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Programming Ruby The Pragmatic Programmer's Guide |
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class Class
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Parent:
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Module
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Version:
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1.6
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Index:
inherited
new
new
superclass
Classes in Ruby are first-class objects---each is an instance of
class Class.
When a new class is created (typically using class Name ... end), an object of type Class is created
and assigned to a global constant (Name in this case). When Name.new is called to create a new object, the new
method in Class is run by default. This can be demonstrated by
overriding new in Class:
class Class
alias oldNew new
def new(*args)
print "Creating a new ", self.name, "\n"
oldNew(*args)
end
end
class Name
end
n = Name.new
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produces:
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class methods
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inherited
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aClass.inherited( aSubClass )
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This is a singleton method (per class) invoked by Ruby when a subclass
of aClass is created. The new subclass is passed as a
parameter.
class Top
def Top.inherited(sub)
print "New subclass: ", sub, "\n"
end
end
class Middle < Top
end
class Bottom < Middle
end
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produces:
New subclass: Middle
New subclass: Bottom
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new
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Class.new( aSuperClass=Object )
-> aClass
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Creates a new anonymous (unnamed)
class with the given superclass (or Object if no parameter is given).
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instance methods
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new
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aClass.new( [ args ]* )
-> anObject
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Creates a new object of aClass's class, then invokes that object's initialize method, passing it args.
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superclass
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aClass.superclass
-> aSuperClass or nil
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Returns the superclass of aClass, or nil.
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Class.superclass
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Module
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Object.superclass
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nil
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Extracted from the book "Programming Ruby -
The Pragmatic Programmer's Guide"
Copyright
©
2001 by Addison Wesley Longman, Inc. This material may
be distributed only subject to the terms and conditions set forth in
the Open Publication License, v1.0 or later (the latest version is
presently available at http://www.opencontent.org/openpub/)).
Distribution of substantively modified versions of this document is
prohibited without the explicit permission of the copyright holder.
Distribution of the work or derivative of the work in any standard
(paper) book form is prohibited unless prior permission is obtained
from the copyright holder.
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