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Filename : extend-command.rb
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#
#   irb/extend-command.rb - irb extend command
#   	$Release Version: 0.9.6$
#   	$Revision: 38515 $
#   	by Keiju ISHITSUKA(keiju@ruby-lang.org)
#
# --
#
#
#
module IRB # :nodoc:
  # Installs the default irb extensions command bundle.
  module ExtendCommandBundle
    EXCB = ExtendCommandBundle # :nodoc:

    # See #install_alias_method.
    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.
    #
    # Modifing 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_current_working_workspace, :CurrentWorkingWorkspace, "irb/cmd/chws",
	[:irb_print_working_workspace, OVERRIDE_ALL],
	[:irb_cwws, OVERRIDE_ALL],
	[:irb_pwws, OVERRIDE_ALL],
#	[:irb_cww, OVERRIDE_ALL],
#	[:irb_pww, OVERRIDE_ALL],
	[:cwws, NO_OVERRIDE],
	[:pwws, NO_OVERRIDE],
#	[:cww, NO_OVERRIDE],
#	[:pww, NO_OVERRIDE],
	[:irb_current_working_binding, OVERRIDE_ALL],
	[:irb_print_working_binding, OVERRIDE_ALL],
	[:irb_cwb, OVERRIDE_ALL],
	[:irb_pwb, OVERRIDE_ALL],
#	[:cwb, NO_OVERRIDE],
#	[:pwb, NO_OVERRIDE]
      ],
      [:irb_change_workspace, :ChangeWorkspace, "irb/cmd/chws",
	[:irb_chws, OVERRIDE_ALL],
#	[:irb_chw, OVERRIDE_ALL],
	[:irb_cws, OVERRIDE_ALL],
#	[:irb_cw, OVERRIDE_ALL],
	[:chws, NO_OVERRIDE],
#	[:chw, NO_OVERRIDE],
	[:cws, NO_OVERRIDE],
#	[:cw, NO_OVERRIDE],
	[:irb_change_binding, OVERRIDE_ALL],
	[:irb_cb, OVERRIDE_ALL],
	[:cb, NO_OVERRIDE]],

      [:irb_workspaces, :Workspaces, "irb/cmd/pushws",
	[:workspaces, NO_OVERRIDE],
	[:irb_bindings, OVERRIDE_ALL],
	[:bindings, NO_OVERRIDE]],
      [:irb_push_workspace, :PushWorkspace, "irb/cmd/pushws",
	[:irb_pushws, OVERRIDE_ALL],
#	[:irb_pushw, OVERRIDE_ALL],
	[:pushws, NO_OVERRIDE],
#	[:pushw, NO_OVERRIDE],
	[:irb_push_binding, OVERRIDE_ALL],
	[:irb_pushb, OVERRIDE_ALL],
	[:pushb, NO_OVERRIDE]],
      [:irb_pop_workspace, :PopWorkspace, "irb/cmd/pushws",
	[:irb_popws, OVERRIDE_ALL],
#	[:irb_popw, OVERRIDE_ALL],
	[:popws, NO_OVERRIDE],
#	[:popw, NO_OVERRIDE],
	[:irb_pop_binding, OVERRIDE_ALL],
	[:irb_popb, OVERRIDE_ALL],
	[:popb, NO_OVERRIDE]],

      [:irb_load, :Load, "irb/cmd/load"],
      [:irb_require, :Require, "irb/cmd/load"],
      [:irb_source, :Source, "irb/cmd/load",
	[:source, NO_OVERRIDE]],

      [:irb, :IrbCommand, "irb/cmd/subirb"],
      [:irb_jobs, :Jobs, "irb/cmd/subirb",
	[:jobs, NO_OVERRIDE]],
      [:irb_fg, :Foreground, "irb/cmd/subirb",
	[:fg, NO_OVERRIDE]],
      [:irb_kill, :Kill, "irb/cmd/subirb",
	[:kill, OVERRIDE_PRIVATE_ONLY]],

      [:irb_help, :Help, "irb/cmd/help",
        [:help, NO_OVERRIDE]],

    ]

    # Installs the default irb commands:
    #
    # +irb_current_working_workspace+::   Context#main
    # +irb_change_workspace+::            Context#change_workspace
    # +irb_workspaces+::                  Context#workspaces
    # +irb_push_workspace+::              Context#push_workspace
    # +irb_pop_workspace+::               Context#pop_workspace
    # +irb_load+::                        #irb_load
    # +irb_require+::                     #irb_require
    # +irb_source+::                      IrbLoader#source_file
    # +irb+::                             IRB.irb
    # +irb_jobs+::                        JobManager
    # +irb_fg+::                          JobManager#switch
    # +irb_kill+::                        JobManager#kill
    # +irb_help+::                        IRB@Command+line+options
    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 = nil, *aliases)
      case cmd_class
      when Symbol
	cmd_class = cmd_class.id2name
      when String
      when Class
	cmd_class = cmd_class.name
      end

      if load_file
	line = __LINE__; eval %[
	  def #{cmd_name}(*opts, &b)
	    require "#{load_file}"
	    arity = ExtendCommand::#{cmd_class}.instance_method(:execute).arity
	    args = (1..(arity < 0 ? ~arity : arity)).map {|i| "arg" + i.to_s }
	    args << "*opts" if arity < 0
	    args << "&block"
	    args = args.join(", ")
	    line = __LINE__; eval %[
	      def #{cmd_name}(\#{args})
		ExtendCommand::#{cmd_class}.execute(irb_context, \#{args})
	      end
	    ], nil, __FILE__, line
	    send :#{cmd_name}, *opts, &b
	  end
	], nil, __FILE__, line
      else
	line = __LINE__; eval %[
	  def #{cmd_name}(*opts, &b)
	    ExtendCommand::#{cmd_class}.execute(irb_context, *opts, &b)
	  end
	], nil, __FILE__, line
      end

      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
	print "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
  module ContextExtender
    CE = ContextExtender # :nodoc:

    @EXTEND_COMMANDS = [
      [:eval_history=, "irb/ext/history.rb"],
      [:use_tracer=, "irb/ext/tracer.rb"],
      [:math_mode=, "irb/ext/math-mode.rb"],
      [:use_loader=, "irb/ext/use-loader.rb"],
      [:save_history=, "irb/ext/save-history.rb"],
    ]

    # Installs the default context extensions as irb commands:
    #
    # Context#eval_history=::   +irb/ext/history.rb+
    # Context#use_tracer=::     +irb/ext/tracer.rb+
    # Context#math_mode=::      +irb/ext/math-mode.rb+
    # Context#use_loader=::     +irb/ext/use-loader.rb+
    # Context#save_history=::   +irb/ext/save-history.rb+
    def self.install_extend_commands
      for args in @EXTEND_COMMANDS
	def_extend_command(*args)
      end
    end

    # Evaluate the given +command+ from the given +load_file+ on the Context
    # module.
    #
    # Will also define any given +aliases+ for the method.
    def self.def_extend_command(cmd_name, load_file, *aliases)
      line = __LINE__; Context.module_eval %[
        def #{cmd_name}(*opts, &b)
	  Context.module_eval {remove_method(:#{cmd_name})}
	  require "#{load_file}"
	  send :#{cmd_name}, *opts, &b
	end
	for ali in aliases
	  alias_method ali, cmd_name
	end
      ], __FILE__, line
    end

    CE.install_extend_commands
  end

  # A convenience module for extending Ruby methods.
  module MethodExtender
    # Extends the given +base_method+ with a prefix call to the given
    # +extend_method+.
    def def_pre_proc(base_method, extend_method)
      base_method = base_method.to_s
      extend_method = extend_method.to_s

      alias_name = new_alias_name(base_method)
      module_eval %[
        alias_method alias_name, base_method
        def #{base_method}(*opts)
	  send :#{extend_method}, *opts
	  send :#{alias_name}, *opts
	end
      ]
    end

    # Extends the given +base_method+ with a postfix call to the given
    # +extend_method+.
    def def_post_proc(base_method, extend_method)
      base_method = base_method.to_s
      extend_method = extend_method.to_s

      alias_name = new_alias_name(base_method)
      module_eval %[
        alias_method alias_name, base_method
        def #{base_method}(*opts)
	  send :#{alias_name}, *opts
	  send :#{extend_method}, *opts
	end
      ]
    end

    # Returns a unique method name to use as an alias for the given +name+.
    #
    # Usually returns <code>#{prefix}#{name}#{postfix}<num></code>, example:
    #
    #     new_alias_name('foo') #=> __alias_of__foo__
    #     def bar; end
    #     new_alias_name('bar') #=> __alias_of__bar__2
    def new_alias_name(name, prefix = "__alias_of__", postfix = "__")
      base_name = "#{prefix}#{name}#{postfix}"
      all_methods = instance_methods(true) + private_instance_methods(true)
      same_methods = all_methods.grep(/^#{Regexp.quote(base_name)}[0-9]*$/)
      return base_name if same_methods.empty?
      no = same_methods.size
      while !same_methods.include?(alias_name = base_name + no)
	no += 1
      end
      alias_name
    end
  end
end