In #Clojure, if you query a set for a member, and that member is present, that member is returned:
user=> (#{:a 馃槣 :c} :a)
:a
The traditional #Lisp function ASSOC has the signature
(ASSOC store key) => value
where store is assumed to be a list of (key . value) dotted pairs.
In the experimental Lisp I'm working on, I want you to be able to put maps onto assoc lists as well as (key . value) pairs, which raises the questions...
/Continued
1. What is the value of an arbitrary atom/string/keyword/number as a top level form in an assoc list; and
2. What is a set?
It occurs to me that a set could be implemented either as a hashmap where all values were their own keys, or as a hashmap there every value was T.
Which then gets us back to the assoc list.
/Continued
Suppose we have an assoc list, called 'store', with the structure:
((:one . 1) {:two 2 :three 3 :four 4} :five (:six . 6))
Then clearly,
(assoc store :1) => 1
(assoc store :three) => 3
Does it make sense to you that (assoc store :five) should return :five, which would be consistent with what #Clojure does with sets, or shout it instead return T?
I'm inclined to the latter, but I'm open to persuasion.
