diff --git a/lib/irb.rb b/lib/irb.rb
index daa0d64f2..2c1331177 100644
--- a/lib/irb.rb
+++ b/lib/irb.rb
@@ -915,7 +915,7 @@ class Irb
     # Creates a new irb session
     def initialize(workspace = nil, input_method = nil)
       @context = Context.new(self, workspace, input_method)
-      @context.workspace.load_commands_to_main
+      @context.workspace.load_helper_methods_to_main
       @signal_status = :IN_IRB
       @scanner = RubyLex.new
       @line_no = 1
@@ -935,7 +935,7 @@ def debug_break
     def debug_readline(binding)
       workspace = IRB::WorkSpace.new(binding)
       context.workspace = workspace
-      context.workspace.load_commands_to_main
+      context.workspace.load_helper_methods_to_main
       @line_no += 1
 
       # When users run:
@@ -1002,7 +1002,7 @@ def eval_input
               return statement.code
             end
 
-            @context.evaluate(statement.evaluable_code, line_no)
+            statement.execute(@context, line_no)
 
             if @context.echo? && !statement.suppresses_echo?
               if statement.is_assignment?
@@ -1058,9 +1058,7 @@ def readmultiline
         end
 
         code << line
-
-        # Accept any single-line input for symbol aliases or commands that transform args
-        return code if single_line_command?(code)
+        return code if command?(code)
 
         tokens, opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
         return code if terminated
@@ -1086,23 +1084,40 @@ def each_top_level_statement
 
     def build_statement(code)
       code.force_encoding(@context.io.encoding)
-      command_or_alias, arg = code.split(/\s/, 2)
-      # Transform a non-identifier alias (@, $) or keywords (next, break)
-      command_name = @context.command_aliases[command_or_alias.to_sym]
-      command = command_name || command_or_alias
-      command_class = ExtendCommandBundle.load_command(command)
-
-      if command_class
-        Statement::Command.new(code, command, arg, command_class)
+      if (command_class, arg = parse_command(code))
+        Statement::Command.new(code, command_class, arg)
       else
         is_assignment_expression = @scanner.assignment_expression?(code, local_variables: @context.local_variables)
         Statement::Expression.new(code, is_assignment_expression)
       end
     end
 
-    def single_line_command?(code)
-      command = code.split(/\s/, 2).first
-      @context.symbol_alias?(command) || @context.transform_args?(command)
+    ASSIGN_OPERATORS = %w[= += -= *= /= %= **= &= |= &&= ||= ^= <<= >>=]
+    COMMAND_LIKE_ASSIGN_REGEXP = /\A[a-z_]\w* #{Regexp.union(ASSIGN_OPERATORS)}( |$)/
+
+    def parse_command(code)
+      command_or_alias, arg = code.strip.split(/\s/, 2)
+      return unless code.lines.size == 1 && command_or_alias
+      return if COMMAND_LIKE_ASSIGN_REGEXP.match?(code)
+
+      # Check visibility
+      local_variable = @context.local_variables.include?(command_or_alias.to_sym)
+      public_method = !!@context.main.public_method(command_or_alias) rescue false
+      private_method = !public_method && !!@context.main.method(command_or_alias) rescue false
+      return unless ExtendCommandBundle.execute_as_command?(
+        command_or_alias,
+        public_method: public_method,
+        private_method: private_method,
+        local_variable: local_variable
+      )
+
+      command_name = @context.command_aliases[command_or_alias.to_sym] || command_or_alias
+      command_class = ExtendCommandBundle.load_command(command_name)
+      [command_class, arg] if command_class
+    end
+
+    def command?(code)
+      !!parse_command(code)
     end
 
     def configure_io
@@ -1120,8 +1135,7 @@ def configure_io
               false
             end
           else
-            # Accept any single-line input for symbol aliases or commands that transform args
-            next true if single_line_command?(code)
+            next true if command?(code)
 
             _tokens, _opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
             terminated
diff --git a/lib/irb/cmd/backtrace.rb b/lib/irb/cmd/backtrace.rb
index f63289461..7bd4a403b 100644
--- a/lib/irb/cmd/backtrace.rb
+++ b/lib/irb/cmd/backtrace.rb
@@ -7,12 +7,8 @@ module IRB
 
   module ExtendCommand
     class Backtrace < DebugCommand
-      def self.transform_args(args)
-        args&.dump
-      end
-
-      def execute(*args)
-        super(pre_cmds: ["backtrace", *args].join(" "))
+      def execute(arg)
+        execute_debug_command(pre_cmds: "backtrace #{arg}")
       end
     end
   end
diff --git a/lib/irb/cmd/break.rb b/lib/irb/cmd/break.rb
index df259a90c..766626c86 100644
--- a/lib/irb/cmd/break.rb
+++ b/lib/irb/cmd/break.rb
@@ -7,12 +7,8 @@ module IRB
 
   module ExtendCommand
     class Break < DebugCommand
-      def self.transform_args(args)
-        args&.dump
-      end
-
-      def execute(args = nil)
-        super(pre_cmds: "break #{args}")
+      def execute(arg)
+        execute_debug_command(pre_cmds: "break #{arg}")
       end
     end
   end
diff --git a/lib/irb/cmd/catch.rb b/lib/irb/cmd/catch.rb
index 40b62c753..6cae61270 100644
--- a/lib/irb/cmd/catch.rb
+++ b/lib/irb/cmd/catch.rb
@@ -7,12 +7,8 @@ module IRB
 
   module ExtendCommand
     class Catch < DebugCommand
-      def self.transform_args(args)
-        args&.dump
-      end
-
-      def execute(*args)
-        super(pre_cmds: ["catch", *args].join(" "))
+      def execute(arg)
+        execute_debug_command(pre_cmds: "catch #{arg}")
       end
     end
   end
diff --git a/lib/irb/cmd/chws.rb b/lib/irb/cmd/chws.rb
index 31045f9bb..e91673033 100644
--- a/lib/irb/cmd/chws.rb
+++ b/lib/irb/cmd/chws.rb
@@ -16,7 +16,7 @@ class CurrentWorkingWorkspace < Nop
       category "Workspace"
       description "Show the current workspace."
 
-      def execute(*obj)
+      def execute_as_ruby(*obj)
         irb_context.main
       end
     end
@@ -25,7 +25,7 @@ class ChangeWorkspace < Nop
       category "Workspace"
       description "Change the current workspace to an object."
 
-      def execute(*obj)
+      def execute_as_ruby(*obj)
         irb_context.change_workspace(*obj)
         irb_context.main
       end
diff --git a/lib/irb/cmd/context.rb b/lib/irb/cmd/context.rb
new file mode 100644
index 000000000..706517974
--- /dev/null
+++ b/lib/irb/cmd/context.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require_relative "nop"
+
+module IRB
+  module ExtendCommand
+    class Context < Nop
+      category "IRB"
+      description "Displays current configuration."
+
+      def execute(arg)
+        # This command just displays the configuration.
+        # Modifying the configuration is achieved by sending a message to IRB.conf.
+        Pager.page_content(IRB.CurrentContext.inspect)
+      end
+    end
+  end
+end
diff --git a/lib/irb/cmd/continue.rb b/lib/irb/cmd/continue.rb
index 9136177ee..b5d15adb6 100644
--- a/lib/irb/cmd/continue.rb
+++ b/lib/irb/cmd/continue.rb
@@ -7,8 +7,8 @@ module IRB
 
   module ExtendCommand
     class Continue < DebugCommand
-      def execute(*args)
-        super(do_cmds: ["continue", *args].join(" "))
+      def execute_as_ruby(*args)
+        execute_debug_command(do_cmds: ["continue", *args].join(" "))
       end
     end
   end
diff --git a/lib/irb/cmd/debug.rb b/lib/irb/cmd/debug.rb
index e236084ca..fc99f2b90 100644
--- a/lib/irb/cmd/debug.rb
+++ b/lib/irb/cmd/debug.rb
@@ -14,7 +14,11 @@ class Debug < Nop
         binding.method(:irb).source_location.first,
       ].map { |file| /\A#{Regexp.escape(file)}:\d+:in `irb'\z/ }
 
-      def execute(pre_cmds: nil, do_cmds: nil)
+      def execute(_arg)
+        execute_debug_command
+      end
+
+      def execute_debug_command(pre_cmds: nil, do_cmds: nil)
         if irb_context.with_debugger
           # If IRB is already running with a debug session, throw the command and IRB.debug_readline will pass it to the debugger.
           if cmd = pre_cmds || do_cmds
diff --git a/lib/irb/cmd/delete.rb b/lib/irb/cmd/delete.rb
index aeb26d257..23e5facb6 100644
--- a/lib/irb/cmd/delete.rb
+++ b/lib/irb/cmd/delete.rb
@@ -7,8 +7,8 @@ module IRB
 
   module ExtendCommand
     class Delete < DebugCommand
-      def execute(*args)
-        super(pre_cmds: ["delete", *args].join(" "))
+      def execute_as_ruby(*arg)
+        execute_debug_command(pre_cmds: ["delete", *args].join(" "))
       end
     end
   end
diff --git a/lib/irb/cmd/edit.rb b/lib/irb/cmd/edit.rb
index 69606beea..30dcdc7a6 100644
--- a/lib/irb/cmd/edit.rb
+++ b/lib/irb/cmd/edit.rb
@@ -10,19 +10,8 @@ class Edit < Nop
       category "Misc"
       description 'Open a file with the editor command defined with `ENV["VISUAL"]` or `ENV["EDITOR"]`.'
 
-      class << self
-        def transform_args(args)
-          # Return a string literal as is for backward compatibility
-          if args.nil? || args.empty? || string_literal?(args)
-            args
-          else # Otherwise, consider the input as a String for convenience
-            args.strip.dump
-          end
-        end
-      end
-
-      def execute(*args)
-        path = args.first
+      def execute(arg)
+        path = unwrap_string_literal(arg)
 
         if path.nil? && (irb_path = @irb_context.irb_path)
           path = irb_path
diff --git a/lib/irb/cmd/exit.rb b/lib/irb/cmd/exit.rb
new file mode 100644
index 000000000..d02b99322
--- /dev/null
+++ b/lib/irb/cmd/exit.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require_relative "nop"
+
+module IRB
+  module ExtendCommand
+    class Exit < Nop
+      category "IRB"
+      description "Quits the current irb context."
+
+      def execute(arg)
+        IRB.CurrentContext.exit(arg.to_i)
+      end
+    end
+  end
+end
diff --git a/lib/irb/cmd/finish.rb b/lib/irb/cmd/finish.rb
index 29f100feb..83a8aa93a 100644
--- a/lib/irb/cmd/finish.rb
+++ b/lib/irb/cmd/finish.rb
@@ -7,8 +7,8 @@ module IRB
 
   module ExtendCommand
     class Finish < DebugCommand
-      def execute(*args)
-        super(do_cmds: ["finish", *args].join(" "))
+      def execute_as_ruby(*args)
+        execute_debug_command(do_cmds: ["finish", *args].join(" "))
       end
     end
   end
diff --git a/lib/irb/cmd/help.rb b/lib/irb/cmd/help.rb
index 64b885c38..3fa65998a 100644
--- a/lib/irb/cmd/help.rb
+++ b/lib/irb/cmd/help.rb
@@ -14,7 +14,7 @@ class Help < ShowDoc
         For command help, please use `show_cmds` for now.
       MSG
 
-      def execute(*names)
+      def execute(arg)
         warn DEPRECATION_MESSAGE
         super
       end
diff --git a/lib/irb/cmd/history.rb b/lib/irb/cmd/history.rb
index 5b712fa44..61cd6fb46 100644
--- a/lib/irb/cmd/history.rb
+++ b/lib/irb/cmd/history.rb
@@ -12,14 +12,12 @@ class History < Nop
       category "IRB"
       description "Shows the input history. `-g [query]` or `-G [query]` allows you to filter the output."
 
-      def self.transform_args(args)
-        match = args&.match(/(-g|-G)\s+(?<grep>.+)\s*\n\z/)
-        return unless match
+      def execute(arg)
 
-        "grep: #{Regexp.new(match[:grep]).inspect}"
-      end
+        if (match = arg&.match(/(-g|-G)\s+(?<grep>.+)\s*\n\z/))
+          grep = Regexp.new(match[:grep])
+        end
 
-      def execute(grep: nil)
         formatted_inputs = irb_context.io.class::HISTORY.each_with_index.reverse_each.filter_map do |input, index|
           next if grep && !input.match?(grep)
 
diff --git a/lib/irb/cmd/info.rb b/lib/irb/cmd/info.rb
index 2c0a32b34..48b3c887e 100644
--- a/lib/irb/cmd/info.rb
+++ b/lib/irb/cmd/info.rb
@@ -7,12 +7,8 @@ module IRB
 
   module ExtendCommand
     class Info < DebugCommand
-      def self.transform_args(args)
-        args&.dump
-      end
-
-      def execute(*args)
-        super(pre_cmds: ["info", *args].join(" "))
+      def execute(arg)
+        execute_debug_command(pre_cmds: "info #{arg}")
       end
     end
   end
diff --git a/lib/irb/cmd/irb_info.rb b/lib/irb/cmd/irb_info.rb
index 5b905a09b..f4a7fe9ac 100644
--- a/lib/irb/cmd/irb_info.rb
+++ b/lib/irb/cmd/irb_info.rb
@@ -10,7 +10,7 @@ class IrbInfo < Nop
       category "IRB"
       description "Show information about IRB."
 
-      def execute
+      def execute(_arg)
         str  = "Ruby version: #{RUBY_VERSION}\n"
         str += "IRB version: #{IRB.version}\n"
         str += "InputMethod: #{IRB.CurrentContext.io.inspect}\n"
diff --git a/lib/irb/cmd/load.rb b/lib/irb/cmd/load.rb
index a3e797a7e..8499a2faa 100644
--- a/lib/irb/cmd/load.rb
+++ b/lib/irb/cmd/load.rb
@@ -23,7 +23,7 @@ class Load < LoaderCommand
       category "IRB"
       description "Load a Ruby file."
 
-      def execute(file_name = nil, priv = nil)
+      def execute_as_ruby(file_name = nil, priv = nil)
         raise_cmd_argument_error unless file_name
         irb_load(file_name, priv)
       end
@@ -32,7 +32,7 @@ def execute(file_name = nil, priv = nil)
     class Require < LoaderCommand
       category "IRB"
       description "Require a Ruby file."
-      def execute(file_name = nil)
+      def execute_as_ruby(file_name = nil)
         raise_cmd_argument_error unless file_name
 
         rex = Regexp.new("#{Regexp.quote(file_name)}(\.o|\.rb)?")
@@ -65,7 +65,7 @@ class Source < LoaderCommand
       category "IRB"
       description "Loads a given file in the current session."
 
-      def execute(file_name = nil)
+      def execute_as_ruby(file_name = nil)
         raise_cmd_argument_error unless file_name
 
         source_file(file_name)
diff --git a/lib/irb/cmd/ls.rb b/lib/irb/cmd/ls.rb
index 791b1c1b2..d6d214530 100644
--- a/lib/irb/cmd/ls.rb
+++ b/lib/irb/cmd/ls.rb
@@ -14,20 +14,20 @@ class Ls < Nop
       category "Context"
       description "Show methods, constants, and variables. `-g [query]` or `-G [query]` allows you to filter out the output."
 
-      def self.transform_args(args)
-        if match = args&.match(/\A(?<args>.+\s|)(-g|-G)\s+(?<grep>[^\s]+)\s*\n\z/)
-          args = match[:args]
-          "#{args}#{',' unless args.chomp.empty?} grep: /#{match[:grep]}/"
+      def execute(arg)
+        if match = arg&.match(/\A(?<args>.+\s|)(-g|-G)\s+(?<grep>.+)$/)
+          arg = @irb_context.workspace.binding.eval(match[:args])
+          grep = Regexp.new(match[:grep])
+          (arg,), _kwargs = ruby_args(arg)
         else
-          args
+          (arg,), kwargs = ruby_args(arg)
+          grep = kwargs[:grep]
         end
-      end
 
-      def execute(*arg, grep: nil)
         o = Output.new(grep: grep)
 
-        obj    = arg.empty? ? irb_context.workspace.main : arg.first
-        locals = arg.empty? ? irb_context.workspace.binding.local_variables : []
+        obj    = arg.nil? ? irb_context.workspace.main : arg
+        locals = arg.nil? ? irb_context.workspace.binding.local_variables : []
         klass  = (obj.class == Class || obj.class == Module ? obj : obj.class)
 
         o.dump("constants", obj.constants) if obj.respond_to?(:constants)
diff --git a/lib/irb/cmd/measure.rb b/lib/irb/cmd/measure.rb
index 4e1125a0a..ff404e4ad 100644
--- a/lib/irb/cmd/measure.rb
+++ b/lib/irb/cmd/measure.rb
@@ -12,15 +12,19 @@ def initialize(*args)
         super(*args)
       end
 
-      def execute(type = nil, arg = nil)
-        # Please check IRB.init_config in lib/irb/init.rb that sets
-        # IRB.conf[:MEASURE_PROC] to register default "measure" methods,
-        # "measure :time" (abbreviated as "measure") and "measure :stackprof".
-
-        if block_given?
+      def execute(arg)
+        if arg&.match?(/^do| do|\{/)
           warn 'Configure IRB.conf[:MEASURE_PROC] to add custom measure methods.'
           return
         end
+        args, kwargs = ruby_args(arg)
+        execute_internal(*args, **kwargs)
+      end
+
+      def execute_internal(type = nil, arg = nil)
+        # Please check IRB.init_config in lib/irb/init.rb that sets
+        # IRB.conf[:MEASURE_PROC] to register default "measure" methods,
+        # "measure :time" (abbreviated as "measure") and "measure :stackprof".
 
         case type
         when :off
diff --git a/lib/irb/cmd/next.rb b/lib/irb/cmd/next.rb
index d29c82e7f..03fd4ecc8 100644
--- a/lib/irb/cmd/next.rb
+++ b/lib/irb/cmd/next.rb
@@ -7,8 +7,8 @@ module IRB
 
   module ExtendCommand
     class Next < DebugCommand
-      def execute(*args)
-        super(do_cmds: ["next", *args].join(" "))
+      def execute_as_ruby(*args)
+        execute_debug_command(do_cmds: ["next", *args].join(" "))
       end
     end
   end
diff --git a/lib/irb/cmd/nop.rb b/lib/irb/cmd/nop.rb
index 7fb197c51..a71bb4f78 100644
--- a/lib/irb/cmd/nop.rb
+++ b/lib/irb/cmd/nop.rb
@@ -10,6 +10,10 @@ module IRB
   module ExtendCommand
     class CommandArgumentError < StandardError; end
 
+    def self.extract_ruby_args(*args, **kwargs)
+      throw :EXTRACT_RUBY_ARGS, [args, kwargs]
+    end
+
     class Nop
       class << self
         def category(category = nil)
@@ -21,18 +25,16 @@ def description(description = nil)
           @description = description if description
           @description
         end
-
-        private
-
-        def string_literal?(args)
-          sexp = Ripper.sexp(args)
-          sexp && sexp.size == 2 && sexp.last&.first&.first == :string_literal
-        end
       end
 
-      def self.execute(irb_context, *opts, **kwargs, &block)
+      def self.execute(irb_context, arg)
         command = new(irb_context)
-        command.execute(*opts, **kwargs, &block)
+        if command.respond_to?(:execute_as_ruby)
+          args, kwargs = command.ruby_args(arg)
+          command.execute_as_ruby(*args, **kwargs)
+        else
+          command.execute(arg)
+        end
       rescue CommandArgumentError => e
         puts e.message
       end
@@ -43,7 +45,26 @@ def initialize(irb_context)
 
       attr_reader :irb_context
 
-      def execute(*opts)
+      def unwrap_string_literal(str)
+        return unless str
+
+        sexp = Ripper.sexp(str)
+        if sexp && sexp.size == 2 && sexp.last&.first&.first == :string_literal
+          @irb_context.workspace.binding.eval(str).to_s
+        else
+          str
+        end
+      end
+
+      def ruby_args(arg)
+        # When arg includes `;` for example: "1, kw: (2; 3); 4",
+        # `IRB::ExtendCommand.extract_ruby_args 1, kw: (2; 3); 4` will return 4, but we want `[[1], { kw: 3 }]`.
+        catch(:EXTRACT_RUBY_ARGS) do
+          @irb_context.workspace.binding.eval "IRB::ExtendCommand.extract_ruby_args #{arg}"
+        end || [[], {}]
+      end
+
+      def execute(arg)
         #nop
       end
     end
diff --git a/lib/irb/cmd/pushws.rb b/lib/irb/cmd/pushws.rb
index 59996ceb0..9902acd0b 100644
--- a/lib/irb/cmd/pushws.rb
+++ b/lib/irb/cmd/pushws.rb
@@ -15,7 +15,7 @@ class Workspaces < Nop
       category "Workspace"
       description "Show workspaces."
 
-      def execute(*obj)
+      def execute(_arg)
         irb_context.workspaces.collect{|ws| ws.main}
       end
     end
@@ -24,9 +24,9 @@ class PushWorkspace < Workspaces
       category "Workspace"
       description "Push an object to the workspace stack."
 
-      def execute(*obj)
+      def execute_as_ruby(*obj)
         irb_context.push_workspace(*obj)
-        super
+        execute(nil)
       end
     end
 
@@ -34,9 +34,9 @@ class PopWorkspace < Workspaces
       category "Workspace"
       description "Pop a workspace from the workspace stack."
 
-      def execute(*obj)
+      def execute_as_ruby(*obj)
         irb_context.pop_workspace(*obj)
-        super
+        execute(nil)
       end
     end
   end
diff --git a/lib/irb/cmd/show_cmds.rb b/lib/irb/cmd/show_cmds.rb
index a8d899e4a..770a39095 100644
--- a/lib/irb/cmd/show_cmds.rb
+++ b/lib/irb/cmd/show_cmds.rb
@@ -12,7 +12,7 @@ class ShowCmds < Nop
       category "IRB"
       description "List all available commands and their description."
 
-      def execute(*args)
+      def execute(_arg)
         commands_info = IRB::ExtendCommandBundle.all_commands_info
         commands_grouped_by_categories = commands_info.group_by { |cmd| cmd[:category] }
 
diff --git a/lib/irb/cmd/show_doc.rb b/lib/irb/cmd/show_doc.rb
index 99dd9ab95..f45ad26a5 100644
--- a/lib/irb/cmd/show_doc.rb
+++ b/lib/irb/cmd/show_doc.rb
@@ -5,21 +5,11 @@
 module IRB
   module ExtendCommand
     class ShowDoc < Nop
-      class << self
-        def transform_args(args)
-          # Return a string literal as is for backward compatibility
-          if args.empty? || string_literal?(args)
-            args
-          else # Otherwise, consider the input as a String for convenience
-            args.strip.dump
-          end
-        end
-      end
-
       category "Context"
       description "Enter the mode to look up RI documents."
 
-      def execute(*names)
+      def execute(arg)
+        name = unwrap_string_literal(arg)
         require 'rdoc/ri/driver'
 
         unless ShowDoc.const_defined?(:Ri)
@@ -27,15 +17,13 @@ def execute(*names)
           ShowDoc.const_set(:Ri, RDoc::RI::Driver.new(opts))
         end
 
-        if names.empty?
+        if name.nil?
           Ri.interactive
         else
-          names.each do |name|
-            begin
-              Ri.display_name(name.to_s)
-            rescue RDoc::RI::Error
-              puts $!.message
-            end
+          begin
+            Ri.display_name(name)
+          rescue RDoc::RI::Error
+            puts $!.message
           end
         end
 
diff --git a/lib/irb/cmd/show_source.rb b/lib/irb/cmd/show_source.rb
index 826cb11ed..9562104e1 100644
--- a/lib/irb/cmd/show_source.rb
+++ b/lib/irb/cmd/show_source.rb
@@ -11,18 +11,8 @@ class ShowSource < Nop
       category "Context"
       description "Show the source code of a given method or constant."
 
-      class << self
-        def transform_args(args)
-          # Return a string literal as is for backward compatibility
-          if args.empty? || string_literal?(args)
-            args
-          else # Otherwise, consider the input as a String for convenience
-            args.strip.dump
-          end
-        end
-      end
-
-      def execute(str = nil)
+      def execute(arg)
+        str = unwrap_string_literal(arg)
         unless str.is_a?(String)
           puts "Error: Expected a string but got #{str.inspect}"
           return
diff --git a/lib/irb/cmd/step.rb b/lib/irb/cmd/step.rb
index 2bc74a9d7..53162e2ed 100644
--- a/lib/irb/cmd/step.rb
+++ b/lib/irb/cmd/step.rb
@@ -7,8 +7,8 @@ module IRB
 
   module ExtendCommand
     class Step < DebugCommand
-      def execute(*args)
-        super(do_cmds: ["step", *args].join(" "))
+      def execute_as_ruby(*args)
+        execute_debug_command(do_cmds: ["step", *args].join(" "))
       end
     end
   end
diff --git a/lib/irb/cmd/subirb.rb b/lib/irb/cmd/subirb.rb
index 5ffd64641..96e87acc8 100644
--- a/lib/irb/cmd/subirb.rb
+++ b/lib/irb/cmd/subirb.rb
@@ -11,10 +11,6 @@ module IRB
 
   module ExtendCommand
     class MultiIRBCommand < Nop
-      def execute(*args)
-        extend_irb_context
-      end
-
       private
 
       def print_deprecated_warning
@@ -38,7 +34,7 @@ class IrbCommand < MultiIRBCommand
       category "Multi-irb (DEPRECATED)"
       description "Start a child IRB."
 
-      def execute(*obj)
+      def execute_as_ruby(*obj)
         print_deprecated_warning
 
         if irb_context.with_debugger
@@ -46,7 +42,7 @@ def execute(*obj)
           return
         end
 
-        super
+        extend_irb_context
         IRB.irb(nil, *obj)
       end
     end
@@ -55,7 +51,7 @@ class Jobs < MultiIRBCommand
       category "Multi-irb (DEPRECATED)"
       description "List of current sessions."
 
-      def execute
+      def execute(_arg)
         print_deprecated_warning
 
         if irb_context.with_debugger
@@ -63,7 +59,7 @@ def execute
           return
         end
 
-        super
+        extend_irb_context
         IRB.JobManager
       end
     end
@@ -72,7 +68,7 @@ class Foreground < MultiIRBCommand
       category "Multi-irb (DEPRECATED)"
       description "Switches to the session of the given number."
 
-      def execute(key = nil)
+      def execute_as_ruby(key = nil)
         print_deprecated_warning
 
         if irb_context.with_debugger
@@ -80,7 +76,7 @@ def execute(key = nil)
           return
         end
 
-        super
+        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)
@@ -91,7 +87,7 @@ class Kill < MultiIRBCommand
       category "Multi-irb (DEPRECATED)"
       description "Kills the session with the given number."
 
-      def execute(*keys)
+      def execute_as_ruby(*keys)
         print_deprecated_warning
 
         if irb_context.with_debugger
@@ -99,7 +95,7 @@ def execute(*keys)
           return
         end
 
-        super
+        extend_irb_context
         IRB.JobManager.kill(*keys)
       end
     end
diff --git a/lib/irb/cmd/whereami.rb b/lib/irb/cmd/whereami.rb
index 8f56ba073..9f63bb900 100644
--- a/lib/irb/cmd/whereami.rb
+++ b/lib/irb/cmd/whereami.rb
@@ -10,7 +10,7 @@ class Whereami < Nop
       category "Context"
       description "Show the source code around binding.irb again."
 
-      def execute(*)
+      def execute(_arg)
         code = irb_context.workspace.code_around_binding
         if code
           puts code
diff --git a/lib/irb/context.rb b/lib/irb/context.rb
index c3690fcac..ebe593d71 100644
--- a/lib/irb/context.rb
+++ b/lib/irb/context.rb
@@ -611,17 +611,5 @@ def inspect # :nodoc:
     def local_variables # :nodoc:
       workspace.binding.local_variables
     end
-
-    # Return true if it's aliased from the argument and it's not an identifier.
-    def symbol_alias?(command)
-      return nil if command.match?(/\A\w+\z/)
-      command_aliases.key?(command.to_sym)
-    end
-
-    # Return true if the command supports transforming args
-    def transform_args?(command)
-      command = command_aliases.fetch(command.to_sym, command)
-      ExtendCommandBundle.load_command(command)&.respond_to?(:transform_args)
-    end
   end
 end
diff --git a/lib/irb/extend-command.rb b/lib/irb/extend-command.rb
index 072069d4c..160bddc6a 100644
--- a/lib/irb/extend-command.rb
+++ b/lib/irb/extend-command.rb
@@ -7,41 +7,23 @@
 module IRB # :nodoc:
   # Installs the default irb extensions command bundle.
   module ExtendCommandBundle
-    EXCB = ExtendCommandBundle # :nodoc:
-
-    # See #install_alias_method.
+    # See ExtendCommandBundle.execute_as_command?.
     NO_OVERRIDE = 0
-    # See #install_alias_method.
     OVERRIDE_PRIVATE_ONLY = 0x01
-    # See #install_alias_method.
     OVERRIDE_ALL = 0x02
 
-    # Quits the current irb context
-    #
-    # +ret+ is the optional signal or message to send to Context#exit
-    #
-    # Same as <code>IRB.CurrentContext.exit</code>.
-    def irb_exit(ret = 0)
-      irb_context.exit(ret)
-    end
-
-    # Displays current configuration.
-    #
-    # Modifying the configuration is achieved by sending a message to IRB.conf.
-    def irb_context
-      IRB.CurrentContext
-    end
-
-    @ALIASES = [
-      [:context, :irb_context, NO_OVERRIDE],
-      [:conf, :irb_context, NO_OVERRIDE],
-      [:irb_quit, :irb_exit, OVERRIDE_PRIVATE_ONLY],
-      [:exit, :irb_exit, OVERRIDE_PRIVATE_ONLY],
-      [:quit, :irb_exit, OVERRIDE_PRIVATE_ONLY],
-    ]
-
-
     @EXTEND_COMMANDS = [
+      [
+        :irb_context, :Context, "cmd/context",
+        [:context, NO_OVERRIDE],
+        [:conf, NO_OVERRIDE],
+      ],
+      [
+        :irb_exit, :Exit, "cmd/exit",
+        [:exit, OVERRIDE_PRIVATE_ONLY],
+        [:quit, OVERRIDE_PRIVATE_ONLY],
+        [:irb_quit, OVERRIDE_PRIVATE_ONLY],
+      ],
       [
         :irb_current_working_workspace, :CurrentWorkingWorkspace, "cmd/chws",
         [:cwws, NO_OVERRIDE],
@@ -200,6 +182,30 @@ def irb_context
       ]
     ]
 
+    def self.command_override_policies
+      @@command_override_policies ||= @EXTEND_COMMANDS.flat_map do |cmd_name, cmd_class, load_file, *aliases|
+        [[cmd_name, OVERRIDE_ALL]] + aliases
+      end.to_h
+    end
+
+    def self.execute_as_command?(name, public_method:, private_method:, local_variable:)
+      case command_override_policies[name.to_sym]
+      when OVERRIDE_ALL, nil
+        true
+      when OVERRIDE_PRIVATE_ONLY
+        !public_method && !local_variable
+      when NO_OVERRIDE
+        !public_method && !private_method && !local_variable
+      end
+    end
+
+    def self.has_helper_method?
+      IRB::ExtendCommandBundle.instance_methods.any?
+    end
+
+    def self.command_names
+      @@command_names ||= command_override_policies.keys.map(&:to_s)
+    end
 
     @@commands = []
 
@@ -242,79 +248,6 @@ def self.load_command(command)
       end
       nil
     end
-
-    # Installs the default irb commands.
-    def self.install_extend_commands
-      for args in @EXTEND_COMMANDS
-        def_extend_command(*args)
-      end
-    end
-
-    # Evaluate the given +cmd_name+ on the given +cmd_class+ Class.
-    #
-    # Will also define any given +aliases+ for the method.
-    #
-    # The optional +load_file+ parameter will be required within the method
-    # definition.
-    def self.def_extend_command(cmd_name, cmd_class, load_file, *aliases)
-      case cmd_class
-      when Symbol
-        cmd_class = cmd_class.id2name
-      when String
-      when Class
-        cmd_class = cmd_class.name
-      end
-
-      line = __LINE__; eval %[
-        def #{cmd_name}(*opts, **kwargs, &b)
-          Kernel.require_relative "#{load_file}"
-          ::IRB::ExtendCommand::#{cmd_class}.execute(irb_context, *opts, **kwargs, &b)
-        end
-      ], nil, __FILE__, line
-
-      for ali, flag in aliases
-        @ALIASES.push [ali, cmd_name, flag]
-      end
-    end
-
-    # Installs alias methods for the default irb commands, see
-    # ::install_extend_commands.
-    def install_alias_method(to, from, override = NO_OVERRIDE)
-      to = to.id2name unless to.kind_of?(String)
-      from = from.id2name unless from.kind_of?(String)
-
-      if override == OVERRIDE_ALL or
-          (override == OVERRIDE_PRIVATE_ONLY) && !respond_to?(to) or
-          (override == NO_OVERRIDE) &&  !respond_to?(to, true)
-        target = self
-        (class << self; self; end).instance_eval{
-          if target.respond_to?(to, true) &&
-            !target.respond_to?(EXCB.irb_original_method_name(to), true)
-            alias_method(EXCB.irb_original_method_name(to), to)
-          end
-          alias_method to, from
-        }
-      else
-        Kernel.warn "irb: warn: can't alias #{to} from #{from}.\n"
-      end
-    end
-
-    def self.irb_original_method_name(method_name) # :nodoc:
-      "irb_" + method_name + "_org"
-    end
-
-    # Installs alias methods for the default irb commands on the given object
-    # using #install_alias_method.
-    def self.extend_object(obj)
-      unless (class << obj; ancestors; end).include?(EXCB)
-        super
-        for ali, com, flg in @ALIASES
-          obj.install_alias_method(ali, com, flg)
-        end
-      end
-    end
-
-    install_extend_commands
   end
 
   # Extends methods for the Context module
diff --git a/lib/irb/statement.rb b/lib/irb/statement.rb
index b12110600..4b15012b3 100644
--- a/lib/irb/statement.rb
+++ b/lib/irb/statement.rb
@@ -16,7 +16,7 @@ def should_be_handled_by_debugger?
       raise NotImplementedError
     end
 
-    def evaluable_code
+    def execute(context, line_no)
       raise NotImplementedError
     end
 
@@ -38,17 +38,16 @@ def is_assignment?
         @is_assignment
       end
 
-      def evaluable_code
-        @code
+      def execute(context, line_no)
+        context.evaluate(@code, line_no)
       end
     end
 
     class Command < Statement
-      def initialize(code, command, arg, command_class)
-        @code = code
-        @command = command
-        @arg = arg
+      def initialize(original_code, command_class, arg)
         @command_class = command_class
+        @arg = arg
+        @code = original_code
       end
 
       def is_assignment?
@@ -65,15 +64,9 @@ def should_be_handled_by_debugger?
         IRB::ExtendCommand::DebugCommand > @command_class || IRB::ExtendCommand::Help == @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(' ')
+      def execute(context, line_no)
+        ret = @command_class.execute(context, @arg)
+        context.set_last_value(ret)
       end
     end
   end
diff --git a/lib/irb/workspace.rb b/lib/irb/workspace.rb
index 2bf3d5e0f..a4256de3d 100644
--- a/lib/irb/workspace.rb
+++ b/lib/irb/workspace.rb
@@ -108,8 +108,11 @@ def initialize(*main)
     # <code>IRB.conf[:__MAIN__]</code>
     attr_reader :main
 
-    def load_commands_to_main
-      main.extend ExtendCommandBundle
+    def load_helper_methods_to_main
+      if ExtendCommandBundle.has_helper_method?
+        # Extend (== pollute) the main object for compatibility
+        main.extend ExtendCommandBundle
+      end
     end
 
     # Evaluate the given +statements+ within the  context of this workspace.