[ruby/irb] Encapsulate input details in Statement objects

(https://github.com/ruby/irb/pull/682)

* Introduce Statement class

* Split Statement class for better clarity

https://github.com/ruby/irb/commit/65e8e68690

1 files changed, 78 insertions, 0 deletions

diff --git a/lib/irb/statement.rb b/lib/irb/statement.rb
new file mode 100644
index 0000000000..9493c3ffb1
--- /dev/null
+++ b/lib/irb/statement.rb
@@ -0,0 +1,78 @@
+# 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
+
+    def evaluable_code
+      raise NotImplementedError
+    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
+
+      def evaluable_code
+        @code
+      end
+    end
+
+    class Command < Statement
+      def initialize(code, command, arg, command_class)
+        @code = code
+        @command = command
+        @arg = arg
+        @command_class = command_class
+      end
+
+      def is_assignment?
+        false
+      end
+
+      def suppresses_echo?
+        false
+      end
+
+      def should_be_handled_by_debugger?
+        IRB::ExtendCommand::DebugCommand > @command_class
+      end
+
+      def evaluable_code
+        # Hook command-specific transformation to return valid Ruby code
+        if @command_class.respond_to?(:transform_args)
+          arg = @command_class.transform_args(@arg)
+        else
+          arg = @arg
+        end
+
+        [@command, arg].compact.join(' ')
+      end
+    end
+  end
+end