If I use pprint and read-string to serialize and deserialize data
w/o function references it works o.k. This is clojure 1.3.
e.g. save something to disk, restart the vm, read it in ok.
user=> (def foo {:a 1 :b 2 :c ["more" "stuff"]})
user=> (def output (java.io.FileWriter. "foo.clj"))
user=> (clojure.pprint/pprint foo output)
user=> (.close output)
$ cat foo.clj
{:a 1, :b 2, :c ["more" "stuff"]}
user=> (def foo (read-string (slurp "foo.clj"))) ;;; all good
However, if there's a function in that data structure, I cannot
read the forms back in.
user=> (def foo (assoc foo :d clojure.core/+))
user=> foo
{:d #<core$_PLUS_ clojure.core$_PLUS_@1ce00b4>, :a 1, :b 2, :c
["more" "stuff"]}
user=> ;; save to file as above...
$ cat foo.clj
{:d #<core$_PLUS_ clojure.core$_PLUS_@1ce00b4>,
:a 1,
:b 2,
:c ["more" "stuff"]}
user=> (def foo (read-string (slurp "foo.clj")))
java.lang.RuntimeException: java.lang.Exception: Unreadable form
(NO_SOURCE_FILE:1)
As an experiment, I edited the file and changed the object
reference to the fully qualified name of the function, I could
read the structure in, and it appears to be a function (according
to clojure test), but it prints differently, and it does not
behave like + anymore, instead I simply get the last argument
back.
$ cat foo.clj
{:d clojure.core/+
:a 1,
:b 2,
:c ["more" "stuff"]}
user=> (def foo (read-string (slurp "foo.clj")))
#'user/foo
user=> (require 'clojure.test)
nil
user=> (clojure.test/function? (foo :d))
true
user=> +
#<core$_PLUS_ clojure.core$_PLUS_@1a19458>
user=> (foo :d) ;;; notice that it prints differently
clojure.core/+
user=> ((foo :d) 4 5) ;;; what don't I understand about this?
5
user=> (def fun (foo :d))
#'user/fun
user=> (fun 4 5) ;;; didn't expect different...
5
user=> (+ 4 5)
9
I'm not sure what I don't undertand about what I had going on in
the last example, but that isn't my primary question.
My primary question is, how do I serialize and deserialize data with
function references in it?
Thanks
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