Hello again,
This has solved the issue:
(let [cache (atom {})
cache-eval (fn [obj]
(when-not (contains? @cache obj)
(reset! cache (assoc @cache obj (eval obj))))
(@cache obj))]
(defmacro def-cached
"Just as def, however it will return an existing object if it has
already been defined with it"
[fname fbody]
(intern *ns* (symbol fname) (cache-eval fbody)))
(defmacro eval-cached
"Just as eval, however it will return an existing object if it has
already been evaluated with it"
[obj]
(cache-eval obj)))
However it'll be good if someone could share some insight why a macro
cannot call another one and what is the general solution in such a
case
Stanislav Paskalev
On Tue, May 3, 2011 at 3:50 PM, Stanislav Paskalev <[email protected]> wrote:
> Hello,
> Evaluating the form
>
> (let [cache (atom {})]
> (defmacro eval-cached
> "Just as eval, however it will return an existing object if it has
> already been evaluated with it"
> [obj]
> (when-not (contains? @cache obj)
> (reset! cache (assoc @cache obj (eval obj))))
> (@cache obj))
> (defmacro def-cached
> "Just as def, however it will return an existing object if it has
> already been defined with it"
> [fname fbody]
> (intern *ns* (symbol fname) (eval-cached fbody))))
>
> Gives me a java.lang.UnsupportedOperationException: Can't eval locals
> - for the last line of "def-cached"
>
> However, when I use eval the first defmacro by itself as a closure -
> it works perfectly. How can I make those share the cache state without
> binding it to a public symbol ?
>
> Best regards,
> Stanislav Paskalev
>
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