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Nov
15
How can I get a list of subclasses in Ruby?
I recently came across this useful tidbit from the Ramblings blog, posted back in August…
Ruby’s ObjectSpace: Subclasses
He came up with the the following code that uses ruby’s ObjectSpace for getting a list of subclasses for a given class:
module Subclasses # return a list of the subclasses of a class def subclasses(direct = false) classes = [] if direct ObjectSpace.each_object(Class) do |c| next unless c.superclass == self classes << c end else ObjectSpace.each_object(Class) do |c| next unless c.ancestors.include?(self) and (c != self) classes << c end end classes end end Object.send(:include, Subclasses)
This allows you to do the following…
Enumerable.subclasses => [Struct::Tms, Dir, File, IO, Range, Struct, Hash, Array, String, StringIO, Socket, UNIXServer, UNIXSocket, UDPSocket, TCPServer, TCPSocket, IPSocket, BasicSocket, Struct::Group, Struct::Passwd, Zlib::GzipReader, Gem::SourceIndex]
Very cool. If you like it as much as I did… visit his blog and comment!
