Works in irb

lib/method_source.rb

@@ -6,6 +6,7 @@
 require "#{direc}/method_source/version"
 require "#{direc}/method_source/source_location"
 require "#{direc}/method_source/code_helpers"
+require "#{direc}/method_source/irb"
 
 module MethodSource
   extend MethodSource::CodeHelpers
@@ -49,6 +50,7 @@ def self.comment_helper(source_location, name=nil)
   # @return [Array<String>]  the contents of the file
   # @raise [SourceNotFoundError]
   def self.lines_for(file_name, name=nil)
+    return IRB.CurrentContext.source if file_name == "(irb)"
     @lines_for_file ||= {}
     @lines_for_file[file_name] ||= File.readlines(file_name)
   rescue Errno::ENOENT => e

lib/method_source/irb.rb

@@ -0,0 +1,24 @@
+# From the gem "cute_print", and before that from the gem "wrong"
+
+if defined? IRB
+  module IRB
+    class Context
+
+      def source
+        @all_lines.join
+      end
+
+      original_evaluate = instance_method(:evaluate)
+
+      # Save every line that is evaluated.  This gives a way to get
+      # the source when it is run in irb.
+      define_method :evaluate do |src, line_no|
+        @all_lines ||= []
+        @all_lines += ["\n"] * (line_no - @all_lines.size - 1)
+        @all_lines += src.lines.to_a
+        original_evaluate.bind(self).call src, line_no
+      end
+
+    end
+  end
+end

method_source.gemspec

@@ -22,6 +22,16 @@ Gem::Specification.new do |s|
     if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
       s.add_development_dependency(%q<bacon>, ["~> 1.1.0"])
       s.add_development_dependency(%q<rake>, ["~> 0.9"])
+      # Under some versions of Rubinius, when the tests are run with
+      # `bundle exec rake`, the irb tests failes with:
+      #     rubysl-irb is not part of the bundle. Add it to Gemfile.
+      # This seems to be a bug in some version of Rubinius:
+      #     https://gitter.im/rubinius/rubinius/archives/2015/04/14
+      # Since this is only a development dependency, we can get away
+      # with the the condition.
+      if Object.const_defined?("RUBY_ENGINE") && RUBY_ENGINE == 'rbx'
+        s.add_development_dependency(%q<rubysl-irb>)
+      end
     else
       s.add_dependency(%q<bacon>, ["~> 1.1.0"])
       s.add_dependency(%q<rake>, ["~> 0.9"])

test/test.rb

@@ -2,6 +2,7 @@
 
 require 'rubygems'
 require 'bacon'
+require 'shellwords'
 require "#{direc}/../lib/method_source"
 require "#{direc}/test_helper"
 
@@ -135,4 +136,21 @@ class << $o; self; end.instance_method(:hello).source.should == @hello_singleton
       method(:comment_test5).comment.should == @comment5
     end
   end
+
+  it "should work in irb" do
+    lib_path = File.join(File.dirname(__FILE__), "../lib")
+    command = [
+      "irb",
+      "-I", lib_path,
+    ].shelljoin
+    output = IO.popen(command, "r+") do |io|
+      io.puts 'require "method_source"'
+      io.puts 'l = lambda { }'
+      io.puts 'puts "l = #{l.source.inspect}"'
+      io.close_write
+      io.read
+    end
+    output.should.include 'l = "l = lambda { }\n"'
+  end
+
 end