[ruby/irb] Remove dead code (https://github.com/ruby/irb/pull/554)

* Remove unused ATTR_TTY and ATTR_PLAIN constants

They were added in d7d26b51bf

But the references were removed in 1c76845cca

Co-authored-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

* Remove unused MethodExtender module

It was added in 6cc5d718d7
but it's not used anywhere.

Co-authored-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

* Remove unused IRB.irb_at_exit

It's not used after aaf4eb4e98

Co-authored-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

* Remove unused InputCompletor.ignored_modules

It was added in 88311ce3c8
but the reference was removed in 78c74d2425

* Remove unused TracerLoadError constant

This constant was added in cb50fa3738
but never referenced.

---------

https://github.com/ruby/irb/commit/7de0234325

Co-authored-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

lib/irb.rb

@@ -416,11 +416,6 @@ module IRB
     irb.run(@CONF)
   end
 
-  # Calls each event hook of <code>IRB.conf[:AT_EXIT]</code> when the current session quits.
-  def IRB.irb_at_exit
-    @CONF[:AT_EXIT].each{|hook| hook.call}
-  end
-
   # Quits irb
   def IRB.irb_exit(irb, ret)
     throw :IRB_EXIT, ret
@@ -897,11 +892,6 @@ module IRB
     ensure
       $VERBOSE = verbose
     end
-
-    ATTR_TTY = "\e[%sm"
-    def ATTR_TTY.[](*a) self % a.join(";"); end
-    ATTR_PLAIN = ""
-    def ATTR_PLAIN.[](*) self; end
   end
 
   def @CONF.inspect

lib/irb/completion.rb

@@ -450,30 +450,5 @@ module IRB
         end
       end
     end
-
-    def self.ignored_modules
-      # We could cache the result, but this is very fast already.
-      # By using this approach, we avoid Module#name calls, which are
-      # relatively slow when there are a lot of anonymous modules defined.
-      s = {}
-
-      scanner = lambda do |m|
-        next if s.include?(m) # IRB::ExtendCommandBundle::EXCB recurses.
-        s[m] = true
-        m.constants(false).each do |c|
-          value = m.const_get(c)
-          scanner.call(value) if value.is_a?(Module)
-        end
-      end
-
-      %i(IRB RubyLex).each do |sym|
-        next unless Object.const_defined?(sym)
-        scanner.call(Object.const_get(sym))
-      end
-
-      s.delete(IRB::Context) if defined?(IRB::Context)
-
-      s
-    end
   end
 end

lib/irb/ext/tracer.rb

@@ -9,7 +9,6 @@ begin
 rescue LoadError
   $stderr.puts "Tracer extension of IRB is enabled but tracer gem doesn't found."
   module IRB
-    TracerLoadError = true
     class Context
       def use_tracer=(opt)
         # do nothing

lib/irb/extend-command.rb

@@ -371,58 +371,4 @@ module IRB # :nodoc:
 
     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