Thanks everyone for your answers. I must say I'm quite mystified as to why
Stuart's version works.
I ended up defining a function that has the same signature as the protocol,
and whose first argument wraps a function that contains the appropriate
code.
Vincent
On Wednesday, 5 June 2013
I’m trying to write a macro that defines a protocol and a function that,
when called, returns an implementation of that protocol.
I’ve reduced the code to the following example:
(defmacro create-protocol [protocol implementation]
(let [[protocol-name signature] protocol]
`(do
Hi Vincent,
`defprotocol` is a top-level form, not really meant to be mixed with
value-returning expressions like `fn`. Protocols are always global because
of how they compile into Java interfaces.
Here's one way to make it work, by defining a symbol instead of returning a
function:
*`defprotocol` is a top-level form...*
This is interesting, and it's something I've wondered about. As far as I
can tell, there's really no distinction between top-level forms and other
forms, for example this is legal and works:
(defn define-my-functions []
(defn test-1 []
1)
(defn
On Wed, Jun 5, 2013 at 7:35 PM, Colin Fleming
colin.mailingl...@gmail.comwrote:
Given this, are there any forms that are genuinely top-level from the
compiler's point of view?
It's never explicitly enforced, just a consequence of how the compiler
creates and loads Java classes. Generally,
Legal but comparable to a hidden side effect with all the pitfalls that can
derive
from this.
It's not a compiler issue, more a discipline issue.
Having a helper macro like Stuart suggest is acceptable to me
if it's called at top level, it's always done. There's less ambiguity.
Using def/defn
