of new: 75cd05080f7260c54007d7728fb280ae53b56f63
Clojure 1.1.0-alpha-SNAPSHOT
user=> (deftype Foo [x])
#'user/Foo
user=> (defprotocol P (fun [x]))
P
user=> (extend ::Foo P {:fun (fn [x] x)})
nil
user=> (fun (Foo 42))
#:Foo{:x 42}
user=> (def f1 (Foo 42))
#'user/f1
user=> f1
#:Foo{:x 42}
user=> (def f2 (fun f1))
java.lang.IllegalAccessError (NO_SOURCE_FILE:7)
user=>
The error occurs if I try to bind the result of a protocol function to
a var.
Second is a feature request:
Map-based initializers and Default values for deftype.
Example:
user=> (deftype TransitionPolicy [fail-count timeout])
#'user/TransitionPolicy
user=> (def p (TransitionPolicy {:fail-count 5 :timeout 5000}))
;; I'd like
'user/p
user=> p
#:TransitionPolicy{:fail-count 5, :timeout 5000}
user=>
Now defaults:
user=> (deftype TransitionPolicy [fail-count :def 5 timeout :def
5000])
;;I'd like
#'user/TransitionPolicy
user=> (TransitionPolicy :fail-count 5)
#:TransitionPolicy{:fail-count {:fail-count 10}, :timeout 5000}
user=> (TransitionPolicy)
#:TransitionPolicy{:fail-count 5, :timeout 5000}
I know I can easily construct functions that realize these maps and
default initializers, but it would be nice to have Out-of-the-box if
it doesn't complicate the design.
Cheers,
/Karl
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