should `clojure.core/=` have a zero arity?

Question

= has a single arity returning true. Should it also have a 0 arity returning true as well?

This would be in line with the results of (and), (or), (every? odd []). And would make (apply = coll) safe in all cases, even when coll was empty.

From slack:
> Agreed - I had an #(->> xs ... (apply =)) in a fdef spec and it was failing in the case when xs is empty, forcing me to write a more verbose function.

Comments

I like that! "For all a, b in c, a = b" is vacuously true for c = empty.
Also presumeably `not=` would also have a zero-arity (and return false)

Answer 1

What does it mean to compare 0 things?

Comments

How is this different from adding, and-ing or or-ing 0 things?

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Reminds me of an old Swedish joke. Roughly translates to:

- What's the difference between a fish?
- It can neither ride a bicycle!

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All elements in a empty collection is as equal all elements in a collection of one. Nothing is compared. All elements are as ordered as in a empty collections as in a collection of one. Nothing is compared. I think = < > <= >= should be true on nothing.