On Wed, Jul 7, 2010 at 12:49 PM, Cameron <cpuls...@gmail.com> wrote:

> Hello all! Today, I've either discovered a bug, or I've discovered a
> flaw in my understanding of macros. Most likely the latter :-) Could
> anyone set me straight?
>
> While this is not the macro I was trying to write, it falls over in
> the same place.
>
> (user=> (defmacro foo [& xs] `(map identity ~xs))
> #'user/foo
> user=> (foo 1 2)

java.lang.ClassCastException: java.lang.Integer cannot be cast to
> clojure.lang.IFn (NO_SOURCE_FILE:0)
>

You're splicing in the list (1 2). 1 is not function, thus the error.


> However, this does work (though it doesn't feel idiomatic).
>
> user=> (defmacro foo [& xs] `(map identity [...@xs]))
> #'user/foo
> user=> (foo 1 2)
> (1 2)
>

Looks pretty idiomatic to me :)

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