hash - Why does Ruby hashes use eql? and not == -


i see many notions of equality in ruby. 

== eql? === equal?

and of them have different semantics. me there ought 2 of them, 1 reference equality , other value equality. don't see why ruby needed eql? , ===.

i found this question says distinction value , value , type.

specifically, don't understand why hash need check type (which test in == method itself)

hash requires keys must support eql? because needs hash code internally.

for example, 1 == 1.0 true, while 1.eql? 1.0 false. 1 , 1.0 have different hash codes, can't treated equivalent keys in hash.


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