1 files changed, 123 insertions, 0 deletions
diff --git a/lib/irb/command/subirb.rb b/lib/irb/command/subirb.rb
new file mode 100644
index 0000000000..85af28c1a5
--- /dev/null
+++ b/lib/irb/command/subirb.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+#
+#   multi.rb -
+#   	by Keiju ISHITSUKA(keiju@ruby-lang.org)
+#
+
+module IRB
+  # :stopdoc:
+
+  module Command
+    class MultiIRBCommand < Base
+      include RubyArgsExtractor
+
+      private
+
+      def print_deprecated_warning
+        warn <<~MSG
+          Multi-irb commands are deprecated and will be removed in IRB 2.0.0. Please use workspace commands instead.
+          If you have any use case for multi-irb, please leave a comment at https://github.com/ruby/irb/issues/653
+        MSG
+      end
+
+      def extend_irb_context
+        # this extension patches IRB context like IRB.CurrentContext
+        require_relative "../ext/multi-irb"
+      end
+
+      def print_debugger_warning
+        warn "Multi-IRB commands are not available when the debugger is enabled."
+      end
+    end
+
+    class IrbCommand < MultiIRBCommand
+      category "Multi-irb (DEPRECATED)"
+      description "Start a child IRB."
+
+      def execute(arg)
+        args, kwargs = ruby_args(arg)
+        execute_internal(*args, **kwargs)
+      end
+
+      def execute_internal(*obj)
+        print_deprecated_warning
+
+        if irb_context.with_debugger
+          print_debugger_warning
+          return
+        end
+
+        extend_irb_context
+        IRB.irb(nil, *obj)
+        puts IRB.JobManager.inspect
+      end
+    end
+
+    class Jobs < MultiIRBCommand
+      category "Multi-irb (DEPRECATED)"
+      description "List of current sessions."
+
+      def execute(_arg)
+        print_deprecated_warning
+
+        if irb_context.with_debugger
+          print_debugger_warning
+          return
+        end
+
+        extend_irb_context
+        puts IRB.JobManager.inspect
+      end
+    end
+
+    class Foreground < MultiIRBCommand
+      category "Multi-irb (DEPRECATED)"
+      description "Switches to the session of the given number."
+
+      def execute(arg)
+        args, kwargs = ruby_args(arg)
+        execute_internal(*args, **kwargs)
+      end
+
+      def execute_internal(key = nil)
+        print_deprecated_warning
+
+        if irb_context.with_debugger
+          print_debugger_warning
+          return
+        end
+
+        extend_irb_context
+
+        raise CommandArgumentError.new("Please specify the id of target IRB job (listed in the `jobs` command).") unless key
+        IRB.JobManager.switch(key)
+        puts IRB.JobManager.inspect
+      end
+    end
+
+    class Kill < MultiIRBCommand
+      category "Multi-irb (DEPRECATED)"
+      description "Kills the session with the given number."
+
+      def execute(arg)
+        args, kwargs = ruby_args(arg)
+        execute_internal(*args, **kwargs)
+      end
+
+      def execute_internal(*keys)
+        print_deprecated_warning
+
+        if irb_context.with_debugger
+          print_debugger_warning
+          return
+        end
+
+        extend_irb_context
+        IRB.JobManager.kill(*keys)
+        puts IRB.JobManager.inspect
+      end
+    end
+  end
+
+  # :startdoc:
+end