Adds a function for computing permutations and its corresponding unit…

… tests

.gitignore

@@ -4,3 +4,5 @@ coffeescript/node_modules/*
 java/build/*
 java/.gradle/*
 .sass-cache/*
+npm-debug.log
+docs/*

LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Dylon Edwards
+
+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.

coffeescript/Cakefile

@@ -0,0 +1,37 @@
+require 'coffee-script/register' #-> Register the .coffee extension
+
+fs            = require 'fs'
+{print}       = require 'sys'
+{spawn, exec} = require 'child_process'
+
+build = (watch, callback) ->
+  if typeof watch is 'function'
+    callback = watch
+    watch = false
+  options = ['-b', '-c', '-o', 'lib', 'src']
+  options.unshift '-w' if watch
+
+  coffee = spawn 'coffee', options
+  coffee.stdout.on 'data', (data) -> print data.toString()
+  coffee.stderr.on 'data', (data) -> print data.toString()
+  coffee.on 'exit', (status) -> callback?() if status is 0
+
+task 'docs', 'Generate annotated source code with Docco', ->
+  fs.readdir 'src', (err, contents) ->
+    files = ("src/#{file}" for file in contents when /\.coffee$/.test file)
+    docco = spawn 'docco', files
+    docco.stdout.on 'data', (data) -> print data.toString()
+    docco.stderr.on 'data', (data) -> print data.toString()
+    docco.on 'exit', (status) -> callback?() if status is 0
+
+task 'build', 'Compile CoffeeScript source files', ->
+  build()
+
+task 'watch', 'Recompile CoffeeScript source files when modified', ->
+  build true
+
+task 'test', 'Run the test suite', ->
+  build ->
+    {reporters} = require 'nodeunit'
+    process.chdir __dirname
+    reporters.default.run ['test']

coffeescript/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "liblevenshtein",
+  "description": "Various utilities regarding Levenshtein transducers.",
+  "author": "Dylon Edwards",
+  "version": "2.0.0",
+  "licenses": [
+    {
+      "type": "MIT",
+      "url": "https://github.com/dylon/liblevenshtein/raw/master/LICENSE"
+    }
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/dylon/liblevenshtein.git"
+  },
+  "main": null,
+  "devDependencies": {
+    "nodeunit": "~0.8",
+    "coffee-script": "~1.7"
+  },
+  "engines":
+  {
+    "node": "~0.10"
+  }
+}

coffeescript/src/permutations.coffee

@@ -0,0 +1,44 @@
+global =
+  if typeof exports is 'object'
+    exports
+  else if typeof window is 'object'
+    window
+  else
+    this
+
+concat = (lists...) ->
+  concatenation = []
+  (concatenation = concatenation.concat(list)) for list in lists
+  concatenation
+
+expand = (element, lists) ->
+  list.unshift(element) for list in lists
+  lists
+
+swap = (list, i, j) ->
+  t = list[i]
+  list[i] = list[j]
+  list[j] = t
+  list
+
+permutations = (list, i) ->
+  switch list.length - i
+    when 0
+      []
+    when 1
+      [[list[i]]]
+    when 2
+      [
+        [list[i], list[i + 1]]
+        [list[i + 1], list[i]]
+      ]
+    else
+      p = []
+      offset = list.length - i
+      for j in [0...offset]
+        l = list.slice()
+        swap(l, i, i + j)
+        p.push(expand(l[i], permutations(l, i + 1)))
+      concat.apply(null, p)
+
+global.permutations = (list) -> permutations(list, 0)

coffeescript/test/permutations.coffee

@@ -0,0 +1,178 @@
+{permutations} = require '../src/permutations'
+
+module.exports =
+  'There should be no permutations on an empty list': (test) ->
+    test.deepEqual(permutations([]), [])
+    test.done()
+  'The only permutation on a singleton list should be the same list': (test) ->
+    test.deepEqual(permutations([1]), [[1]])
+    test.done()
+  'There should be 2-factorial, distinct permutations on a pair': (test) ->
+    test.deepEqual(permutations([1,2]),[
+      [1,2]
+      [2,1]
+    ])
+    test.done()
+  'There should be 3-factorial, distinct permutations on a triple': (test) ->
+    test.deepEqual(permutations([1..3]), [
+      [1, 2, 3]
+      [1, 3, 2]
+      [2, 1, 3]
+      [2, 3, 1]
+      [3, 2, 1]
+      [3, 1, 2]
+    ])
+    test.done()
+  'There should be 4-factorial, distinct permutations on a quadruple': (test) ->
+    test.deepEqual(permutations([1..4]), [
+      [1, 2, 3, 4]
+      [1, 2, 4, 3]
+      [1, 3, 2, 4]
+      [1, 3, 4, 2]
+      [1, 4, 3, 2]
+      [1, 4, 2, 3]
+      [2, 1, 3, 4]
+      [2, 1, 4, 3]
+      [2, 3, 1, 4]
+      [2, 3, 4, 1]
+      [2, 4, 3, 1]
+      [2, 4, 1, 3]
+      [3, 2, 1, 4]
+      [3, 2, 4, 1]
+      [3, 1, 2, 4]
+      [3, 1, 4, 2]
+      [3, 4, 1, 2]
+      [3, 4, 2, 1]
+      [4, 2, 3, 1]
+      [4, 2, 1, 3]
+      [4, 3, 2, 1]
+      [4, 3, 1, 2]
+      [4, 1, 3, 2]
+      [4, 1, 2, 3]
+    ])
+    test.done()
+  'There should be 5-factorial, distinct permutations on a 5-tuple': (test) ->
+    test.deepEqual(permutations([1..5]), [
+      [1, 2, 3, 4, 5]
+      [1, 2, 3, 5, 4]
+      [1, 2, 4, 3, 5]
+      [1, 2, 4, 5, 3]
+      [1, 2, 5, 4, 3]
+      [1, 2, 5, 3, 4]
+      [1, 3, 2, 4, 5]
+      [1, 3, 2, 5, 4]
+      [1, 3, 4, 2, 5]
+      [1, 3, 4, 5, 2]
+      [1, 3, 5, 4, 2]
+      [1, 3, 5, 2, 4]
+      [1, 4, 3, 2, 5]
+      [1, 4, 3, 5, 2]
+      [1, 4, 2, 3, 5]
+      [1, 4, 2, 5, 3]
+      [1, 4, 5, 2, 3]
+      [1, 4, 5, 3, 2]
+      [1, 5, 3, 4, 2]
+      [1, 5, 3, 2, 4]
+      [1, 5, 4, 3, 2]
+      [1, 5, 4, 2, 3]
+      [1, 5, 2, 4, 3]
+      [1, 5, 2, 3, 4]
+      [2, 1, 3, 4, 5]
+      [2, 1, 3, 5, 4]
+      [2, 1, 4, 3, 5]
+      [2, 1, 4, 5, 3]
+      [2, 1, 5, 4, 3]
+      [2, 1, 5, 3, 4]
+      [2, 3, 1, 4, 5]
+      [2, 3, 1, 5, 4]
+      [2, 3, 4, 1, 5]
+      [2, 3, 4, 5, 1]
+      [2, 3, 5, 4, 1]
+      [2, 3, 5, 1, 4]
+      [2, 4, 3, 1, 5]
+      [2, 4, 3, 5, 1]
+      [2, 4, 1, 3, 5]
+      [2, 4, 1, 5, 3]
+      [2, 4, 5, 1, 3]
+      [2, 4, 5, 3, 1]
+      [2, 5, 3, 4, 1]
+      [2, 5, 3, 1, 4]
+      [2, 5, 4, 3, 1]
+      [2, 5, 4, 1, 3]
+      [2, 5, 1, 4, 3]
+      [2, 5, 1, 3, 4]
+      [3, 2, 1, 4, 5]
+      [3, 2, 1, 5, 4]
+      [3, 2, 4, 1, 5]
+      [3, 2, 4, 5, 1]
+      [3, 2, 5, 4, 1]
+      [3, 2, 5, 1, 4]
+      [3, 1, 2, 4, 5]
+      [3, 1, 2, 5, 4]
+      [3, 1, 4, 2, 5]
+      [3, 1, 4, 5, 2]
+      [3, 1, 5, 4, 2]
+      [3, 1, 5, 2, 4]
+      [3, 4, 1, 2, 5]
+      [3, 4, 1, 5, 2]
+      [3, 4, 2, 1, 5]
+      [3, 4, 2, 5, 1]
+      [3, 4, 5, 2, 1]
+      [3, 4, 5, 1, 2]
+      [3, 5, 1, 4, 2]
+      [3, 5, 1, 2, 4]
+      [3, 5, 4, 1, 2]
+      [3, 5, 4, 2, 1]
+      [3, 5, 2, 4, 1]
+      [3, 5, 2, 1, 4]
+      [4, 2, 3, 1, 5]
+      [4, 2, 3, 5, 1]
+      [4, 2, 1, 3, 5]
+      [4, 2, 1, 5, 3]
+      [4, 2, 5, 1, 3]
+      [4, 2, 5, 3, 1]
+      [4, 3, 2, 1, 5]
+      [4, 3, 2, 5, 1]
+      [4, 3, 1, 2, 5]
+      [4, 3, 1, 5, 2]
+      [4, 3, 5, 1, 2]
+      [4, 3, 5, 2, 1]
+      [4, 1, 3, 2, 5]
+      [4, 1, 3, 5, 2]
+      [4, 1, 2, 3, 5]
+      [4, 1, 2, 5, 3]
+      [4, 1, 5, 2, 3]
+      [4, 1, 5, 3, 2]
+      [4, 5, 3, 1, 2]
+      [4, 5, 3, 2, 1]
+      [4, 5, 1, 3, 2]
+      [4, 5, 1, 2, 3]
+      [4, 5, 2, 1, 3]
+      [4, 5, 2, 3, 1]
+      [5, 2, 3, 4, 1]
+      [5, 2, 3, 1, 4]
+      [5, 2, 4, 3, 1]
+      [5, 2, 4, 1, 3]
+      [5, 2, 1, 4, 3]
+      [5, 2, 1, 3, 4]
+      [5, 3, 2, 4, 1]
+      [5, 3, 2, 1, 4]
+      [5, 3, 4, 2, 1]
+      [5, 3, 4, 1, 2]
+      [5, 3, 1, 4, 2]
+      [5, 3, 1, 2, 4]
+      [5, 4, 3, 2, 1]
+      [5, 4, 3, 1, 2]
+      [5, 4, 2, 3, 1]
+      [5, 4, 2, 1, 3]
+      [5, 4, 1, 2, 3]
+      [5, 4, 1, 3, 2]
+      [5, 1, 3, 4, 2]
+      [5, 1, 3, 2, 4]
+      [5, 1, 4, 3, 2]
+      [5, 1, 4, 2, 3]
+      [5, 1, 2, 4, 3]
+      [5, 1, 2, 3, 4]
+    ])
+    test.done()
+