Initial version.

.travis.yml

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+language: node_js
+node_js:
+  - 0.4
+  - 0.5
+  - 0.6

History.md

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+# Changes
+
+## 0.0.1 / 2012-12-25
+
+  - Initial release

License.md

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+Copyright 2012 Irakli Gozalishvili. All rights reserved.
+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.

Readme.md

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+# variator
+
+[![Build Status](https://secure.travis-ci.org/Gozala/variator.png)](http://travis-ci.org/Gozala/variator)
+
+Prefix based method dispatch is an extendable alternative to imperative
+[switch][] statements.
+
+## Usage
+
+
+```js
+var variator = require("variator")
+var price = variator("price")
+
+price.define("Oranges", function(fruit, pound) {
+  var n = pound || 1
+  return "Total price for " + fruit + " is $" + n * 0.59
+})
+price.define("Apples", function(fruit, pound) {
+  var n = pound || 1
+  return "Total price for " + fruit + " is $" + n * 0.32
+})
+
+price("Oranges")      // => "Total price for Oranges is $1"
+price("Apples", 5)    // => "Total price for Apples is $1.6"
+
+// Errors are thrown for unknown cases:
+price("Cherries", 2)  // => TypeError: Method price#0hq76f not implemented for: Cherries
+
+// Although new cases can be defined
+price.define("Cherries", function(fruit, pound) {
+  var n = pound || 1
+  return "Total price for " + fruit + " is $" + n * 3.00
+})
+
+price("Cherries", 2)  // => "Total price for Cherries is $6"
+```
+
+## Install
+
+    npm install variator
+
+[switch]:https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Statements/switch

core.js

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+"use strict";
+
+var method = require("method")
+
+var make = Object.create
+
+var define = method.define
+var implement = method.implement
+
+var cases = "cases@" + module.filename
+var labels = "labels@" + module.filename
+var Default = -1
+
+function extendVariator(variator, label, implementation) {
+  var index = variator[labels].indexOf(label)
+  if (index >= 0)
+    throw TypeError("Method is already implemted for label: " + label)
+  if (implementation) {
+    variator[labels].push(label)
+    variator[cases].push(implementation)
+  } else {
+    variator[cases][Default] = label
+  }
+}
+
+function variator(hint) {
+  var dispatcher = method(hint)
+  var prefixes = []
+  var implementations = []
+  dispatcher[labels] = prefixes
+  dispatcher[cases] = implementations
+  dispatcher.define(function dispatch(label) {
+    var index = prefixes.indexOf(label)
+    var implementation = implementations[index]
+    if (!implementation)
+      throw TypeError("Method " + dispatcher + " not implemented for: " + label)
+    return implementation.apply(dispatcher, arguments)
+  })
+  define.implement(dispatcher, extendVariator)
+  implement.implement(dispatcher, extendVariator)
+
+  return dispatcher
+}
+
+module.exports = variator

package.json

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+{
+  "name": "variator",
+  "id": "variator",
+  "version": "0.0.1",
+  "description": "Prefix based method dispatch",
+  "keywords": [
+    "variator"
+  ],
+  "author": "Irakli Gozalishvili <rfobic@gmail.com> (http://jeditoolkit.com)",
+  "homepage": "https://github.com/Gozala/variator",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/Gozala/variator.git",
+    "web": "https://github.com/Gozala/variator"
+  },
+  "bugs": {
+    "url": "http://github.com/Gozala/variator/issues/"
+  },
+  "devDependencies": {
+    "test": "~0.x.0",
+    "phantomify": "~0.x.0",
+    "repl-utils": "~1.0.0"
+  },
+  "main": "./core.js",
+  "scripts": {
+    "repl": "node node_modules/repl-utils",
+    "test": "npm run test-node && npm run test-browser",
+    "test-browser": "node ./node_modules/phantomify/bin/cmd.js ./test/index.js",
+    "test-node": "node ./test/index.js",
+    "postinstall": "npm dedup"
+  },
+  "licenses": [
+    {
+      "type": "MIT",
+      "url": "https://github.com/Gozala/variator/License.md"
+    }
+  ],
+  "dependencies": {
+    "method": "~1.0.2"
+  }
+}

test/index.js

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+"use strict";
+
+var variator = require("../core")
+
+exports["test not implemented"] = function(assert) {
+  var fn = variator("fn")
+
+  assert.throws(function() {
+    fn(1)
+  }, /not implemented for:/, "method not implemented")
+}
+
+exports["test define"] = function(assert) {
+  var fn = variator("fn")
+  fn.define("foo", function(foo, arg) {
+    return [foo, arg]
+  })
+
+  assert.deepEqual(fn("foo", "bar"), ["foo", "bar"],
+                   "argument was dispatched")
+
+  assert.throws(function() {
+    fn("bar", "foo")
+  }, /not implemented for:/, "method not implemented")
+}
+
+exports["test default"] = function(assert) {
+  var fn = variator("fn")
+  var foo = {}
+  var bar = {}
+
+  fn.define(function() { return false })
+  fn.define(foo, function(foo, arg) { return true })
+
+  assert.equal(fn(bar), false, "dispatches on default")
+  assert.equal(fn(foo), true, "dispatches no implementation")
+}
+
+
+require("test").run(exports)