equal?

        # BasicObject.equal?

(from ruby core)
---
    equal?(p1)

---

Equality --- At the Object level, #== returns `true` only if `obj` and
`other` are the same object.  Typically, this method is overridden in
descendant classes to provide class-specific meaning.

Unlike #==, the #equal? method should never be overridden by subclasses
as it is used to determine object identity (that is, `a.equal?(b)` if
and only if `a` is the same object as `b`):

    obj = "a"
    other = obj.dup

    obj == other      #=> true
    obj.equal? other  #=> false
    obj.equal? obj    #=> true

The #eql? method returns `true` if `obj` and `other` refer to the same
hash key.  This is used by Hash to test members for equality.  For any
pair of objects where #eql? returns `true`, the #hash value of both
objects must be equal. So any subclass that overrides #eql? should also
override #hash appropriately.

For objects of class Object, #eql?  is synonymous with #==.  Subclasses
normally continue this tradition by aliasing #eql? to their overridden
#== method, but there are exceptions. Numeric types, for example,
perform type conversion across #==, but not across #eql?, so:

    1 == 1.0     #=> true
    1.eql? 1.0   #=> false


(This method is an alias for BasicObject#==.)

Equality --- At the Object level, #== returns `true` only if `obj` and
`other` are the same object.  Typically, this method is overridden in
descendant classes to provide class-specific meaning.

Unlike #==, the #equal? method should never be overridden by subclasses
as it is used to determine object identity (that is, `a.equal?(b)` if
and only if `a` is the same object as `b`):

    obj = "a"
    other = obj.dup

    obj == other      #=> true
    obj.equal? other  #=> false
    obj.equal? obj    #=> true

The #eql? method returns `true` if `obj` and `other` refer to the same
hash key.  This is used by Hash to test members for equality.  For any
pair of objects where #eql? returns `true`, the #hash value of both
objects must be equal. So any subclass that overrides #eql? should also
override #hash appropriately.

For objects of class Object, #eql?  is synonymous with #==.  Subclasses
normally continue this tradition by aliasing #eql? to their overridden
#== method, but there are exceptions. Numeric types, for example,
perform type conversion across #==, but not across #eql?, so:

    1 == 1.0     #=> true
    1.eql? 1.0   #=> false