On Apr 27, 2010, at 3:20 AM, Mark Engelberg wrote:
Watching Stuart's tutorial, it looks like the automatic factory
functions for deftypes have gone away (I'm still working with Clojure
1.1, so haven't had a chance to try the latest changes for myself).
I'm going to miss that feature, especially for defrecord, which is now
the "common case" construct.
I understand that you can always do "Foo." to construct a Foo record,
but these constructors don't act as full-fledged functions, right?
Honestly, for me the main issue is just that subjectively, it is less
satisfying to create a Clojure data structure and end up with
something that you construct with Java interop syntax. I'd like
Clojure data structures to look and feel "Clojurish" not "Javaish"
(yes, I know that Clojure is built with interop in mind, so
technically, anything Javaish is also Clojurish, but I still feel a
difference).
I agree. I asked for suggestions for the factory fn in #clojure, but
got some pushback against introducing things in the namespace. I'm
still open to suggestions, here are the issues:
The generated type name is now imported, so at the very least the
factory fn can't have the same name as the class. Alternatives are
create-Foo etc.
Some have asked for parameterized factories:
(record Foo ...) or (record ::Foo ...)
These cannot be made as fast as direct factories. Also, they may be
used for key/value initialization:
(record ::Foo :field1 v1 :field2 v2 ...)
As soon as people want bodies for the factories, in order to do
argument transformation/validation/defaulting, a generated factory is
in the way.
We left it at: If you really want a factory you can always write one,
let's see if people do.
Rich
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