[DRAFT] - Add copy command

Closes ruby#753

lib/irb/command/copy.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require 'mkmf'
+
+module IRB
+  module Command
+    class Copy < Base
+      category "TODO"
+      description "TODO"
+
+      help_message(<<~HELP)
+        Usage: copy (input)
+      HELP
+
+      def execute(arg)
+        output = irb_context.workspace.binding.eval(arg)
+
+        if clipboard_available?
+          copy_to_clipboard(output)
+          puts "Copied to system clipboard"
+        else
+          temp_file = write_to_tempfile(output)
+          puts "Wrote: #{temp_file}"
+        end
+      rescue StandardError => e
+        warn "Error: #{e}"
+      end
+
+      private
+
+      def copy_to_clipboard(text)
+        IO.popen(clipboard, 'w') do |io|
+          io.write(text)
+        end
+
+        raise "IOError" unless $? == 0
+      end
+
+      def write_to_tempfile(text)
+        file = Tempfile.new
+        file.write(text)
+        file.close
+        file.path
+      end
+
+      def clipboard
+        case RbConfig::CONFIG['host_os']
+        when /darwin/
+          # This is the most reliable, but we could probably also offload this
+          # to the shell to avoid MkMf logs
+          MakeMakefile.find_executable('pbopy')
+        when /linux/
+          MakeMakefile.find_executable('xclip').tap do |path|
+            path << '-selection clipboard'
+          end
+        when /mswin|mingw/
+          'clip' # => todo verify this works
+        else
+          nil
+        end
+      end
+
+      def clipboard_available?
+        !!clipboard
+      end
+    end
+  end
+end
+

lib/irb/default_commands.rb

@@ -9,6 +9,7 @@
 require_relative "command/chws"
 require_relative "command/context"
 require_relative "command/continue"
+require_relative "command/copy"
 require_relative "command/debug"
 require_relative "command/delete"
 require_relative "command/disable_irb"
@@ -200,6 +201,9 @@ def load_command(command)
     _register_with_aliases(:irb_continue, Command::Continue,
       [:continue, NO_OVERRIDE]
     )
+    _register_with_aliases(:irb_copy, Command::Copy,
+      [:copy, NO_OVERRIDE]
+    )
     _register_with_aliases(:irb_finish, Command::Finish,
       [:finish, NO_OVERRIDE]
     )