## mark a section (Learn more)

module Platform end class Platform::OS def self.calculate_current # STUB this would use real data to figure out which class to use OpenBSD end def self.resolve missing = [] klass = calculate_current() inst = klass.new klass.ancestors.each do |anc| break if anc == Platform::OS anc.verify! inst, missing end unless missing.empty? puts "Some platform functions were not found:" missing.each do |meth| puts " #{meth}" end unless ENV['PLATFORM_SOFT'] exit 1 end end end def self.attach(name, *args) @methods ||= [] @methods << name begin attach_function name, *args rescue end end def self.verify!(obj, missing) if @methods @methods.each do |meth| unless obj.respond_to?(meth) missing << meth end end end end end class POSIX < Platform::OS end class ModernUnix < POSIX attach :lchmod, [:string, :mode_t], :int attach :blah, [], :int end class BSD < ModernUnix end class OpenBSD < BSD def lchmod raise NotImplementedError, "OpenBSD does not have lchmod" end end Platform::OS.resolve

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