Providing a :default implementation for multimethods is a very common
and useful technique, but it is really useful only for multimethods
that dispatch on a single argument. What I am looking for is an
equivalent technique for multiple-argument dispatch.
Suppose you have a multimethod + of
On Mar 20, 10:56 am, Konrad Hinsen konrad.hin...@laposte.net wrote:
Providing a :default implementation for multimethods is a very common
and useful technique, but it is really useful only for multimethods
that dispatch on a single argument.
I disagree about that. No dispatch value,
You could use multiple multi-methods:
user= (defmulti plus-int (fn [x y] (type y)))
#'user/plus-int
user= (defmethod plus-int :default [x y] (println the first is an int))
#MultiFn clojure.lang.mult...@11992cc
user= (defmethod plus-int java.lang.Double [x y] (println one of each))
#MultiFn
It's also not as maintainable as using a single multi-method.
Like I said, not pretty, but it works.
Paul
On Fri, Mar 20, 2009 at 11:38 AM, David Nolen dnolen.li...@gmail.comwrote:
This works well as long as you don't mind the perf hit for the second
dispatch :)
On Fri, Mar 20, 2009 at
On Mar 20, 2009, at 16:35, Paul Stadig wrote:
You could use multiple multi-methods:
...
Not pretty, as you said, but also not quite the same in behaviour as
a single multimethod dispatching on both arguments. Multiple dispatch
can be made symmetric in the arguments, whereas a chain of
On Mar 20, 2009, at 16:18, Rich Hickey wrote:
Providing a :default implementation for multimethods is a very common
and useful technique, but it is really useful only for multimethods
that dispatch on a single argument.
I disagree about that. No dispatch value, composite or not, is still a
