Add IRB::HelperMethod to support helper methods

lib/irb/command/help.rb

@@ -24,7 +24,9 @@ def execute(command_name)
 
       def help_message
         commands_info = IRB::ExtendCommandBundle.all_commands_info
+        helper_methods_info = IRB::HelperMethod.all_helper_methods_info
         commands_grouped_by_categories = commands_info.group_by { |cmd| cmd[:category] }
+        commands_grouped_by_categories["Helper methods"] = helper_methods_info
 
         user_aliases = irb_context.instance_variable_get(:@user_aliases)
 

lib/irb/default_commands.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require_relative "command"
-require_relative "command/context"
+require_relative "helper_method"
 require_relative "command/exit"
 require_relative "command/force_exit"
 require_relative "command/chws"
@@ -40,13 +40,6 @@ module ExtendCommandBundle
     # See #install_alias_method.
     OVERRIDE_ALL = 0x02
 
-    Command._register_with_aliases(:irb_context, Command::Context,
-      [
-        [:context, NO_OVERRIDE],
-        [:conf, NO_OVERRIDE],
-      ],
-    )
-
     Command._register_with_aliases(:irb_exit, Command::Exit,
       [:exit, OVERRIDE_PRIVATE_ONLY],
       [:quit, OVERRIDE_PRIVATE_ONLY],
@@ -236,6 +229,16 @@ def self.load_command(command)
       nil
     end
 
+    def self.install_helper_methods
+      HelperMethod.helper_methods.each do |name, helper_method_class|
+        define_method name do |*args, **opts, &block|
+          helper_method_class.new.execute(*args, **opts, &block)
+        end unless method_defined?(name)
+      end
+    end
+
+    install_helper_methods
+
     # Deprecated. Doesn't have any effect.
     @EXTEND_COMMANDS = []
 

lib/irb/helper_method.rb

@@ -0,0 +1,33 @@
+require_relative "helper_method/base"
+
+module IRB
+  module HelperMethod
+    @helper_methods = {}
+
+    class << self
+      attr_reader :helper_methods
+
+      def register(name, helper_class)
+        @helper_methods[name] = helper_class
+
+        if defined?(IRB::ExtendCommandBundle)
+          IRB::ExtendCommandBundle.install_helper_methods
+        end
+      end
+
+      def all_helper_methods_info
+        @helper_methods.map do |name, helper_class|
+          { display_name: name, description: helper_class.description }
+        end
+      end
+    end
+
+    # Default helper_methods
+    require_relative "helper_method/conf"
+    require_relative "helper_method/context"
+    require_relative "helper_method/irb_context"
+    register(:conf, HelperMethod::Conf)
+    register(:context, HelperMethod::Context)
+    register(:irb_context, HelperMethod::IrbContext)
+  end
+end

lib/irb/helper_method/base.rb

@@ -0,0 +1,12 @@
+module IRB
+  module HelperMethod
+    class Base
+      class << self
+        def description(description = nil)
+          @description = description if description
+          @description
+        end
+      end
+    end
+  end
+end

lib/irb/helper_method/conf.rb

@@ -0,0 +1,11 @@
+module IRB
+  module HelperMethod
+    class Conf < Base
+      description "Returns the current context."
+
+      def execute
+        IRB.CurrentContext
+      end
+    end
+  end
+end

lib/irb/helper_method/context.rb

@@ -0,0 +1,9 @@
+require_relative "conf"
+
+module IRB
+  module HelperMethod
+    class Context < Conf
+      description "Returns the current context."
+    end
+  end
+end

lib/irb/helper_method/irb_context.rb

@@ -0,0 +1,9 @@
+require_relative "conf"
+
+module IRB
+  module HelperMethod
+    class IrbContext < Conf
+      description "Returns the current context."
+    end
+  end
+end

test/irb/command/test_help.rb

@@ -62,5 +62,14 @@ def test_help_lists_user_aliases
       assert_match(/\$\s+Alias for `show_source`/, out)
       assert_match(/@\s+Alias for `whereami`/, out)
     end
+
+    def test_help_lists_helper_methods
+      out = run_ruby_file do
+        type "help"
+        type "exit"
+      end
+
+      assert_match(/Helper methods\s+conf\s+Returns the current context/, out)
+    end
   end
 end

test/irb/test_helper_method.rb

@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+require "irb"
+
+require_relative "helper"
+
+module TestIRB
+  class HelperMethodTestCase < TestCase
+    def setup
+      $VERBOSE = nil
+      @verbosity = $VERBOSE
+      save_encodings
+      IRB.instance_variable_get(:@CONF).clear
+    end
+
+    def teardown
+      $VERBOSE = @verbosity
+      restore_encodings
+    end
+
+    def execute_lines(*lines, conf: {}, main: self, irb_path: nil)
+      IRB.init_config(nil)
+      IRB.conf[:VERBOSE] = false
+      IRB.conf[:PROMPT_MODE] = :SIMPLE
+      IRB.conf.merge!(conf)
+      input = TestInputMethod.new(lines)
+      irb = IRB::Irb.new(IRB::WorkSpace.new(main), input)
+      irb.context.return_format = "=> %s\n"
+      irb.context.irb_path = irb_path if irb_path
+      IRB.conf[:MAIN_CONTEXT] = irb.context
+      IRB.conf[:USE_PAGER] = false
+      capture_output do
+        irb.eval_input
+      end
+    end
+  end
+
+  module TestHelperMethod
+    class ConfTest < HelperMethodTestCase
+      def test_conf_returns_the_context_object
+        out, err = execute_lines("conf.ap_name")
+
+        assert_empty err
+        assert_include out, "=> \"irb\""
+      end
+    end
+
+    class ContextTest < HelperMethodTestCase
+      def test_context_returns_the_context_object_and_prints_deprecation_warning
+        out, err = execute_lines("context.ap_name")
+
+        assert_empty err
+        assert_include out, "=> \"irb\""
+      end
+    end
+
+    class IrbContextTest < HelperMethodTestCase
+      def test_context_returns_the_context_object_and_prints_deprecation_warning
+        out, err = execute_lines("irb_context.ap_name")
+
+        assert_empty err
+        assert_include out, "=> \"irb\""
+      end
+    end
+  end
+
+  class HelperMethodIntegrationTest < IntegrationTestCase
+    def test_arguments_propogation
+      write_ruby <<~RUBY
+        require "irb/helper_method"
+
+        class MyHelper < IRB::HelperMethod::Base
+          description "This is a test helper"
+
+          def execute(
+            required_arg, optional_arg = nil, *splat_arg, required_keyword_arg:,
+            optional_keyword_arg: nil, **double_splat_arg, &block_arg
+          )
+            puts [required_arg, optional_arg, splat_arg, required_keyword_arg, optional_keyword_arg, double_splat_arg, block_arg.call].to_s
+          end
+        end
+
+        IRB::HelperMethod.register(:my_helper, MyHelper)
+
+        binding.irb
+      RUBY
+
+      output = run_ruby_file do
+        type <<~INPUT
+          my_helper(
+            "required", "optional", "splat", required_keyword_arg: "required",
+            optional_keyword_arg: "optional", a: 1, b: 2
+          ) { "block" }
+        INPUT
+        type "exit"
+      end
+
+      assert_include(output, '["required", "optional", ["splat"], "required", "optional", {:a=>1, :b=>2}, "block"]')
+    end
+
+    def test_helper_method_injection_can_happen_after_irb_require
+      write_ruby <<~RUBY
+        require "irb"
+
+        class MyHelper < IRB::HelperMethod::Base
+          description "This is a test helper"
+
+          def execute
+            puts "Hello from MyHelper"
+          end
+        end
+
+        IRB::HelperMethod.register(:my_helper, MyHelper)
+
+        binding.irb
+      RUBY
+
+      output = run_ruby_file do
+        type <<~INPUT
+          my_helper
+        INPUT
+        type "exit"
+      end
+
+      assert_include(output, 'Hello from MyHelper')
+    end
+  end
+end