From 2895bb245fd216be96da6e4d6b9e361248934450 Mon Sep 17 00:00:00 2001
From: John Mair <jrmair@gmail.com>
Date: Fri, 17 Dec 2010 02:58:01 +1300
Subject: first commit

---
 .yardopts                    |  1 +
 README.markdown              | 48 ++++++++++++++++++++++
 Rakefile                     | 57 +++++++++++++++++++++++++++
 lib/method_source.rb         | 94 ++++++++++++++++++++++++++++++++++++++++++++
 lib/method_source/version.rb |  3 ++
 test/test.rb                 | 32 +++++++++++++++
 6 files changed, 235 insertions(+)
 create mode 100644 .yardopts
 create mode 100644 README.markdown
 create mode 100644 Rakefile
 create mode 100644 lib/method_source.rb
 create mode 100644 lib/method_source/version.rb
 create mode 100644 test/test.rb

diff --git a/.yardopts b/.yardopts
new file mode 100644
index 0000000..a4e7838
--- /dev/null
+++ b/.yardopts
@@ -0,0 +1 @@
+-m markdown 
diff --git a/README.markdown b/README.markdown
new file mode 100644
index 0000000..0d73f38
--- /dev/null
+++ b/README.markdown
@@ -0,0 +1,48 @@
+method_source
+=============
+
+(C) John Mair (banisterfiend) 2010
+
+_retrieve the sourcecode for a method_
+
+`method_source` is a utility to return a method's sourcecode as a
+Ruby string.
+
+It is written in pure Ruby (no C).
+
+`method_source` provides the `source` method to the `Method` and
+`UnboundMethod` classes.
+
+* Install the [gem](https://rubygems.org/gems/method_source): `gem install method_source`
+* Read the [documentation](http://rdoc.info/github/banister/method_source/master/file/README.markdown)
+* See the [source code](http://github.com/banister/method_source)
+
+example: 
+---------
+
+    Set.instance_method(:merge).source.display
+    # =>
+    def merge(enum)
+      if enum.instance_of?(self.class)
+        @hash.update(enum.instance_variable_get(:@hash))
+      else
+        do_with_enum(enum) { |o| add(o) }
+      end
+
+      self
+    end
+
+Limitations:
+------------
+
+* Only works with Ruby 1.9+
+* Cannot return source for C methods.
+* Cannot return source for dynamically defined methods.
+
+Possible Applications:
+----------------------
+
+* Combine with [RubyParser](https://github.com/seattlerb/ruby_parser)
+  for extra fun.
+
+
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..4edeaac
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,57 @@
+dlext = Config::CONFIG['DLEXT']
+direc = File.dirname(__FILE__)
+
+require 'rake/clean'
+require 'rake/gempackagetask'
+require "#{direc}/lib/method_source/version"
+
+CLOBBER.include("**/*.#{dlext}", "**/*~", "**/*#*", "**/*.log", "**/*.o")
+CLEAN.include("ext/**/*.#{dlext}", "ext/**/*.log", "ext/**/*.o",
+              "ext/**/*~", "ext/**/*#*", "ext/**/*.obj",
+              "ext/**/*.def", "ext/**/*.pdb", "**/*_flymake*.*", "**/*_flymake")
+
+def apply_spec_defaults(s)
+  s.name = "method_source"
+  s.summary = "retrieve the sourcecode for a method"
+  s.version = MethodSource::VERSION
+  s.date = Time.now.strftime '%Y-%m-%d'
+  s.author = "John Mair (banisterfiend)"
+  s.email = 'jrmair@gmail.com'
+  s.description = s.summary
+  s.require_path = 'lib'
+  s.homepage = "http://banisterfiend.wordpress.com"
+  s.has_rdoc = 'yard'
+  s.files = Dir["ext/**/extconf.rb", "ext/**/*.h", "ext/**/*.c", "lib/**/*.rb",
+                     "test/*.rb", "CHANGELOG", "README.markdown", "Rakefile"]
+end
+
+task :test do
+  sh "bacon -k #{direc}/test/test.rb"
+end
+
+namespace :ruby do
+  spec = Gem::Specification.new do |s|
+    apply_spec_defaults(s)        
+    s.platform = Gem::Platform::RUBY
+  end
+  
+  Rake::GemPackageTask.new(spec) do |pkg|
+    pkg.need_zip = false
+    pkg.need_tar = false
+  end
+end
+
+desc "build all platform gems at once"
+task :gems => [:rmgems, "ruby:gem"]
+
+desc "remove all platform gems"
+task :rmgems => ["ruby:clobber_package"]
+
+desc "build and push latest gems"
+task :pushgems => :gems do
+  chdir("#{direc}/pkg") do
+    Dir["*.gem"].each do |gemfile|
+      sh "gem push #{gemfile}"
+    end
+  end
+end
diff --git a/lib/method_source.rb b/lib/method_source.rb
new file mode 100644
index 0000000..bdb00ed
--- /dev/null
+++ b/lib/method_source.rb
@@ -0,0 +1,94 @@
+# (C) John Mair (banisterfiend) 2010
+# MIT License
+
+direc = File.dirname(__FILE__)
+
+require 'stringio'
+require "#{direc}/method_source/version"
+
+module MethodSource
+
+  # Helper method used to find end of method body
+  # @param [String] code The string of Ruby code to check for
+  # correctness
+  # @return [Boolean] 
+  def self.valid_expression?(code)
+    suppress_stderr do
+      RubyVM::InstructionSequence.new(code)
+    end
+  rescue Exception
+    false
+  else
+    true
+  end
+
+  # Helper method used to suppress stderr output by the
+  # `RubyVM::InstructionSequence` method
+  # @yield The block where stderr is suppressed
+  def self.suppress_stderr
+    real_stderr, $stderr = $stderr, StringIO.new
+    yield
+  ensure
+    $stderr = real_stderr
+  end
+
+  # Helper method responsible for opening source file and advancing to
+  # the correct linenumber. Defined here to avoid polluting `Method`
+  # class.
+  # @param [Array] source_location The array returned by Method#source_location
+  # @return [File] The opened source file
+  def self.source_helper(source_location)
+    return nil if !source_location.is_a?(Array)
+    
+    file_name, line = source_location
+    file = File.open(file_name)
+    (line - 1).times { file.readline }
+    file
+  end
+  
+  # This module is to be included by `Method` and `UnboundMethod` and
+  # provides the `#source` functionality
+  module MethodExtensions
+    
+    # Return the sourcecode for the method as a string
+    # (This functionality is only supported in Ruby 1.9 and above)
+    # @return [String] The method sourcecode as a string
+    # @example
+    #  Set.instance_method(:clear).source.display
+    #  =>
+    #     def clear
+    #       @hash.clear
+    #       self
+    #     end
+    def source
+      file = nil
+      
+      if respond_to?(:source_location)
+        file = MethodSource.source_helper(source_location)
+        
+        raise "Cannot locate source for this method: #{name}" if !file
+      else
+        raise "Method#source not supported by this Ruby version (#{RUBY_VERSION})"
+      end
+
+      code = ""
+      loop do
+        val = file.readline
+        code += val
+        
+        return code if MethodSource.valid_expression?(code)
+      end
+      
+    ensure
+      file.close if file
+    end
+  end
+end
+
+class Method
+  include MethodSource::MethodExtensions
+end
+
+class UnboundMethod
+  include MethodSource::MethodExtensions
+end
diff --git a/lib/method_source/version.rb b/lib/method_source/version.rb
new file mode 100644
index 0000000..30c0683
--- /dev/null
+++ b/lib/method_source/version.rb
@@ -0,0 +1,3 @@
+module MethodSource
+  VERSION = "0.1.0"
+end
diff --git a/test/test.rb b/test/test.rb
new file mode 100644
index 0000000..8a4beaa
--- /dev/null
+++ b/test/test.rb
@@ -0,0 +1,32 @@
+direc = File.dirname(__FILE__)
+
+require 'bacon'
+require "#{direc}/../lib/method_source"
+
+hello_source = "def hello; :hello; end\n"
+
+def hello; :hello; end
+
+describe MethodSource do
+
+  it 'should define methods on both Method and UnboundMethod' do
+    Method.method_defined?(:source).should == true
+    UnboundMethod.method_defined?(:source).should == true
+  end
+  
+  if RUBY_VERSION =~ /1.9/
+    it 'should return source for method' do
+      method(:hello).source.should == hello_source
+    end
+
+    it 'should raise for C methods' do
+      lambda { method(:puts).source }.should.raise RuntimeError
+    end
+
+  else
+    it 'should raise on #source' do
+      lambda { method(:hello).source }.should.raise RuntimeError
+    end
+  end
+end
+
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