Nested types in clojure?

Question

In clojure, how do I type type hint a type that I have created? (I want to nest the types.)

e.g. I had thought that this would work:

(deftype A 
    [#^somePrimitive  someField])

(deftype B
    [#^A Avalue])

This brings up an error message:

Unknown location:
  error: java.lang.ClassNotFoundException: A

Note: clojure types are a new feature which currently exists only in the 'new' branch of clojure.

Edit: I was confused by the different ways of type hinting in clojure for java and clojure types. java classes are hinted as

#^java.some.class

while clojure types are hinted as:

#^:some.Namespace/type

Daniel Werner · Accepted Answer · 2012-03-14 19:53:52Z

11

For each deftype, a type tag (basically a namespace-qualified keyword) is created so you don't have to AOT-compile your code before you can use the resulting class.

If type A is in the current namespace, you can write it like this:

(deftype B [^::A Avalue])

For types in other namespaces, qualify the keyword using its namespace:

(deftype B [^:user/A Avalue])

edited Mar 14, 2012 at 19:53

answered Dec 30, 2009 at 19:53

Daniel Werner

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Comments

Raoul Duke · Accepted Answer · 2009-12-30 00:12:38Z

3

(deftype B [#^:user/A Avalue]) works for me.

answered Dec 30, 2009 at 0:12

Raoul Duke

311 bronze badge

2 Comments

Rob Lachlan Over a year ago

That seems to work, but then how would I do the same thing in other files? +1, anyhow.

Rob Lachlan Over a year ago

Yup, I figured it out now. Thanks alot.

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