Diff + tests

Author: espadrine

.rspec

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+--color

Gemfile

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+source "http://rubygems.org"
+gemspec
+
+group :test do
+  gem 'rake'
+end

LICENSE

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+Copyright (c) 2015 Captain Train
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+

Makefile

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+install:
+	gem build json-diff.gemspec && sudo gem install ./json-diff-*.gem
+
+.PHONY: install

README.md

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+# `json-diff`
+
+*Take two Ruby objects that can be serialized to JSON. Output an array of operations (additions, deletions, moves) that would convert the first one to the second one.*
+
+```bash
+gem install json-diff  # Or `gem 'json-diff'` in your Gemfile.
+```
+
+```ruby
+require 'json-diff'
+JsonDiff.diff(1, 2)
+#> [{:op => :replace, :path => "/", :value => 2}]
+```
+
+Outputs [RFC6902][]. Look at [hana][] for a JSON patch algorithm that can use this output.
+
+[RFC6902]: http://www.rfc-editor.org/rfc/rfc6902.txt
+[hana]: https://github.com/tenderlove/hana
+
+# Heart
+
+- Recursive similarity computation between any two Ruby values.
+- For arrays, match elements above a certain level of similarity pairwise, and treat them as a move.
+  - Matching happens highest-similarity first.
+  - The creation of move operations is generated by detecting rings in the list of moved elements (eg, A → B → C → A).
+
+Pros:
+
+- For lists which are not necessarily ordered, this approach yields far better results than LCS.
+- Move operations require no custom code to match elements.
+
+Cons:
+
+- This approach's quality is heavily reliant on how good the similarity algorithm is. Empirically, it yields sensible output. It can be improved by a user-defined procedure.
+- There is a computational overhead to the default similarity computation that scales with the total number of entities in the structure.
+
+# Plans & Bugs
+
+Roughly ordered by priority.
+
+- Support adding a custom procedure which computes similarities.
+- Support LCS as an option. (The default will remain what yields the best results, regardless of the time it takes.)
+- Support specifying a depth for similarity computation.
+
+---
+
+See the LICENSE file for licensing information.

Rakefile

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+$:.push File.expand_path("../lib", __FILE__)
+
+require 'bundler'
+Bundler::GemHelper.install_tasks
+
+require 'rspec/core/rake_task'
+RSpec::Core::RakeTask.new(:spec)
+
+task default: :spec

json-diff.gemspec

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+$LOAD_PATH.push File.expand_path('../lib', __FILE__)
+require 'json-diff/version'
+
+Gem::Specification.new do |s|
+  s.name        = 'json-diff'
+  s.license     = 'MIT'
+  s.version     = JsonDiff::VERSION
+  s.platform    = Gem::Platform::RUBY
+  s.authors     = ['Captain Train']
+  s.email       = ['[email protected]']
+  s.homepage    = 'http://github.com/captaintrain/json-diff'
+  s.summary     = %q{Compute the difference between two JSON-serializable Ruby objects.}
+  s.description = %q{Take two Ruby objects that can be serialized to JSON. Output an array of operations (additions, deletions, moves) that would convert the first one to the second one.}
+  s.files       = `git ls-files`.split("\n")
+end

lib/json-diff.rb

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+require 'json-diff/diff'
+require 'json-diff/index-map'
+require 'json-diff/operation'
+require 'json-diff/version'