Re: macro for export-xml-rpc-method

On Wed, Jul 29, 2009 at 11:28 AM, jcb<[email protected]> wrote:
> The signature of export-xml-rpc-method is:
>
> (export-xml-rpc-method server '("method1" method1) :int :int :int)

So export-xml-rpc-method is a macro...

> (defparameter *my-methods*
> =A0 =A0'((("wg-base.foo" foo) :struct :string :int :string :string)
> =A0 =A0 =A0(("wg-base.bar" bar) :int :struct)
> =A0 =A0 =A0(("wg-base.barf" barf) :array)))
>
> I have fiddled unsuccessfully with the following:
>
> (defmacro call-export (server method-spec types-list)
> =A0 `(export-xml-rpc-method ,server ',method-spec ,@types-list))
>
> (defun export-my-methods (server)
> =A0(mapcar #'lambda (exported-method)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0(destructuring-bind (method &rest types) exported-method
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 (call-export server method types))) *my-methods*))

Right, the arguments (server etc) to call-export are not evaluated as
it is a macro. Move the construction of the macro forms to read time:

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defparameter *my-methods* ..))

#.(progn ,@(loop for (server method-spec types-list) in *my-methods*
                       collect (export-xml-rpc-method ,server
',method-spec ,@types-list)))

> Is there a way to do this or am I completely crazy for even trying...???

The read-time processor #. is the neat solution when you need to
generate a bunch of similar macro forms. It's much better than
something like (eval `(call-export ..)) because with #. the compiler
sees the expansion and can optimize it, register the source location
of the definition, etc.

- Willem