# sass 1.24.1

A Sass implementation in Dart.




## Installing
```
export PUB_HOSTED_URL=https://pub.mirror.p-hatan.ir
flutter pub add 'sass:1.24.1'
```
Published: 2020-01-03T00:51:12.399330Z
Expected archive SHA-256: 6330c0cf2c7e0a949f8b4e4e2ba59b8b27e99a86563ab70fe477129dec7e035a

Available in cache; verification: upstream_checksum
## Direct dependencies
- args: >=1.4.0 <2.0.0
- async: >=1.10.0 <3.0.0
- charcode: ^1.1.0
- cli_repl: >=0.1.3 <0.3.0
- collection: ^1.8.0
- meta: ^1.1.7
- package_resolver: ^1.0.0
- path: ^1.6.0
- source_maps: ^0.10.5
- source_span: ^1.4.0
- stack_trace: >=0.9.0 <2.0.0
- stream_transform: >=0.0.20 <2.0.0
- string_scanner: >=0.1.5 <2.0.0
- term_glyph: ^1.0.0
- tuple: ^1.0.0
- watcher: ^0.9.6

## Package README (untrusted upstream documentation)
A [Dart][dart] implementation of [Sass][sass]. **Sass makes CSS fun again**.

<table>
  <tr>
    <td>
      <img width="118px" alt="Sass logo" src="https://rawgit.com/sass/sass-site/master/source/assets/img/logos/logo.svg" />
    </td>
    <td valign="middle">
      <a href="https://www.npmjs.com/package/sass"><img width="100%" alt="npm statistics" src="https://nodei.co/npm/sass.png?downloads=true"></a>
    </td>
    <td valign="middle">
      <a href="https://pub.dartlang.org/packages/sass"><img alt="Pub version" src="https://img.shields.io/pub/v/sass.svg"></a>
      <br>
      <a href="https://travis-ci.org/sass/dart-sass"><img alt="Travis build status" src="https://api.travis-ci.org/sass/dart-sass.svg?branch=master"></a>
      <br>
      <a href="https://ci.appveyor.com/project/nex3/dart-sass"><img alt="Appveyor build status" src="https://ci.appveyor.com/api/projects/status/84rl9hvu8uoecgef?svg=true"></a>
    </td>
  </tr>
</table>

[dart]: https://www.dartlang.org
[sass]: https://sass-lang.com/

* [Using Dart Sass](#using-dart-sass)
  * [From Chocolatey or Scoop (Windows)](#from-chocolatey-or-scoop-windows)
  * [From Homebrew (OS X)](#from-homebrew-os-x)
  * [Standalone](#standalone)
  * [From npm](#from-npm)
  * [From Pub](#from-pub)
  * [From Source](#from-source)
* [JavaScript API](#javascript-api)
* [Why Dart?](#why-dart)
* [Compatibility Policy](#compatibility-policy)
  * [Browser Compatibility](#browser-compatibility)
  * [Node.js Compatibility](#nodejs-compatibility)
* [Behavioral Differences from Ruby Sass](#behavioral-differences-from-ruby-sass)

## Using Dart Sass

There are a few different ways to install and run Dart Sass, depending on your
environment and your needs.

### From Chocolatey or Scoop (Windows)

If you use [the Chocolatey package manager](https://chocolatey.org/)
or [the Scoop package manager](https://github.com/lukesampson/scoop) for
Windows, you can install Dart Sass by running

```cmd
choco install sass
```

or

```cmd
scoop install sass
```

That'll give you a `sass` executable on your command line that will run Dart
Sass.

### From Homebrew (OS X)

If you use [the Homebrew package manager](https://brew.sh/) for Mac OS X, you
can install Dart Sass by running

```sh
brew install sass/sass/sass
```

That'll give you a `sass` executable on your command line that will run Dart
Sass.

### Standalone

You can download the standalone Dart Sass archive for your operating
system—containing the Dart VM and the snapshot of the executable—from [the
GitHub release page][]. Extract it, [add the directory to your path][], restart
your terminal, and the `sass` executable is ready to run!

[the GitHub release page]: https://github.com/sass/dart-sass/releases/
[add the directory to your path]: https://katiek2.github.io/path-doc/

### From npm

Dart Sass is available, compiled to JavaScript, [as an npm package][npm]. You
can install it globally using `npm install -g sass` which will provide access to
the `sass` executable. You can also add it to your project using
`npm install --save-dev sass`. This provides the executable as well as a
library:

[npm]: https://www.npmjs.com/package/sass

```js
var sass = require('sass');

sass.render({file: scss_filename}, function(err, result) { /* ... */ });

// OR

var result = sass.renderSync({file: scss_filename});
```

[See below](#javascript-api) for details on Dart Sass's JavaScript API.

### From Pub

If you're a Dart user, you can install Dart Sass globally using `pub global
activate sass`, which will provide a `sass` executable. You can also add it to
your pubspec and use it as a library. We strongly recommend importing it with
the prefix `sass`:

```dart
import 'package:sass/sass.dart' as sass;

void main(List<String> args) {
  print(sass.compile(args.first));
}
```

See [the Dart API docs][api] for details.

[api]: https://www.dartdocs.org/documentation/sass/latest/sass/sass-library.html

### From Source

Assuming you've already checked out this repository:

1. [Install Dart](https://www.dartlang.org/install). If you download an archive
   manually rather than using an installer, make sure the SDK's `bin` directory
   is on your `PATH`.

2. In this repository, run `pub get`. This will install Dart Sass's
   dependencies.

3. Run `dart bin/sass.dart path/to/file.scss`.

That's it!

## JavaScript API

When installed via npm, Dart Sass supports a JavaScript API that's fully
compatible with [Node Sass][] (with a few exceptions listed below), with support
for both the `render()` and `renderSync()` functions. See [the Sass
website][js api] for full API documentation!

[Node Sass]: https://github.com/sass/node-sass
[js api]: https://sass-lang.com/documentation/js-api

Note however that by default, **`renderSync()` is more than twice as fast as
`render()`** due to the overhead of asynchronous callbacks. To avoid this
performance hit, `render()` can use the [`fibers`][fibers] package to call
asynchronous importers from the synchronous code path. To enable this, pass the
`Fiber` class to the `fiber` option:

[fibers]: https://www.npmjs.com/package/fibers

```js
var sass = require("sass");
var Fiber = require("fibers");

sass.render({
  file: "input.scss",
  importer: function(url, prev, done) {
    // ...
  },
  fiber: Fiber
}, function(err, result) {
  // ...
});
```

Both `render()` and `renderSync()` support the following options:

* [`data`](https://github.com/sass/node-sass#data)
* [`file`](https://github.com/sass/node-sass#file)
* [`functions`](https://github.com/sass/node-sass#functions--v300---experimental)
* [`importer`](https://github.com/sass/node-sass#importer--v200---experimental)
* [`includePaths`](https://github.com/sass/node-sass#includepaths)
* [`indentType`](https://github.com/sass/node-sass#indenttype)
* [`indentWidth`](https://github.com/sass/node-sass#indentwidth)
* [`indentedSyntax`](https://github.com/sass/node-sass#indentedsyntax)
* [`linefeed`](https://github.com/sass/node-sass#linefeed)
* [`omitSourceMapUrl`](https://github.com/sass/node-sass#omitsourcemapurl)
* [`outFile`](https://github.com/sass/node-sass#outfile)
* [`sourceMapContents`](https://github.com/sass/node-sass#sourcemapcontents)
* [`sourceMapEmbed`](https://github.com/sass/node-sass#sourcemapembed)
* [`sourceMapRoot`](https://github.com/sass/node-sass#sourcemaproot)
* [`sourceMap`](https://github.com/sass/node-sass#sourcemap)
* Only the `"expanded"` and `"compressed"` values of
  [`outputStyle`](https://github.com/sass/node-sass#outputstyle) are supported.

No support is intended for the following options:

* [`precision`](https://github.com/sass/node-sass#precision). Dart Sass defaults
  to a sufficiently high precision for all existing browsers, and making this
  customizable would make the code substantially less efficient.

* [`sourceComments`](https://github.com/sass/node-sass#sourcecomments). Source
  maps are the recommended way of locating the origin of generated selectors.

## Why Dart?

Dart Sass has replaced Ruby Sass as the canonical implementation of the Sass
language. We chose Dart because it presented a number of advantages:

* It's fast. The Dart VM is highly optimized, and getting faster all the time
  (for the latest performance numbers, see [`perf.md`][perf]). It's much faster
  than Ruby, and close to par with C++.

* It's portable. The Dart VM has no external dependencies and can compile
  applications into standalone snapshot files, so we can distribute Dart Sass as
  only three files (the VM, the snapshot, and a wrapper script). Dart can also
  be compiled to JavaScript, which makes it easy to distribute Sass through npm,
  which the majority of our users use already.

* It's easy to write. Dart is a higher-level language than C++, which means it
  doesn't require lots of hassle with memory management and build systems. It's
  also statically typed, which makes it easier to confidently make large
  refactors than with Ruby.

* It's friendlier to contributors. Dart is substantially easier to learn than
  Ruby, and many Sass users in Google in particular are already familiar with
  it. More contributors translates to faster, more consistent development.

[perf]: https://github.com/sass/dart-sass/blob/master/perf.md

## Compatibility Policy

For the most part, Dart Sass follows [semantic versioning][]. We consider all of
the following to be part of the versioned API:

[semantic versioning]: https://semver.org/

* The Sass language semantics implemented by Dart Sass.
* The Dart API.
* The JavaScript API.
* The command-line interface.

Because Dart Sass has a single version that's shared across the Dart,
JavaScript, and standalone distributions, this may mean that we increment the
major version number when there are in fact no breaking changes for one or more
distributions. However, we will attempt to limit the number of breaking changes
we make and group them in as few releases as possible to minimize churn. We
strongly encourage users to use [the changelog][] for a full understanding of
all the changes in each release.

[the changelog]: https://github.com/sass/dart-sass/blob/master/CHANGELOG.md

There is one exception where breaking changes may be made outside of a major
version revision. It is occasionally the case that CSS adds a feature that's
incompatible with existing Sass syntax in some way. Because Sass is committed to
full CSS compatibility, we occasionally need to break compatibility with old
Sass code in order to remain compatible with CSS.

In these cases, we will first release a version of Sass that emits deprecation
warnings for any stylesheets whose behavior will change. Then, at least three
months after the release of a version with these deprecation warnings, we will
release a minor version with the breaking change to the Sass language semantics.

### Browser Compatibility

In general, we consider any change to Dart Sass's CSS output that would cause
that CSS to stop working in a real browser to be a breaking change. However,
there are some cases where such a change would have substantial benefits and
would only negatively affect a small minority of rarely-used browsers. We don't
want to have to block such a change on a major version release.

As such, if a change would break compatibility with less than 2% of the global
market share of browser according to [StatCounter GlobalStats][], we may release
a minor version of Dart Sass with that change.

[StatCounter GlobalStats]: http://gs.statcounter.com/

### Node.js Compatibility

We consider dropping support for a given version of Node.js to be a breaking
change *as long as* that version is still supported by Node.js. This means that
releases listed as Current, Active LTS, or Maintenance LTS according to [the
Node.js release page][]. Once a Node.js version is out of LTS, Dart Sass
considers itself free to break support if necessary.

[the Node.js release page]: https://nodejs.org/en/about/releases/

## Behavioral Differences from Ruby Sass

There are a few intentional behavioral differences between Dart Sass and Ruby
Sass. These are generally places where Ruby Sass has an undesired behavior, and
it's substantially easier to implement the correct behavior than it would be to
implement compatible behavior. These should all have tracking bugs against Ruby
Sass to update the reference behavior.

1. `@extend` only accepts simple selectors, as does the second argument of
   `selector-extend()`. See [issue 1599][].

2. Subject selectors are not supported. See [issue 1126][].

3. Pseudo selector arguments are parsed as `<declaration-value>`s rather than
   having a more limited custom parsing. See [issue 2120][].

4. The numeric precision is set to 10. See [issue 1122][].

5. The indented syntax parser is more flexible: it doesn't require consistent
   indentation across the whole document. See [issue 2176][].

6. Colors do not support channel-by-channel arithmetic. See [issue 2144][].

7. Unitless numbers aren't `==` to unit numbers with the same value. In
   addition, map keys follow the same logic as `==`-equality. See
   [issue 1496][].

8. `rgba()` and `hsla()` alpha values with percentage units are interpreted as
   percentages. Other units are forbidden. See [issue 1525][].

9. Too many variable arguments passed to a function is an error. See
   [issue 1408][].

10. Allow `@extend` to reach outside a media query if there's an identical
    `@extend` defined outside that query. This isn't tracked explicitly, because
    it'll be irrelevant when [issue 1050][] is fixed.

11. Some selector pseudos containing placeholder selectors will be compiled
    where they wouldn't be in Ruby Sass. This better matches the semantics of
    the selectors in question, and is more efficient. See [issue 2228][].

12. The old-style `:property value` syntax is not supported in the indented
    syntax. See [issue 2245][].

13. The reference combinator is not supported. See [issue 303][].

14. Universal selector unification is symmetrical. See [issue 2247][].

15. `@extend` doesn't produce an error if it matches but fails to unify. See
    [issue 2250][].

16. Dart Sass currently only supports UTF-8 documents. We'd like to support
    more, but Dart currently doesn't support them. See [dart-lang/sdk#11744][],
    for example.

[issue 1599]: https://github.com/sass/sass/issues/1599
[issue 1126]: https://github.com/sass/sass/issues/1126
[issue 2120]: https://github.com/sass/sass/issues/2120
[issue 1122]: https://github.com/sass/sass/issues/1122
[issue 2176]: https://github.com/sass/sass/issues/2176
[issue 2144]: https://github.com/sass/sass/issues/2144
[issue 1496]: https://github.com/sass/sass/issues/1496
[issue 1525]: https://github.com/sass/sass/issues/1525
[issue 1408]: https://github.com/sass/sass/issues/1408
[issue 1050]: https://github.com/sass/sass/issues/1050
[issue 2228]: https://github.com/sass/sass/issues/2228
[issue 2245]: https://github.com/sass/sass/issues/2245
[issue 303]: https://github.com/sass/sass/issues/303
[issue 2247]: https://github.com/sass/sass/issues/2247
[issue 2250]: https://github.com/sass/sass/issues/2250
[dart-lang/sdk#11744]: https://github.com/dart-lang/sdk/issues/11744

Disclaimer: this is not an official Google product.

## Changelog
## 1.24.1

* Fix a bug where the wrong file could be loaded when the same URL is used by
  both a `@use` rule and an `@import` rule.

## 1.24.0

* Add an optional `with` clause to the `@forward` rule. This works like the
  `@use` rule's `with` clause, except that `@forward ... with` can declare
  variables as `!default` to allow downstream modules to reconfigure their
  values.

* Support configuring modules through `@import` rules.

## 1.23.8

* **Potentially breaking bug fix:** Members loaded through a nested `@import`
  are no longer ever accessible outside that nested context.

* Don't throw an error when importing two modules that both forward members with
  the same name. The latter name now takes precedence over the former, as per
  the specification.

### Dart API

* `SassFormatException` now implements `SourceSpanFormatException` (and thus
  `FormatException`).

## 1.23.7

* No user-visible changes

## 1.23.6

* No user-visible changes.

## 1.23.5

* Support inline comments in the indented syntax.

* When an overloaded function receives the wrong number of arguments, guess
  which overload the user actually meant to invoke, and display the invalid
  argument error for that overload.

* When `@error` is used in a function or mixin, print the call site rather than
  the location of the `@error` itself to better match the behavior of calling a
  built-in function that throws an error.

## 1.23.4

### Command-Line Interface

* Fix a bug where `--watch` wouldn't watch files referred to by `@forward`
  rules.

## 1.23.3

* Fix a bug where selectors were being trimmed over-eagerly when `@extend`
  crossed module boundaries.

## 1.23.2

### Command-Line Interface

* Fix a bug when compiling all Sass files in a directory where a CSS file could
  be compiled to its own location, creating an infinite loop in `--watch` mode.

* Properly compile CSS entrypoints in directories outside of `--watch` mode.

## 1.23.1

* Fix a bug preventing built-in modules from being loaded within a configured
  module.

* Fix a bug preventing an unconfigured module from being loaded from within two
  different configured modules.

* Fix a bug when `meta.load-css()` was used to load some files that included
  media queries.

* Allow `saturate()` in plain CSS files, since it can be used as a plain CSS
  filter function.

* Improve the error messages for trying to access functions like `lighten()`
  from the `sass:color` module.

## 1.23.0

* **Launch the new Sass module system!** This adds:

  * The [`@use` rule][], which loads Sass files as *modules* and makes their
    members available only in the current file, with automatic namespacing.

    [`@use` rule]: https://sass-lang.com/documentation/at-rules/use

  * The [`@forward` rule][], which makes members of another Sass file available
    to stylesheets that `@use` the current file.

    [`@forward` rule]: https://sass-lang.com/documentation/at-rules/forward

  * Built-in modules named `sass:color`, `sass:list`, `sass:map`, `sass:math`,
    `sass:meta`, `sass:selector`, and `sass:string` that provide access to all
    the built-in Sass functions you know and love, with automatic module
    namespaces.

  * The [`meta.load-css()` mixin][], which includes the CSS contents of a module
    loaded from a (potentially dynamic) URL.

    [`meta.load-css()` mixin]: https://sass-lang.com/documentation/modules/meta#load-css

  * The [`meta.module-variables()` function][], which provides access to the
    variables defined in a given module.

    [`meta.module-variables()` function]: https://sass-lang.com/documentation/modules/meta#module-variables

  * The [`meta.module-functions()` function][], which provides access to the
    functions defined in a given module.

    [`meta.module-functions()` function]: https://sass-lang.com/documentation/modules/meta#module-functions

  Check out [the Sass blog][migrator blog] for more information on the new
  module system. You can also use the new [Sass migrator][] to automatically
  migrate your stylesheets to the new module system!

  [migrator blog]: http://sass-lang.com/blog/posts/7858341-the-module-system-is-launched
  [Sass migrator]: https://sass-lang.com/documentation/cli/migrator

## 1.22.12

* **Potentially breaking bug fix:** character sequences consisting of two or
  more hyphens followed by a number (such as `--123`), or two or more hyphens on
  their own (such as `--`), are now parsed as identifiers [in accordance with
  the CSS spec][ident-token-diagram].

  [ident-token-diagram]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram

  The sequence `--` was previously parsed as multiple applications of the `-`
  operator. Since this is unlikely to be used intentionally in practice, we
  consider this bug fix safe.

### Command-Line Interface

* Fix a bug where changes in `.css` files would be ignored in `--watch` mode.

### JavaScript API

* Allow underscore-separated custom functions to be defined.

* Improve the performance of Node.js compilation involving many `@import`s.

## 1.22.11

* Don't try to load unquoted plain-CSS indented-syntax imports.

* Fix a couple edge cases in `@extend` logic and related selector functions:

  * Recognize `:matches()` and similar pseudo-selectors as superselectors of
    matching complex selectors.

  * Recognize `::slotted()` as a superselector of other `::slotted()` selectors.

  * Regonize `:current()` with a vendor prefix as a superselector.

## 1.22.10

* Fix a bug in which `get-function()` would fail to find a dash-separated
  function when passed a function name with underscores.

## 1.22.9

* Include argument names when reporting range errors and selector parse errors.

* Avoid double `Error:` headers when reporting selector parse errors.

* Clarify the error message when the wrong number of positional arguments are
  passed along with a named argument.

### JavaScript API

* Re-add support for Node Carbon (8.x).

## 1.22.8

### JavaScript API

* Don't crash when running in a directory whose name contains URL-sensitive
  characters.

* Drop support for Node Carbon (8.x), which doesn't support `url.pathToFileURL`.

## 1.22.7

* Restrict the supported versions of the Dart SDK to `^2.4.0`.

## 1.22.6

* **Potentially breaking bug fix:** The `keywords()` function now converts
  underscore-separated argument names to hyphen-separated names. This matches
  LibSass's behavior, but not Ruby Sass's.

* Further improve performance for logic-heavy stylesheets.

* Improve a few error messages.

## 1.22.5

### JavaScript API

* Improve performance for logic-heavy stylesheets.

## 1.22.4

* Fix a bug where at-rules imported from within a style rule would appear within
  that style rule rather than at the root of the document.

## 1.22.3

* **Potentially breaking bug fix:** The argument name for the `saturate()`
  function is now `$amount`, to match the name in LibSass and originally in Ruby
  Sass.

* **Potentially breaking bug fix:** The `invert()` function now properly returns
  `#808080` when passed `$weight: 50%`. This matches the behavior in LibSass and
  originally in Ruby Sass, as well as being consistent with other nearby values
  of `$weight`.

* **Potentially breaking bug fix:** The `invert()` function now throws an error
  if it's used [as a plain CSS function][plain-CSS invert] *and* the Sass-only
  `$weight` parameter is passed. This never did anything useful, so it's
  considered a bug fix rather than a full breaking change.

  [plain-CSS invert]: https://developer.mozilla.org/en-US/docs/Web/CSS/filter-function/invert

* **Potentially breaking bug fix**: The `str-insert()` function now properly
  inserts at the end of the string if the `$index` is `-1`. This matches the
  behavior in LibSass and originally in Ruby Sass.

* **Potentially breaking bug fix**: An empty map returned by `map-remove()` is
  now treated as identical to the literal value `()`, rather than being treated
  as though it had a comma separator. This matches the original behavior in Ruby
  Sass.

* The `adjust-color()` function no longer throws an error when a large `$alpha`
  value is combined with HSL adjustments.

* The `alpha()` function now produces clearer error messages when the wrong
  number of arguments are passed.

* Fix a bug where the `str-slice()` function could produce invalid output when
  passed a string that contains characters that aren't represented as a single
  byte in UTF-16.

* Improve the error message for an unknown separator name passed to the `join()`
  or `append()` functions.

* The `zip()` function no longer deadlocks if passed no arguments.

* The `map-remove()` function can now take a `$key` named argument. This matches
  the signature in LibSass and originally in Ruby Sass.

## 1.22.2

### JavaScript API

* Avoid re-assigning the `require()` function to make the code statically
  analyzable by Webpack.

## 1.22.1

### JavaScript API

* Expand the dependency on `chokidar` to allow 3.x.

## 1.22.0

* Produce better stack traces when importing a file that contains a syntax
  error.

* Make deprecation warnings for `!global` variable declarations that create new
  variables clearer, especially in the case where the `!global` flag is
  unnecessary because the variables are at the top level of the stylesheet.

### Dart API

* Add a `Value.realNull` getter, which returns Dart's `null` if the value is
  Sass's null.

## 1.21.0

### Dart API

* Add a `sass` executable when installing the package through `pub`.

* Add a top-level `warn()` function for custom functions and importers to print
  warning messages.

## 1.20.3

* No user-visible changes.

## 1.20.2

* Fix a bug where numbers could be written using exponential notation in
  Node.js.

* Fix a crash that would appear when writing some very large integers to CSS.

### Command-Line Interface

* Improve performance for stand-alone packages on Linux and Mac OS.

### JavaScript API

* Pass imports to custom importers before resolving them using `includePaths` or
  the `SASS_PATH` environment variable. This matches Node Sass's behavior, so
  it's considered a bug fix.

## 1.20.1

* No user-visible changes.

## 1.20.0

* Support attribute selector modifiers, such as the `i` in `[title="test" i]`.

### Command-Line Interface

* When compilation fails, Sass will now write the error message to the CSS
  output as a comment and as the `content` property of a `body::before` rule so
  it will show up in the browser (unless compiling to standard output). This can
  be disabled with the `--no-error-css` flag, or forced even when compiling to
  standard output with the `--error-css` flag.

### Dart API

* Added `SassException.toCssString()`, which returns the contents of a CSS
  stylesheet describing the error, as above.

## 1.19.0

* Allow `!` in `url()`s without quotes.

### Dart API

* `FilesystemImporter` now doesn't change its effective directory if the working
  directory changes, even if it's passed a relative argument.

## 1.18.0

* Avoid recursively listing directories when finding the canonical name of a
  file on case-insensitive filesystems.

* Fix importing files relative to `package:`-imported files.

* Don't claim that "package:" URLs aren't supported when they actually are.

### Command-Line Interface

* Add a `--no-charset` flag. If this flag is set, Sass will never emit a
  `@charset` declaration or a byte-order mark, even if the CSS file contains
  non-ASCII characters.

### Dart API

* Add a `charset` option to `compile()`, `compileString()`, `compileAsync()` and
  `compileStringAsync()`. If this option is set to `false`, Sass will never emit
  a `@charset` declaration or a byte-order mark, even if the CSS file contains
  non-ASCII characters.

* Explicitly require that importers' `canonicalize()` methods be able to take
  paths relative to their outputs as valid inputs. This isn't considered a
  breaking change because the importer infrastructure already required this in
  practice.

## 1.17.4

* Consistently parse U+000C FORM FEED, U+000D CARRIAGE RETURN, and sequences of
  U+000D CARRIAGE RETURN followed by U+000A LINE FEED as individual newlines.

### JavaScript API

* Add a `sass.types.Error` constructor as an alias for `Error`. This makes our
  custom function API compatible with Node Sass's.

## 1.17.3

* Fix an edge case where slash-separated numbers were written to the stylesheet
  with a slash even when they're used as part of another arithmetic operation,
  such as being concatenated with a string.

* Don't put style rules inside empty `@keyframes` selectors.

## 1.17.2

* Deprecate `!global` variable assignments to variables that aren't yet defined.
  This deprecation message can be avoided by assigning variables to `null` at
  the top level before globally assigning values to them.

### Dart API

* Explicitly mark classes that were never intended to be subclassed or
  implemented as "sealed".

## 1.17.1

* Properly quote attribute selector values that start with identifiers but end
  with a non-identifier character.

## 1.17.0

* Improve error output, particularly for errors that cover multiple lines.

* Improve source locations for some parse errors. Rather than pointing to the
  next token that wasn't what was expected, they point *after* the previous
  token. This should generally provide more context for the syntax error.

* Produce a better error message for style rules that are missing the closing
  `}`.

* Produce a better error message for style rules and property declarations
  within `@function` rules.

### Command-Line Interface

* Passing a directory on the command line now compiles all Sass source files in
  the directory to CSS files in the same directory, as though `dir:dir` were
  passed instead of just `dir`.

* The new error output uses non-ASCII Unicode characters by default. Add a
  `--no-unicode` flag to disable this.

## 1.16.1

* Fix a performance bug where stylesheet evaluation could take a very long time
  when many binary operators were used in sequence.

## 1.16.0

* `rgb()` and `hsl()` now treat unquoted strings beginning with `env()`,
  `min()`, and `max()` as special number strings like `calc()`.

## 1.15.3

* Properly merge `all and` media queries. These queries were previously being
  merged as though `all` referred to a specific media type, rather than all
  media types.

* Never remove units from 0 values in compressed mode. This wasn't safe in
  general, since some properties (such as `line-height`) interpret `0` as a
  `<number>` rather than a `<length>` which can break CSS transforms. It's
  better to do this optimization in a dedicated compressor that's aware of CSS
  property semantics.

* Match Ruby Sass's behavior in some edge-cases involving numbers with many
  significant digits.

* Emit escaped tab characters in identifiers as `\9` rather than a backslash
  followed by a literal tab.

### Command-Line Interface

* The source map generated for a stylesheet read from standard input now uses a
  `data:` URL to include that stylesheet's contents in the source map.

### Node JS API

* `this.includePaths` for a running importer is now a `;`-separated string on
  Windows, rather than `:`-separated. This matches Node Sass's behavior.

### Dart API

* The URL used in a source map to refer to a stylesheet loaded from an importer
  is now `ImportResult.sourceMapUrl` as documented.

## 1.15.2

### Node JS API

* When `setValue()` is called on a Sass string object, make it unquoted even if
  it was quoted originally, to match the behavior of Node Sass.

## 1.15.1

* Always add quotes to attribute selector values that begin with `--`, since IE
  11 doesn't consider them to be identifiers.

## 1.15.0

* Add support for passing arguments to `@content` blocks. See [the
  proposal][content-args] for details.

* Add support for the new `rgb()` and `hsl()` syntax introduced in CSS Colors
  Level 4, such as `rgb(0% 100% 0% / 0.5)`. See [the proposal][color-4-rgb-hsl]
  for more details.

* Add support for interpolation in at-rule names. See [the
  proposal][at-rule-interpolation] for details.

* Add paths from the `SASS_PATH` environment variable to the load paths in the
  command-line interface, Dart API, and JS API. These load paths are checked
  just after the load paths explicitly passed by the user.

* Allow saturation and lightness values outside of the `0%` to `100%` range in
  the `hsl()` and `hsla()` functions. They're now clamped to be within that
  range rather than producing an error if they're outside it.

* Properly compile selectors that end in escaped whitespace.

[content-args]: https://github.com/sass/language/blob/master/accepted/content-args.md
[color-4-rgb-hsl]: https://github.com/sass/language/blob/master/accepted/color-4-rgb-hsl.md
[at-rule-interpolation]: https://github.com/sass/language/blob/master/accepted/at-rule-interpolation.md

### JavaScript API

* Always include the error location in error messages.

## 1.14.4

* Properly escape U+0009 CHARACTER TABULATION in unquoted strings.

## 1.14.3

* Treat `:before`, `:after`, `:first-line`, and `:first-letter` as
  pseudo-elements for the purposes of `@extend`.

* When running in compressed mode, remove spaces around combinators in complex
  selectors, so a selector like `a > b` is output as `a>b`.

* Properly indicate the source span for errors involving binary operation
  expressions whose operands are parenthesized.

## 1.14.2

* Fix a bug where loading the same stylesheet from two different import paths
  could cause its imports to fail to resolve.

* Properly escape U+001F INFORMATION SEPARATOR ONE in unquoted strings.

### Command-Line Interface

* Don't crash when using `@debug` in a stylesheet passed on standard input.

### Dart API

* `AsyncImporter.canonicalize()` and `Importer.canonicalize()` must now return
  absolute URLs. Relative URLs are still supported, but are deprecated and will
  be removed in a future release.

## 1.14.1

* Canonicalize escaped digits at the beginning of identifiers as hex escapes.

* Properly parse property declarations that are both *in* content blocks and
  written *after* content blocks.

### Command-Line Interface

* Print more readable paths in `--watch` mode.

## 1.14.0

### BREAKING CHANGE

In accordance with our [compatibility policy][], breaking changes made for CSS
compatibility reasons are released as minor version revision after a three-month
deprecation period.

[compatibility policy]: README.md#compatibility-policy

* Tokens such as `#abcd` that are now interpreted as hex colors with alpha
  channels, rather than unquoted ID strings.

## 1.13.4

### Node JS

* Tweak JS compilation options to substantially improve performance.

## 1.13.3

* Properly generate source maps for stylesheets that emit `@charset`
  declarations.

### Command-Line Interface

* Don't error out when passing `--embed-source-maps` along with
  `--embed-sources` for stylesheets that contain non-ASCII characters.

## 1.13.2

* Properly parse `:nth-child()` and `:nth-last-child()` selectors with
  whitespace around the argument.

* Don't emit extra whitespace in the arguments for `:nth-child()` and
  `:nth-last-child()` selectors.

* Fix support for CSS hacks in plain CSS mode.

## 1.13.1

* Allow an IE-style single equals operator in plain CSS imports.

## 1.13.0

* Allow `@extend` to be used with multiple comma-separated simple selectors.
  This is already supported by other implementations, but fell through the
  cracks for Dart Sass until now.

* Don't crash when a media rule contains another media rule followed by a style
  rule.

## 1.12.0

### Dart API

* Add a `SassException` type that provides information about Sass compilation
  failures.

### Node JS API

* Remove the source map comment from the compiled JS. We don't ship with the
  source map, so this pointed to nothing.

## 1.11.0

* Add support for importing plain CSS files. They can only be imported *without*
  an extension—for example, `@import "style"` will import `style.css`. Plain CSS
  files imported this way only support standard CSS features, not Sass
  extensions.

  See [the proposal][css-import] for details.

* Add support for CSS's `min()` and `max()` [math functions][]. A `min()` and
  `max()` call will continue to be parsed as a Sass function if it involves any
  Sass-specific features like variables or function calls, but if it's valid
  plain CSS (optionally with interpolation) it will be emitted as plain CSS instead.

  See [the proposal][css-min-max] for details.

* Add support for range-format media features like `(10px < width < 100px)`. See
  [the proposal][media-ranges] for details.

* Normalize escape codes in identifiers so that, for example, `éclair` and
  `\E9clair` are parsed to the same value. See
  [the proposal][identifier-escapes] for details.

* Don't choke on a [byte-order mark][] at the beginning of a document when
  running in JavaScript.

[math functions]: https://drafts.csswg.org/css-values/#math-function
[css-import]: https://github.com/sass/language/blob/master/accepted/css-imports.md
[css-min-max]: https://github.com/sass/language/blob/master/accepted/min-max.md
[media-ranges]: https://github.com/sass/language/blob/master/accepted/media-ranges.md
[identifier-escapes]: https://github.com/sass/language/blob/master/accepted/identifier-escapes.md
[byte-order mark]: https://en.wikipedia.org/wiki/Byte_order_mark

### Command-Line Interface

* The `--watch` command now continues to recompile a file after a syntax error
  has been detected.

### Dart API

* Added a `Syntax` enum to indicate syntaxes for Sass source files.

* The `compile()` and `compileAsync()` functions now parse files with the `.css`
  extension as plain CSS.

* Added a `syntax` parameter to `compileString()` and `compileStringAsync()`.

* Deprecated the `indented` parameter to `compileString()` and `compileStringAsync()`.

* Added a `syntax` parameter to `new ImporterResult()` and a
  `ImporterResult.syntax` getter to set the syntax of the source file.

* Deprecated the `indented` parameter to `new ImporterResult()` and the
  `ImporterResult.indented` getter in favor of `syntax`.

## 1.10.4

### Command-Line Interface

* Fix a Homebrew installation failure.

## 1.10.3

### Command-Line Interface

* Run the Chocolatey script with the correct arguments so it doesn't crash.

## 1.10.2

* No user-visible changes.

## 1.10.1

### Node JS API

* Don't crash when passing both `includePaths` and `importer`.

## 1.10.0

* When two `@media` rules' queries can't be merged, leave nested rules in place
  for browsers that support them.

* Fix a typo in an error message.

## 1.9.2

### Node JS API

* Produce more readable filesystem errors, such as when a file doesn't exist.

## 1.9.1

### Command-Line Interface

* Don't emit ANSI codes to Windows terminals that don't support them.

* Fix a bug where `--watch` crashed on Mac OS.

## 1.9.0

### Node API

* Add support for `new sass.types.Color(argb)` for creating colors from ARGB hex
  numbers. This was overlooked when initially adding support for Node Sass's
  JavaScript API.

## 1.8.0

### Command-Line Interface

* Add a `--poll` flag to make `--watch` mode repeatedly check the filesystem for
  updates rather than relying on native filesystem notifications.

* Add a `--stop-on-error` flag to stop compiling additional files once an error
  is encountered.

## 1.7.3

* No user-visible changes.

## 1.7.2

* Add a deprecation warning for `@-moz-document`, except for cases where only an
  empty `url-prefix()` is used. Support is [being removed from Firefox][] and
  will eventually be removed from Sass as well.

[being removed from Firefox]: https://www.fxsitecompat.com/en-CA/docs/2018/moz-document-support-has-been-dropped-except-for-empty-url-prefix/

* Fix a bug where `@-moz-document` functions with string arguments weren't being
  parsed.

### Command-Line Interface

* Don't crash when a syntax error is added to a watched file.

## 1.7.1

* Fix crashes in released binaries.

## 1.7.0

* Emit deprecation warnings for tokens such as `#abcd` that are ambiguous
  between ID strings and hex colors with alpha channels. These will be
  interpreted as colors in a release on or after 19 September 2018.

* Parse unambiguous hex colors with alpha channels as colors.

* Fix a bug where relative imports from files on the load path could look in the
  incorrect location.

## 1.6.2

### Command-Line Interface

* Fix a bug where the source map comment in the generated CSS could refer to the
  source map file using an incorrect URL.

## 1.6.1

* No user-visible changes.

## 1.6.0

* Produce better errors when expected tokens are missing before a closing brace.

* Avoid crashing when compiling a non-partial stylesheet that exists on the
  filesystem next to a partial with the same name.

### Command-Line Interface

* Add support for the `--watch`, which watches for changes in Sass files on the
  filesystem and ensures that the compiled CSS is up-to-date.

* When using `--update`, surface errors when an import doesn't exist even if the
  file containing the import hasn't been modified.

* When compilation fails, delete the output file rather than leaving an outdated
  version.

## 1.5.1

* Fix a bug where an absolute Windows path would be considered an `input:output`
  pair.

* Forbid custom properties that have no values, like `--foo:;`, since they're
  forbidden by the CSS spec.

## 1.5.0

* Fix a bug where an importer would be passed an incorrectly-resolved URL when
  handling a relative import.

* Throw an error when an import is ambiguous due to a partial and a non-partial
  with the same name, or multiple files with different extensions. This matches
  the standard Sass behavior.

### Command-Line Interface

* Add an `--interactive` flag that supports interactively running Sass
  expressions (thanks to [Jen Thakar][]!).

[Jen Thakar]: https://github.com/jathak

## 1.4.0

* Improve the error message for invalid semicolons in the indented syntax.

* Properly disallow semicolons after declarations in the indented syntax.

### Command-Line Interface

* Add support for compiling multiple files at once by writing
  `sass input.scss:output.css`. Note that unlike Ruby Sass, this *always*
  compiles files by default regardless of when they were modified.

  This syntax also supports compiling entire directories at once. For example,
  `sass templates/stylesheets:public/css` compiles all non-partial Sass files
  in `templates/stylesheets` to CSS files in `public/css`.

* Add an `--update` flag that tells Sass to compile only stylesheets that have
  been (transitively) modified since the CSS file was generated.

### Dart API

* Add `Importer.modificationTime()` and `AsyncImporter.modificationTime()` which
  report the last time a stylesheet was modified.

### Node API

* Generate source maps when the `sourceMaps` option is set to a string and the
  `outFile` option is not set.

## 1.3.2

* Add support for `@elseif` as an alias of `@else if`. This is not an
  intentional feature, so using it will cause a deprecation warning. It will be
  removed at some point in the future.

## 1.3.1

### Node API

* Fix loading imports relative to stylesheets that were themselves imported
  though relative include paths.

## 1.3.0

### Command-Line Interface

* Generate source map files by default when writing to disk. This can be
  disabled by passing `--no-source-map`.

* Add a `--source-map-urls` option to control whether the source file URLs in
  the generated source map are relative or absolute.

* Add an `--embed-sources` option to embed the contents of all source files in
  the generated source map.

* Add an `--embed-source-map` option to embed the generated source map as a
  `data:` URL in the generated CSS.

### Dart API

* Add a `sourceMap` parameter to `compile()`, `compileString()`,
  `compileAsync()`, and `compileStringAsync()`. This takes a callback that's
  called with a [`SingleMapping`][] that contains the source map information for
  the compiled CSS file.

[`SingleMapping`]: https://www.dartdocs.org/documentation/source_maps/latest/source_maps.parser/SingleMapping-class.html

### Node API

* Added support for the `sourceMap`, `omitSourceMapUrl`, `outFile`,
  `sourceMapContents`, `sourceMapEmbed`, and `sourceMapRoot` options to
  `render()` and `renderSync()`.

* Fix a bug where passing a relative path to `render()` or `renderSync()` would
  cause relative imports to break.

* Fix a crash when printing warnings in stylesheets compiled using `render()` or
  `renderSync()`.

* Fix a bug where format errors were reported badly on Windows.

## 1.2.1

* Always emit units in compressed mode for `0` dimensions other than lengths and
  angles.

## 1.2.0

* The command-line executable will now create the directory for the resulting
  CSS if that directory doesn't exist.

* Properly parse `#{$var} -#{$var}` as two separate values in a list rather than
  one value being subtracted from another.

* Improve the error message for extending compound selectors.

## 1.1.1

* Add a commit that was accidentally left out of 1.1.0.

## 1.1.0

* The command-line executable can now be used to write an output file to disk
  using `sass input.scss output.css`.

* Use a POSIX-shell-compatible means of finding the location of the `sass` shell
  script.

## 1.0.0

**Initial stable release.**

### Changes Since 1.0.0-rc.1

* Allow `!` in custom property values ([#260][]).

[#260]: https://github.com/sass/dart-sass/issues/260

#### Dart API

* Remove the deprecated `render()` function.

#### Node API

* Errors are now subtypes of the `Error` type.

* Allow both the `data` and `file` options to be passed to `render()` and
  `renderSync()` at once. The `data` option will be used as the contents of the
  stylesheet, and the `file` option will be used as the path for error reporting
  and relative imports. This matches Node Sass's behavior.

## 1.0.0-rc.1

* Add support for importing an `_index.scss` or `_index.sass` file when
  importing a directory.

* Add a `--load-path` command-line option (alias `-I`) for passing additional
  paths to search for Sass files to import.

* Add a `--quiet` command-line option (alias `-q`) for silencing warnings.

* Add an `--indented` command-line option for using the indented syntax with a
  stylesheet from standard input.

* Don't merge the media queries `not type` and `(feature)`. We had previously
  been generating `not type and (feature)`, but that's not actually the
  intersection of the two queries.

* Don't crash on `$x % 0`.

* The standalone executable distributed on GitHub is now named `sass` rather
  than `dart-sass`. The `dart-sass` executable will remain, with a deprecation
  message, until 1.0.0 is released.

### Dart API

* Add a `Logger` class that allows users to control how messages are printed by
  stylesheets.

* Add a `logger` parameter to `compile()`, `compileAsync()`, `compileString()`,
  and `compileStringAsync()`.

### Node JS API

* Import URLs passed to importers are no longer normalized. For example, if a
  stylesheet contains `@import "./foo.scss"`, importers will now receive
  `"./foo.scss"` rather than `"foo.scss"`.

## 1.0.0-beta.5.3

* Support hard tabs in the indented syntax.

* Improve the formatting of comments that don't start on the same line as the
  opening `/*`.

* Preserve whitespace after `and` in media queries in compressed mode.

### Indented Syntax

* Properly parse multi-line selectors.

* Don't deadlock on `/*` comments.

* Don't add an extra `*/` to comments that already have it.

* Preserve empty lines in `/*` comments.

## 1.0.0-beta.5.2

* Fix a bug where some colors would crash `compressed` mode.

## 1.0.0-beta.5.1

* Add a `compressed` output style.

* Emit a warning when `&&` is used, since it's probably not what the user means.

* `round()` now returns the correct results for negative numbers that should
  round down.

* `var()` may now be passed in place of multiple arguments to `rgb()`, `rgba()`,
  `hsl()` and `hsla()`.

* Fix some cases where equivalent numbers wouldn't count as the same keys in
  maps.

* Fix a bug where multiplication like `(1/1px) * (1px/1)` wouldn't properly
  cancel out units.

* Fix a bug where dividing by a compatible unit would produce an invalid
  result.

* Remove a non-`sh`-compatible idiom from the standalone shell script.

### Dart API

* Add a `functions` parameter to `compile()`, `compleString()`,
  `compileAsync()`, and `compileStringAsync()`. This allows users to define
  custom functions in Dart that can be invoked from Sass stylesheets.

* Expose the `Callable` and `AsyncCallable` types, which represent functions
  that can be invoked from Sass.

* Expose the `Value` type and its subclasses, as well as the top-level
  `sassTrue`, `sassFalse`, and `sassNull` values, which represent Sass values
  that may be passed into or returned from custom functions.

* Expose the `OutputStyle` enum, and add a `style` parameter to `compile()`,
  `compleString()`, `compileAsync()`, and `compileStringAsync()` that allows
  users to control the output style.

### Node JS API

* Support the `functions` option.

* Support the `"compressed"` value for the `outputStyle` option.

## 1.0.0-beta.4

* Support unquoted imports in the indented syntax.

* Fix a crash when `:not(...)` extends a selector that appears in
  `:not(:not(...))`.

### Node JS API

* Add support for asynchronous importers to `render()` and `renderSync()`.

### Dart API

* Add `compileAsync()` and `compileStringAsync()` methods. These run
  asynchronously, which allows them to take asynchronous importers (see below).

* Add an `AsyncImporter` class. This allows imports to be resolved
  asynchronously in case no synchronous APIs are available. `AsyncImporter`s are
  only compatible with `compileAysnc()` and `compileStringAsync()`.

## 1.0.0-beta.3

* Properly parse numbers with exponents.

* Don't crash when evaluating CSS variables whose names are entirely
  interpolated (for example, `#{--foo}: ...`).

### Node JS API

* Add support for the `importer` option to `render()` and `renderSync()`.
  Only synchronous importers are currently supported.

### Dart API

* Added an `Importer` class. This can be extended by users to provide support
  for custom resolution for `@import` rules.

* Added built-in `FilesystemImporter` and `PackageImporter` implementations that
  support resolving `file:` and `package:` URLs, respectively.

* Added an `importers` argument to the `compile()` and `compileString()`
  functions that provides `Importer`s to use when resolving `@import` rules.

* Added a `loadPaths` argument to the `compile()` and `compileString()`
  functions that provides paths to search for stylesheets when resolving
  `@import` rules. This is a shorthand for passing `FilesystemImporter`s to the
  `importers` argument.

## 1.0.0-beta.2

* Add support for the `::slotted()` pseudo-element.

* Generated transparent colors will now be emitted as `rgba(0, 0, 0, 0)` rather
  than `transparent`. This works around a bug wherein IE incorrectly handles the
  latter format.

### Command-Line Interface

* Improve the logic for whether to use terminal colors by default.

### Node JS API

* Add support for `data`, `includePaths`, `indentedSyntax`, `lineFeed`,
  `indentWidth`, and `indentType` options to `render()` and `renderSync()`.

* The result object returned by `render()` and `renderSync()` now includes the
  `stats` object which provides metadata about the compilation process.

* The error object thrown by `render()` and `renderSync()` now includes `line`,
  `column`, `file`, `status`, and `formatted` fields. The `message` field and
  `toString()` also provide more information.

### Dart API

* Add a `renderString()` method for rendering Sass source that's not in a file
  on disk.

## 1.0.0-beta.1

* Drop support for the reference combinator. This has been removed from the
  spec, and will be deprecated and eventually removed in other implementations.

* Trust type annotations when compiling to JavaScript, which makes it
  substantially faster.

* Compile to minified JavaScript, which decreases the code size substantially
  and makes startup a little faster.

* Fix a crash when inspecting a string expression that ended in "\a".

* Fix a bug where declarations and `@extend` were allowed outside of a style
  rule in certain circumstances.

* Fix `not` in parentheses in `@supports` conditions.

* Allow `url` as an identifier name.

* Properly parse `/***/` in selectors.

* Properly parse unary operators immediately after commas.

* Match Ruby Sass's rounding behavior for all functions.

* Allow `\` at the beginning of a selector in the indented syntax.

* Fix a number of `@extend` bugs:

  * `selector-extend()` and `selector-replace()` now allow compound selector
    extendees.

  * Remove the universal selector `*` when unifying with other selectors.

  * Properly unify the result of multiple simple selectors in the same compound
    selector being extended.

  * Properly handle extensions being extended.

  * Properly follow the [first law of `@extend`][laws].

  * Fix selector specificity tracking to follow the
    [second law of `@extend`][laws].

  * Allow extensions that match selectors but fail to unify.

  * Partially-extended selectors are no longer used as parent selectors.

  * Fix an edge case where both the extender and the extended selector
    have invalid combinator sequences.

  * Don't crash with a "Bad state: no element" error in certain edge cases.

[laws]: https://github.com/sass/sass/issues/324#issuecomment-4607184

## 1.0.0-alpha.9

* Elements without a namespace (such as `div`) are no longer unified with
  elements with the empty namespace (such as `|div`). This unification didn't
  match the results returned by `is-superselector()`, and was not guaranteed to
  be valid.

* Support `&` within `@at-root`.

* Properly error when a compound selector is followed immediately by `&`.

* Properly handle variable scoping in `@at-root` and nested properties.

* Properly handle placeholder selectors in selector pseudos.

* Properly short-circuit the `or` and `and` operators.

* Support `--$variable`.

* Don't consider unitless numbers equal to numbers with units.

* Warn about using named colors in interpolation.

* Don't emit loud comments in functions.

* Detect import loops.

* Fix `@import` with a `supports()` clause.

* Forbid functions named "and", "or", and "not".

* Fix `type-of()` with a function.

* Emit a nicer error for invalid tokens in a selector.

* Fix `invert()` with a `$weight` parameter.

* Fix a unit-parsing edge-cases.

* Always parse imports with queries as plain CSS imports.

* Support `&` followed by a non-identifier.

* Properly handle split media queries.

* Properly handle a placeholder selector that isn't at the beginning of a
  compound selector.

* Fix more `str-slice()` bugs.

* Fix the `%` operator.

* Allow whitespace between `=` and the mixin name in the indented syntax.

* Fix some slash division edge cases.

* Fix `not` when used like a function.

* Fix attribute selectors with single-character values.

* Fix some bugs with the `call()` function.

* Properly handle a backslash followed by a CRLF sequence in a quoted string.

* Fix numbers divided by colors.

* Support slash-separated numbers in arguments to plain CSS functions.

* Error out if a function is passed an unknown named parameter.

* Improve the speed of loading large files on Node.

* Don't consider browser-prefixed selector pseudos to be superselectors of
  differently- or non-prefixed selector pseudos with the same base name.

* Fix an `@extend` edge case involving multiple combinators in a row.

* Fix a bug where a `@content` block could get incorrectly passed to a mixin.

* Properly isolate the lexical environments of different calls to the same mixin
  and function.

## 1.0.0-alpha.8

* Add the `content-exists()` function.

* Support interpolation in loud comments.

* Fix a bug where even valid semicolons and exclamation marks in custom property
  values were disallowed.

* Disallow invalid function names.

* Disallow extending across media queries.

* Properly parse whitespace after `...` in argument declaration lists.

* Support terse mixin syntax in the indented syntax.

* Fix `@at-root` query parsing.

* Support special functions in `@-moz-document`.

* Support `...` after a digit.

* Fix some bugs when treating a map as a list of pairs.

## 1.0.0-alpha.7

* Fix `function-exists()`, `variable-exists()`, and `mixin-exists()` to use the
  lexical scope rather than always using the global scope.

* `str-index()` now correctly inserts at negative indices.

* Properly parse `url()`s that contain comment-like text.

* Fix a few more small `@extend` bugs.

* Fix a bug where interpolation in a quoted string was being dropped in some
  circumstances.

* Properly handle `@for` rules where each bound has a different unit.

* Forbid mixins and functions from being defined in control directives.

* Fix a superselector-computation edge case involving `:not()`.

* Gracefully handle input files that are invalid UTF-8.

* Print a Sass stack trace when a file fails to load.

## 1.0.0-alpha.6

* Allow `var()` to be passed to `rgb()`, `rgba()`, `hsl()`, and `hsla()`.

* Fix conversions between numbers with `dpi`, `dpcm`, and `dppx` units.
  Previously these conversions were inverted.

* Don't crash when calling `str-slice()` with an `$end-at` index lower than the
  `$start-at` index.

* `str-slice()` now correctly returns `""` when `$end-at` is negative and points
  before the beginning of the string.

* Interpolation in quoted strings now properly preserves newlines.

* Don't crash when passing only `$hue` or no keyword arguments to
  `adjust-color()`, `scale-color()`, or `change-color()`.

* Preserve escapes in identifiers. This used to only work for identifiers in
  SassScript.

* Fix a few small `@extend` bugs.

## 1.0.0-alpha.5

* Fix bounds-checking for `opacify()`, `fade-in()`, `transparentize()`, and
  `fade-out()`.

* Fix a bug with `@extend` superselector calculations.

* Fix some cases where `#{...}--` would fail to parse in selectors.

* Allow a single number to be passed to `saturate()` for use in filter contexts.

* Fix a bug where `**/` would fail to close a loud comment.

* Fix a bug where mixin and function calls could set variables incorrectly.

* Move plain CSS `@import`s to the top of the document.

## 1.0.0-alpha.4

* Add support for bracketed lists.

* Add support for Unicode ranges.

* Add support for the Microsoft-style `=` operator.

* Print the filename for `@debug` rules.

* Fix a bug where `1 + - 2` and similar constructs would crash the parser.

* Fix a bug where `@extend` produced the wrong result when used with
  selector combinators.

* Fix a bug where placeholder selectors were not allowed to be unified.

* Fix the `mixin-exists()` function.

* Fix `:nth-child()` and `:nth-last-child()` parsing when they contain `of
  selector`.

## 1.0.0-alpha.3

* Fix a bug where color equality didn't take the alpha channel into account.

* Fix a bug with converting some RGB colors to HSL.

* Fix a parent selector resolution bug.

* Properly declare the arguments for `opacify()` and related functions.

* Add a missing dependency on the `stack_trace` package.

* Fix broken Windows archives.

* Emit colors using their original representation if possible.

* Emit colors without an original representation as names if possible.

## 1.0.0-alpha.2

* Fix a bug where variables, functions, and mixins were broken in imported
  files.

## 1.0.0-alpha.1

* Initial alpha release.