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石橋秀仁(zerobase)書き散らす

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Smalltalk: =, ~=, ==

Equality (Same Value)

= anObject 
    "Answer whether the receiver and the argument represent the same 
    object. If = is redefined in any subclass, consider also redefining the 
    message hash."

    ^self == anObject

~= anObject 
    "Answer whether the receiver and the argument do not represent the 
    same object."

    ^self = anObject == false

If you override =, you should consider overriding hash.

Identity (Same Object)

== anObject 
    "Primitive. Answer whether the receiver and the argument are the same 
    object (have the same object pointer). Do not redefine the message == in 
    any other class! Essential. No Lookup. Do not override in any subclass. 
    See Object documentation whatIsAPrimitive."

    <primitive: 110>
    self primitiveFailed