add postcss adapter

docs/postcss.md

@@ -0,0 +1,33 @@
+# PostCSS
+This is the compiler interface to [PostCSS](https://github.com/postcss/postcss). PostCSS is a tool for transforming CSS with JS plugins. These plugins can support variables and mixins, transpile future CSS syntax, inline images, and more.
+
+## Supported Methods
+ - render
+
+## Source Maps
+
+Source maps are supported by the PostCSS adapter. Just pass in a `map` option [as described in the docs](https://github.com/postcss/postcss#source-map), and it will come back as `sourcemap` on the response object.
+
+## Additional Options
+### [Use](https://github.com/postcss/postcss/blob/master/API.md#processoruseplugin)
+
+ - key: `use`
+ - type: `Array|Function|Object`
+ - default: `[]`
+
+Adds one or more plugins to be used as a CSS processor.
+
+```coffee
+pcss = accord.load('postcss')
+varPlugin = require('postcss-simple-vars')
+
+pcss.render(
+  '$color: green;\n\n.test { background: $color; }'
+  use: [varPlugin]
+).catch(
+  (err) -> console.error err
+).done(
+  (res) -> console.log res.result
+)
+```
+

lib/adapters/postcss.coffee

@@ -0,0 +1,21 @@
+Adapter    = require '../adapter_base'
+W          = require 'when'
+_          = require 'lodash'
+sourcemaps = require '../sourcemaps'
+
+class PostCSS extends Adapter
+  name: 'postcss'
+  extensions: ['css']
+  output: 'css'
+
+  _render: (str, options) ->
+    use = options.use ? []
+    processor = @engine(use)
+
+    options.map = {inline: false} if options.map is true
+
+    W(processor.process(str, options))
+      .then (res) ->
+        { result: res.css, sourcemap: res.map }
+
+module.exports = PostCSS

package.json

@@ -17,7 +17,9 @@
     "lodash": "3.x",
     "resolve": "1.x",
     "uglify-js": "2.x",
-    "when": "3.x"
+    "when": "3.x",
+    "postcss": "~4.1.5",
+    "postcss-simple-vars": "~0.2.4"
   },
   "devDependencies": {
     "acorn": "latest",

readme.md

@@ -104,6 +104,7 @@ It's also important to note that accord returns an object rather than a string f
 - [scss](https://github.com/andrew/node-sass)
 - [less](https://github.com/less/less.js/)
 - [myth](https://github.com/segmentio/myth)
+- [postcss](https://github.com/postcss/postcss)
 
 #### JavaScript
 
@@ -156,6 +157,7 @@ Accord now supports source map generation for any language that also supports so
 - coffeescript
 - minify-js
 - 6to5
+- postcss
 
 Accord returns all source maps as javascript objects, and if available will prefer a [v3 sourcemap](https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit) over any other format. You can find the primary sourcemap on the object returned from accord under the `sourcemap` key. If there are multiple sourcemaps generated, alternate ones will be avaiable under different keys, which you can find on the object returned from accord after a compile.
 

test/fixtures/postcss/basic.css

@@ -0,0 +1,3 @@
+.test2 {
+  color: blue;
+}

test/fixtures/postcss/expected/basic.css

@@ -0,0 +1,3 @@
+.test2 {
+  color: blue;
+}

test/fixtures/postcss/expected/string.css

@@ -0,0 +1 @@
+.test { color: green; }

test/fixtures/postcss/expected/var.css

@@ -0,0 +1,3 @@
+.test {
+  background: green;
+}

test/fixtures/postcss/var.css

@@ -0,0 +1,5 @@
+$color: green;
+
+.test {
+  background: $color;
+}

test/test.coffee

@@ -1162,3 +1162,31 @@ describe 'cjsx', ->
   it 'should not be able to compile', (done) ->
     @cjsx.compile()
       .done(((r) -> should.not.exist(r); done()), ((r) -> should.exist(r); done()))
+
+describe 'postcss', ->
+
+  before ->
+    @postcss = accord.load('postcss')
+    @path = path.join(__dirname, 'fixtures', 'postcss')
+
+  it 'should expose name, extensions, output, and engine', ->
+    @postcss.extensions.should.be.an.instanceOf(Array)
+    @postcss.output.should.be.a('string')
+    @postcss.engine.should.be.ok
+    @postcss.name.should.be.ok
+
+  it 'should render a string', (done) ->
+    @postcss.render('.test { color: green; }')
+      .done((res) => should.match_expected(@postcss, res.result, path.join(@path, 'string.css'), done))
+
+  it 'should render a file', (done) ->
+    lpath = path.join(@path, 'basic.css')
+    @postcss.renderFile(lpath)
+      .done((res) => should.match_expected(@postcss, res.result, lpath, done))
+
+  it 'should render a file with plugin', (done) ->
+    lpath = path.join(@path, 'var.css')
+    varsPlugin = require('postcss-simple-vars')
+    @postcss.renderFile(lpath, {use: [varsPlugin]})
+      .done((res) => should.match_expected(@postcss, res.result, lpath, done))
+