add history to irbrc, use the simple prompt

irbrc

@@ -1,5 +1,48 @@
+require 'rubygems'
+require 'irb/completion'
+
+# Use awesome print for awesome output
 begin
-  require 'ap'
+  require 'awesome_print'
+
+  unless IRB.version.include?('DietRB')
+    IRB::Irb.class_eval do
+      def output_value
+        ap @context.last_value
+      end
+    end
+  else # MacRuby
+    IRB.formatter = Class.new(IRB::Formatter) do
+      def inspect_object(object)
+        object.ai
+      end
+    end.new
+  end
 rescue LoadError => e
   puts "!! Failed to load awesome print."
 end
+
+# Use the simple prompt if possible.
+IRB.conf[:PROMPT_MODE] = :SIMPLE if IRB.conf[:PROMPT_MODE] == :DEFAULT
+
+# Setup permanent history.
+HISTFILE = "~/.irb_history"
+MAXHISTSIZE = 10000
+begin
+  histfile = File::expand_path(HISTFILE)
+  if File::exists?(histfile)
+    lines = IO::readlines(histfile).collect { |line| line.chomp }
+    puts "Read #{lines.length} saved history commands from '#{histfile}'." if $VERBOSE
+    Readline::HISTORY.push(*lines)
+  else
+    puts "History file '#{histfile}' was empty or non-existant." if $VERBOSE
+  end
+  Kernel::at_exit do
+    lines = Readline::HISTORY.to_a.reverse.uniq.reverse
+    lines = lines[-MAXHISTSIZE, MAXHISTSIZE] if lines.length > MAXHISTSIZE
+    puts "Saving #{lines.length} history lines to '#{histfile}'." if $VERBOSE
+    File::open(histfile, File::WRONLY|File::CREAT|File::TRUNC) { |io| io.puts lines.join("\n") }
+  end
+rescue => e
+  puts "Error when configuring permanent history: #{e}" if $VERBOSE
+end