Inverted diff, or a mode like comm

README.md

@@ -1,29 +1,37 @@
 # Yamldiff
 [![Build Status](https://travis-ci.org/wallace/yamldiff.png)](https://travis-ci.org/wallace/yamldiff)
 
-Given two yaml files, Yamldiff tells you which keys present in the first file
-are not present in the second.
+Given two yaml files, Yamldiff tells you which keys present in the first file are not present in the second.
 
 ## Installation
 
-Add this line to your application's Gemfile:
+From release:
+```bash
+$ sudo gem install yamldiff
+```
 
-    gem 'yamldiff'
-
-And then execute:
-
-    $ bundle
-
-Or install it yourself as:
-
-    $ gem install yamldiff
+From source code:
+```bash
+$ bundle
+$ gem build yamldiff.gemspec
+$ sudo gem install yamldiff-VERSION.gem
+```
 
 ## Usage
 
-    require 'yamldiff'
-    result = Yamldiff.diff_yaml('path_to_file_1', 'path_to_file_2')
-    result.inspect
-    # { 'path_to_file_2' => [<array of YamldiffError objects>] }
+Of the program:
+```console
+$ yamldiff 
+USAGE: yamldiff [-i] file1 file2
+```
+
+Of the lib:
+```ruby
+require 'yamldiff'
+result = Yamldiff.diff_yaml('path_to_file_1', 'path_to_file_2')
+result.inspect
+# { 'path_to_file_2' => [<array of YamldiffError objects>] }
+```
 
 ## Contributing
 

bin/yamldiff

@@ -2,11 +2,22 @@
 
 $LOAD_PATH.unshift(File.expand_path("../../lib", __FILE__))
 require 'yamldiff'
+require 'set'
 
-if ARGV.size != 2
-  $stderr.puts "USAGE: yamldiff file1 file2"
+if ARGV.size != 2 && !(ARGV.size == 3 &&  ARGV[0] == "-i")
+  $stderr.puts "USAGE: yamldiff [-i] file1 file2"
   exit 1
 end
 
-errors = Yamldiff.diff_yaml(ARGV[0], ARGV[1])
-puts errors[ARGV[1]]
+if ARGV.size == 3
+  begin
+    ignore = Set.new File.readlines(ARGV[2] + ".ignore").map(&:chomp)
+    common = Set.new Yamlcomm.comm_yaml(ARGV[1], ARGV[2])
+    puts (common - ignore).to_a()
+  rescue Errno::ENOENT
+    puts Yamlcomm.comm_yaml(ARGV[1], ARGV[2])
+  end
+else
+  errors = Yamldiff.diff_yaml(ARGV[0], ARGV[1])
+  puts errors[ARGV[1]]
+end

lib/yamldiff/version.rb

@@ -1,3 +1,3 @@
 class Yamldiff
-  VERSION = "0.0.9"
+  VERSION = "0.0.10"
 end

lib/yamldiff/yamldiff.rb

@@ -44,3 +44,46 @@ def compare_hashes(first, second, context = [])
     end
   end
 end
+
+class Yamlcomm
+  class << self
+    # Compare the two yaml files
+    def comm_yaml(first, second, common = [])
+      primary            = YAML.load(ERB.new(File.read(first)).result)
+      secondary          = YAML.load(ERB.new(File.read(second)).result)
+      common = compare_hashes(primary, secondary)
+      common
+    end
+
+    # Adapted from yamldiff.rb
+    def compare_hashes(first, second, context = [])
+      common = []
+
+      first.each do |key, value|
+
+        unless second
+          next
+        end
+
+        if value.is_a?(Hash)
+          common << compare_hashes(value, second[key], context + [key])
+          next
+        end
+
+        if second.key?(key)
+          value2 = second[key]
+          if value.class == value2.class
+            if value == value2
+              s = ""
+              context.each { |p| s += p + "." }
+              common << s + key
+            end
+          end
+        end
+
+      end
+
+      common.flatten
+    end
+  end
+end