Difference between clojure.lang.Cons and clojure.lang.PersistenList

[Samuel Lê]

Hi and Happy New Year to all the Clojure mailing list,

I am am having some trouble with the two classes Cons and PersistentList:

user> (class (conj (map #(+ % 1)  '(1 2 3)) 4))
clojure.lang.Cons
user> (class '(1 2 3 4))
clojure.lang.PersistentList

My problem is that list? returns false for a Cons and true for a PersistentList.
What can I do to make my Cons a PersistentList, or is there a way to use another function instead of list? that will return true for both classes?

Many thanks,
Sam

[Cedric Greevey]

If any (...) structure will do, test with seq? instead. If you really
need a PersistentList, you'll probably have to call that class's
constructor or resort to icky hacks like

user=> (class (apply list (cons 4 '(1 2 3))))
clojure.lang.PersistentList

(though much more evil would be

user=> (class (eval `(quote ~(cons 4 '(1 2 3)))))
clojure.lang.PersistentList

instead), because for some odd reason and despite its name (list* 4
'(1 2 3)) returns a clojure.lang.Cons.

[Samuel Lê]

Yes, seq? works. Thanks for the help!

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[Cedric Greevey]

On Sun, Jan 8, 2012 at 4:11 PM, Samuel Lê <samu...@gmail.com> wrote:
> Yes, seq? works. Thanks for the help!

You're welcome.