If you're looking for some truly unintuitive equality behavior check
this out:
user=> (def pred (Boolean. false)) ;;not a primitive but an object
#'user/pred
user=> (= pred false)
true
user=> (when pred (println "I really shouldn't print"))
I really shouldn't print
nil
Jim
On 11/12/12 13:19, Jim foo.bar wrote:
From the docs:
Equality. Returns true if x equals y, false if not. Same as
Java x.equals(y) except it also works for nil, and compares
numbers and collections in a type-independent manner. Clojure's
immutable data
structures define equals() (and thus =) as a value,*not an identity*,
comparison.
hope that helps...
Jim
On 11/12/12 13:17, Jim foo.bar wrote:
I disagree...
One of the nice things about clojrue is that, at tis hear, lies the
'equiv' operator which is basically the 'egal' fn as defined by Baker
[1993] [Equal rights for functional objects or the mroe things change
the more they stay the same]. When using '=' with data-structures you
are essentially comparing values and not types.
To come back to your example, both are sequential seqs that contain
the same values in the same order. Why shouldn't they be equal?
Clojure would not be the language we all love, if they weren't equal...
Jim
On 03/10/12 06:24, Larry Travis wrote:
What is the rationale for this?
user> (= [1 2 3 4] '(1 2 3 4))
true
I was quite surprised when this turned out to be the cause of a bug
in a function I am constructing. Vectors and lists differ so
substantially in their implementation and in their behavior that a
vector and a list should not be considered "equal" just because they
contain the same elements in the same order.
--Larry
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