1 files changed, 80 insertions, 0 deletions
diff --git a/lib/irb/statement.rb b/lib/irb/statement.rb
new file mode 100644
index 0000000000..a3391c12a3
--- /dev/null
+++ b/lib/irb/statement.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+module IRB
+  class Statement
+    attr_reader :code
+
+    def is_assignment?
+      raise NotImplementedError
+    end
+
+    def suppresses_echo?
+      raise NotImplementedError
+    end
+
+    def should_be_handled_by_debugger?
+      raise NotImplementedError
+    end
+
+    class EmptyInput < Statement
+      def is_assignment?
+        false
+      end
+
+      def suppresses_echo?
+        true
+      end
+
+      # Debugger takes empty input to repeat the last command
+      def should_be_handled_by_debugger?
+        true
+      end
+
+      def code
+        ""
+      end
+    end
+
+    class Expression < Statement
+      def initialize(code, is_assignment)
+        @code = code
+        @is_assignment = is_assignment
+      end
+
+      def suppresses_echo?
+        @code.match?(/;\s*\z/)
+      end
+
+      def should_be_handled_by_debugger?
+        true
+      end
+
+      def is_assignment?
+        @is_assignment
+      end
+    end
+
+    class Command < Statement
+      attr_reader :command_class, :arg
+
+      def initialize(original_code, command_class, arg)
+        @code = original_code
+        @command_class = command_class
+        @arg = arg
+      end
+
+      def is_assignment?
+        false
+      end
+
+      def suppresses_echo?
+        false
+      end
+
+      def should_be_handled_by_debugger?
+        require_relative 'command/debug'
+        IRB::Command::DebugCommand > @command_class
+      end
+    end
+  end
+end