module Sass::Script::Functions - sass-3.4.14 Documentation

# module Sass::Script::Functions

@comment

    YARD can't handle some multiline tags, and we need really long tags for function declarations.
    rubocop:disable LineLength

Methods in this module are accessible from the SassScript context. For example, you can write

    $color: hsl(120deg, 100%, 50%)

and it will call {Functions#hsl}.

The following functions are provided:

*Note: These functions are described in more detail below.*

## RGB Functions

{#rgb rgb($red, $green, $blue)} : Creates a {Sass::Script::Value::Color Color} from red, green, and blue

    values.

{#rgba rgba($red, $green, $blue, $alpha)} : Creates a {Sass::Script::Value::Color Color} from red, green, blue, and

    alpha values.

{#red red($color)} : Gets the red component of a color.

{#green green($color)} : Gets the green component of a color.

{#blue blue($color)} : Gets the blue component of a color.

{#mix mix($color1, $color2, [$weight])} : Mixes two colors together.

## HSL Functions

{#hsl hsl($hue, $saturation, $lightness)} : Creates a {Sass::Script::Value::Color Color} from hue, saturation, and

    lightness values.

{#hsla hsla($hue, $saturation, $lightness, $alpha)} : Creates a {Sass::Script::Value::Color Color} from hue, saturation,

    lightness, and alpha values.

{#hue hue($color)} : Gets the hue component of a color.

{#saturation saturation($color)} : Gets the saturation component of a color.

{#lightness lightness($color)} : Gets the lightness component of a color.

{#adjust_hue adjust-hue($color, $degrees)} : Changes the hue of a color.

{#lighten lighten($color, $amount)} : Makes a color lighter.

{#darken darken($color, $amount)} : Makes a color darker.

{#saturate saturate($color, $amount)} : Makes a color more saturated.

{#desaturate desaturate($color, $amount)} : Makes a color less saturated.

{#grayscale grayscale($color)} : Converts a color to grayscale.

{#complement complement($color)} : Returns the complement of a color.

{#invert invert($color)} : Returns the inverse of a color.

## Opacity Functions

{#alpha alpha($color)} / {#opacity opacity($color)} : Gets the alpha component (opacity) of a color.

{#rgba rgba($color, $alpha)} : Changes the alpha component for a color.

{#opacify opacify($color, $amount)} / {#fade_in fade-in($color, $amount)} : Makes a color more opaque.

{#transparentize transparentize($color, $amount)} / {#fade_out fade-out($color, $amount)} : Makes a color more transparent.

## Other Color Functions

{#adjust_color adjust-color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha])} : Increases or decreases one or more components of a color.

{#scale_color scale-color($color, [$red], [$green], [$blue], [$saturation], [$lightness], [$alpha])} : Fluidly scales one or more properties of a color.

{#change_color change-color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha])} : Changes one or more properties of a color.

{#ie_hex_str ie-hex-str($color)} : Converts a color into the format understood by IE filters.

## String Functions

{#unquote unquote($string)} : Removes quotes from a string.

{#quote quote($string)} : Adds quotes to a string.

{#str_length str-length($string)} : Returns the number of characters in a string.

{#str_insert str-insert($string, $insert, $index)} : Inserts `$insert` into `$string` at `$index`.

{#str_index str-index($string, $substring)} : Returns the index of the first occurance of `$substring` in `$string`.

{#str_slice str-slice($string, $start-at, [$end-at])} : Extracts a substring from `$string`.

{#to_upper_case to-upper-case($string)} : Converts a string to upper case.

{#to_lower_case to-lower-case($string)} : Converts a string to lower case.

## Number Functions

{#percentage percentage($number)} : Converts a unitless number to a percentage.

{#round round($number)} : Rounds a number to the nearest whole number.

{#ceil ceil($number)} : Rounds a number up to the next whole number.

{#floor floor($number)} : Rounds a number down to the previous whole number.

{#abs abs($number)} : Returns the absolute value of a number.

{#min min($numbers…)} : Finds the minimum of several numbers.

{#max max($numbers…)} : Finds the maximum of several numbers.

{#random random()} : Returns a random number.

## List Functions {#list-functions}

All list functions work for maps as well, treating them as lists of pairs.

{#length length($list)} : Returns the length of a list.

{#nth nth($list, $n)} : Returns a specific item in a list.

{#set-nth set-nth($list, $n, $value)} : Replaces the nth item in a list.

{#join join($list1, $list2, [$separator])} : Joins together two lists into one.

{#append append($list1, $val, [$separator])} : Appends a single value onto the end of a list.

{#zip zip($lists…)} : Combines several lists into a single multidimensional list.

{#index index($list, $value)} : Returns the position of a value within a list.

{#list_separator list-separator(#list)} : Returns the separator of a list.

## Map Functions {#map-functions}

{#map_get map-get($map, $key)} : Returns the value in a map associated with a given key.

{#map_merge map-merge($map1, $map2)} : Merges two maps together into a new map.

{#map_remove map-remove($map, $keys…)} : Returns a new map with keys removed.

{#map_keys map-keys($map)} : Returns a list of all keys in a map.

{#map_values map-values($map)} : Returns a list of all values in a map.

{#map_has_key map-has-key($map, $key)} : Returns whether a map has a value associated with a given key.

{#keywords keywords($args)} : Returns the keywords passed to a function that takes variable arguments.

## Selector Functions

Selector functions are very liberal in the formats they support for selector arguments. They can take a plain string, a list of lists as returned by `&` or anything in between:

- A plain string, such as `“.foo .bar, .baz .bang”`.

- A space-separated list of strings such as `(“.foo” “.bar”)`.

- A comma-separated list of strings such as `(“.foo .bar”, “.baz .bang”)`.

- A comma-separated list of space-separated lists of strings such as `((“.foo” “.bar”), (“.baz” “.bang”))`.

In general, selector functions allow placeholder selectors (`%foo`) but disallow parent-reference selectors (`&`).

{#selector_nest selector-nest($selectors…)} : Nests selector beneath one another like they would be nested in the

    stylesheet.

{#selector_append selector-append($selectors…)} : Appends selectors to one another without spaces in between.

{#selector_extend selector-extend($selector, $extendee, $extender)} : Extends `$extendee` with `$extender` within `$selector`.

{#selector_replace selector-replace($selector, $original, $replacement)} : Replaces `$original` with `$replacement` within `$selector`.

{#selector_unify selector-unify($selector1, $selector2)} : Unifies two selectors to produce a selector that matches

    elements matched by both.

{#is_superselector is-superselector($super, $sub)} : Returns whether `$super` matches all the elements `$sub` does, and

    possibly more.

{#simple_selectors simple-selectors($selector)} : Returns the simple selectors that comprise a compound selector.

{#selector_parse selector-parse($selector)} : Parses a selector into the format returned by `&`.

## Introspection Functions

{#feature_exists feature-exists($feature)} : Returns whether a feature exists in the current Sass runtime.

{#variable_exists variable-exists($name)} : Returns whether a variable with the given name exists in the current scope.

{#global_variable_exists global-variable-exists($name)} : Returns whether a variable with the given name exists in the global scope.

{#function_exists function-exists($name)} : Returns whether a function with the given name exists.

{#mixin_exists mixin-exists($name)} : Returns whether a mixin with the given name exists.

{#inspect inspect($value)} : Returns the string representation of a value as it would be represented in Sass.

{#type_of type-of($value)} : Returns the type of a value.

{#unit unit($number)} : Returns the unit(s) associated with a number.

{#unitless unitless($number)} : Returns whether a number has units.

{#comparable comparable($number1, $number2)} : Returns whether two numbers can be added, subtracted, or compared.

{#call call($name, $args…)} : Dynamically calls a Sass function.

## Miscellaneous Functions

{#if if($condition, $if-true, $if-false)} : Returns one of two values, depending on whether or not `$condition` is

    true.

{#unique_id unique-id()} : Returns a unique CSS identifier.

## Adding Custom Functions

New Sass functions can be added by adding Ruby methods to this module. For example:

    module Sass::Script::Functions
      def reverse(string)
        assert_type string, :String
        Sass::Script::Value::String.new(string.value.reverse)
      end
      declare :reverse, [:string]
    end

Calling {declare} tells Sass the argument names for your function. If omitted, the function will still work, but will not be able to accept keyword arguments. {declare} can also allow your function to take arbitrary keyword arguments.

There are a few things to keep in mind when modifying this module. First of all, the arguments passed are {Value} objects. Value objects are also expected to be returned. This means that Ruby values must be unwrapped and wrapped.

Most Value objects support the {Value::Base#value value} accessor for getting their Ruby values. Color objects, though, must be accessed using {Sass::Script::Value::Color#rgb rgb}, {Sass::Script::Value::Color#red red}, {Sass::Script::Value::Color#blue green}, or {Sass::Script::Value::Color#blue blue}.

Second, making Ruby functions accessible from Sass introduces the temptation to do things like database access within stylesheets. This is generally a bad idea; since Sass files are by default only compiled once, dynamic code is not a great fit.

If you really, really need to compile Sass on each request, first make sure you have adequate caching set up. Then you can use {Sass::Engine} to render the code, using the {file:SASS_REFERENCE.md#custom-option `options` parameter} to pass in data that {EvaluationContext#options can be accessed} from your Sass functions.

Within one of the functions in this module, methods of {EvaluationContext} can be used.

### Caveats

When creating new {Value} objects within functions, be aware that it's not safe to call {Value::Base#to_s to_s} (or other methods that use the string representation) on those objects without first setting {Tree::Node#options= the options attribute}.

@comment

    rubocop:enable LineLength

### Constants

Signature

  A class representing a Sass function signature.

  @attr args [Array<String>] The names of the arguments to the function. @attr delayed_args [Array<String>] The names of the arguments whose evaluation should be

      delayed.

  @attr var_args [Boolean] Whether the function takes a variable number of arguments. @attr var_kwargs [Boolean] Whether the function takes an arbitrary set of keyword arguments.

### Public Class Methods

declare(method_name, args, options = {}) click to toggle source

Declare a Sass signature for a Ruby-defined function. This includes the names of the arguments, whether the function takes a variable number of arguments, and whether the function takes an arbitrary set of keyword arguments.

It's not necessary to declare a signature for a function. However, without a signature it won't support keyword arguments.

A single function can have multiple signatures declared as long as each one takes a different number of arguments. It's also possible to declare multiple signatures that all take the same number of arguments, but none of them but the first will be used unless the user uses keyword arguments.

@example

    declare :rgba, [:hex, :alpha]
    declare :rgba, [:red, :green, :blue, :alpha]
    declare :accepts_anything, [], :var_args => true, :var_kwargs => true
    declare :some_func, [:foo, :bar, :baz], :var_kwargs => true

@param method_name [Symbol] The name of the method

    whose signature is being declared.

@param args [Array<Symbol>] The names of the arguments for the function signature. @option options :var_args [Boolean] (false)

    Whether the function accepts a variable number of (unnamed) arguments
    in addition to the named arguments.

@option options :var_kwargs [Boolean] (false)

    Whether the function accepts other keyword arguments
    in addition to those in `:args`.
    If this is true, the Ruby function will be passed a hash from strings
    to {Value}s as the last argument.
    In addition, if this is true and `:var_args` is not,
    Sass will ensure that the last argument passed is a hash.

    # File lib/sass/script/functions.rb, line 399
    def self.declare(method_name, args, options = {})
      delayed_args = []
      args = args.map do |a|
        a = a.to_s
        if a[0] == ?&
          a = a[1..-1]
          delayed_args << a
        end
        a
      end
      # We don't expose this functionality except to certain builtin methods.
      if delayed_args.any? && method_name != :if
        raise ArgumentError.new("Delayed arguments are not allowed for method #{method_name}")
      end
      @signatures[method_name] ||= []
      @signatures[method_name] << Signature.new(
        args,
        delayed_args,
        options[:var_args],
        options[:var_kwargs],
        options[:deprecated] && options[:deprecated].map {|a| a.to_s})
    end

random_number_generator() click to toggle source

Get Sass's internal random number generator.

@return [Random]

    # File lib/sass/script/functions.rb, line 473
    def self.random_number_generator
      @random_number_generator ||= Sass::Util::CrossPlatformRandom.new
    end

random_seed=(seed) click to toggle source

Sets the random seed used by Sass's internal random number generator.

This can be used to ensure consistent random number sequences which allows for consistent results when testing, etc.

@param seed [Integer] @return [Integer] The same seed.

    # File lib/sass/script/functions.rb, line 466
    def self.random_seed=(seed)
      @random_number_generator = Sass::Util::CrossPlatformRandom.new(seed)
    end

signature(method_name, arg_arity, kwarg_arity) click to toggle source

Determine the correct signature for the number of arguments passed in for a given function. If no signatures match, the first signature is returned for error messaging.

@param method_name [Symbol] The name of the Ruby function to be called. @param arg_arity [Fixnum] The number of unnamed arguments the function was passed. @param kwarg_arity [Fixnum] The number of keyword arguments the function was passed.

@return [{Symbol => Object}, nil]

    The signature options for the matching signature,
    or nil if no signatures are declared for this function. See {declare}.

    # File lib/sass/script/functions.rb, line 433
    def self.signature(method_name, arg_arity, kwarg_arity)
      return unless @signatures[method_name]
      @signatures[method_name].each do |signature|
        sig_arity = signature.args.size
        return signature if sig_arity == arg_arity + kwarg_arity
        next unless sig_arity < arg_arity + kwarg_arity

        # We have enough args.
        # Now we need to figure out which args are varargs
        # and if the signature allows them.
        t_arg_arity, t_kwarg_arity = arg_arity, kwarg_arity
        if sig_arity > t_arg_arity
          # we transfer some kwargs arity to args arity
          # if it does not have enough args -- assuming the names will work out.
          t_kwarg_arity -= (sig_arity - t_arg_arity)
          t_arg_arity = sig_arity
        end

        if   (t_arg_arity == sig_arity ||   t_arg_arity > sig_arity && signature.var_args) &&
           (t_kwarg_arity == 0         || t_kwarg_arity > 0         && signature.var_kwargs)
          return signature
        end
      end
      @signatures[method_name].first
    end

### Private Class Methods

include(*args) click to toggle source
Calls superclass method

    # File lib/sass/script/functions.rb, line 601
    def include(*args)
      r = super
      # We have to re-include ourselves into EvaluationContext to work around
      # an icky Ruby restriction.
      EvaluationContext.send :include, self
      r
    end

### Public Instance Methods

abs(number) click to toggle source

Returns the absolute value of a number.

@example

    abs(10px) => 10px
    abs(-10px) => 10px

@overload abs($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1760
    def abs(number)
      numeric_transformation(number) {|n| n.abs}
    end

adjust_color(color, kwargs) click to toggle source

Increases or decreases one or more properties of a color. This can change the red, green, blue, hue, saturation, value, and alpha properties. The properties are specified as keyword arguments, and are added to or subtracted from the color's current value for that property.

All properties are optional. You can't specify both RGB properties (`$red`, `$green`, `$blue`) and HSL properties (`$hue`, `$saturation`, `$value`) at the same time.

@example

    adjust-color(#102030, $blue: 5) => #102035
    adjust-color(#102030, $red: -5, $blue: 5) => #0b2035
    adjust-color(hsl(25, 100%, 80%), $lightness: -30%, $alpha: -0.4) => hsla(25, 100%, 50%, 0.6)

@comment

    rubocop:disable LineLength

@overload #adjust_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha])

    @comment
      rubocop:disable LineLength
    @param $color [Sass::Script::Value::Color]
    @param $red [Sass::Script::Value::Number] The adjustment to make on the
      red component, between -255 and 255 inclusive
    @param $green [Sass::Script::Value::Number] The adjustment to make on the
      green component, between -255 and 255 inclusive
    @param $blue [Sass::Script::Value::Number] The adjustment to make on the
      blue component, between -255 and 255 inclusive
    @param $hue [Sass::Script::Value::Number] The adjustment to make on the
      hue component, in degrees
    @param $saturation [Sass::Script::Value::Number] The adjustment to make on
      the saturation component, between `-100%` and `100%` inclusive
    @param $lightness [Sass::Script::Value::Number] The adjustment to make on
      the lightness component, between `-100%` and `100%` inclusive
    @param $alpha [Sass::Script::Value::Number] The adjustment to make on the
      alpha component, between -1 and 1 inclusive

@return [Sass::Script::Value::Color] @raise [ArgumentError] if any parameter is the wrong type or out-of

    bounds, or if RGB properties and HSL properties are adjusted at the
    same time

    # File lib/sass/script/functions.rb, line 1102
    def adjust_color(color, kwargs)
      assert_type color, :Color, :color
      with = Sass::Util.map_hash(
          "red" => [-255..255, ""],
          "green" => [-255..255, ""],
          "blue" => [-255..255, ""],
          "hue" => nil,
          "saturation" => [-100..100, "%"],
          "lightness" => [-100..100, "%"],
          "alpha" => [-1..1, ""]
        ) do |name, (range, units)|

        val = kwargs.delete(name)
        next unless val
        assert_type val, :Number, name
        Sass::Util.check_range("$#{name}: Amount", range, val, units) if range
        adjusted = color.send(name) + val.value
        adjusted = [0, Sass::Util.restrict(adjusted, range)].max if range
        [name.to_sym, adjusted]
      end

      unless kwargs.empty?
        name, val = kwargs.to_a.first
        raise ArgumentError.new("Unknown argument $#{name} (#{val})")
      end

      color.with(with)
    end

adjust_hue(color, degrees) click to toggle source

Changes the hue of a color. Takes a color and a number of degrees (usually between `-360deg` and `360deg`), and returns a color with the hue rotated along the color wheel by that amount.

@example

    adjust-hue(hsl(120, 30%, 90%), 60deg) => hsl(180, 30%, 90%)
    adjust-hue(hsl(120, 30%, 90%), -60deg) => hsl(60, 30%, 90%)
    adjust-hue(#811, 45deg) => #886a11

@overload #adjust_hue($color, $degrees)

    @param $color [Sass::Script::Value::Color]
    @param $degrees [Sass::Script::Value::Number] The number of degrees to
      rotate the hue

@return [Sass::Script::Value::Color] @raise [ArgumentError] if either parameter is the wrong type

    # File lib/sass/script/functions.rb, line 1040
    def adjust_hue(color, degrees)
      assert_type color, :Color, :color
      assert_type degrees, :Number, :degrees
      color.with(:hue => color.hue + degrees.value)
    end

alpha(*args) click to toggle source

Returns the alpha component (opacity) of a color. This is 1 unless otherwise specified.

This function also supports the proprietary Microsoft `alpha(opacity=20)` syntax as a special case.

@overload alpha($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The alpha component, between 0 and 1 @raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 870
    def alpha(*args)
      if args.all? do |a|
           a.is_a?(Sass::Script::Value::String) && a.type == :identifier &&
             a.value =~ /^[a-zA-Z]+\s*=/
         end
        # Support the proprietary MS alpha() function
        return identifier("alpha(#{args.map {|a| a.to_s}.join(", ")})")
      end

      raise ArgumentError.new("wrong number of arguments (#{args.size} for 1)") if args.size != 1

      assert_type args.first, :Color, :color
      number(args.first.alpha)
    end

append(list, val, separator = identifier("auto")) click to toggle source

Appends a single value onto the end of a list.

Unless the `$separator` argument is passed, if the list had only one item, the resulting list will be space-separated.

@example

    append(10px 20px, 30px) => 10px 20px 30px
    append((blue, red), green) => blue, red, green
    append(10px 20px, 30px 40px) => 10px 20px (30px 40px)
    append(10px, 20px, comma) => 10px, 20px
    append((blue, red), green, space) => blue red green

@overload append($list, $val, $separator: auto)

    @param $list [Sass::Script::Value::Base]
    @param $val [Sass::Script::Value::Base]
    @param $separator [Sass::Script::Value::String] The list separator to use.
      If this is `comma` or `space`, that separator will be used. If this is
      `auto` (the default), the separator is determined as explained above.

@return [Sass::Script::Value::List]

    # File lib/sass/script/functions.rb, line 1928
    def append(list, val, separator = identifier("auto"))
      assert_type separator, :String, :separator
      unless %w[auto space comma].include?(separator.value)
        raise ArgumentError.new("Separator name must be space, comma, or auto")
      end
      sep = if separator.value == 'auto'
              list.separator || :space
            else
              separator.value.to_sym
            end
      list(list.to_a + [val], sep)
    end

blue(color) click to toggle source

Gets the blue component of a color. Calculated from HSL where necessary via [this algorithm].

[hsl-to-rgb]: www.w3.org/TR/css3-color/#hsl-color

@overload blue($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The blue component, between 0 and

    255 inclusive

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 800
    def blue(color)
      assert_type color, :Color, :color
      number(color.blue)
    end

call(name, *args) click to toggle source

Dynamically calls a function. This can call user-defined functions, built-in functions, or plain CSS functions. It will pass along all arguments, including keyword arguments, to the called function.

@example

    call(rgb, 10, 100, 255) => #0a64ff
    call(scale-color, #0a64ff, $lightness: -10%) => #0058ef

    $fn: nth;
    call($fn, (a b c), 2) => b

@overload call($name, $args…)

    @param $name [String] The name of the function to call.

    # File lib/sass/script/functions.rb, line 2190
    def call(name, *args)
      assert_type name, :String, :name
      kwargs = args.last.is_a?(Hash) ? args.pop : {}
      funcall = Sass::Script::Tree::Funcall.new(
        name.value,
        args.map {|a| Sass::Script::Tree::Literal.new(a)},
        Sass::Util.map_vals(kwargs) {|v| Sass::Script::Tree::Literal.new(v)},
        nil,
        nil)
      funcall.options = options
      perform(funcall)
    end

ceil(number) click to toggle source

Rounds a number up to the next whole number.

@example

    ceil(10.4px) => 11px
    ceil(10.6px) => 11px

@overload ceil($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1732
    def ceil(number)
      numeric_transformation(number) {|n| n.ceil}
    end

change_color(color, kwargs) click to toggle source

Changes one or more properties of a color. This can change the red, green, blue, hue, saturation, value, and alpha properties. The properties are specified as keyword arguments, and replace the color's current value for that property.

All properties are optional. You can't specify both RGB properties (`$red`, `$green`, `$blue`) and HSL properties (`$hue`, `$saturation`, `$value`) at the same time.

@example

    change-color(#102030, $blue: 5) => #102005
    change-color(#102030, $red: 120, $blue: 5) => #782005
    change-color(hsl(25, 100%, 80%), $lightness: 40%, $alpha: 0.8) => hsla(25, 100%, 40%, 0.8)

@comment

    rubocop:disable LineLength

@overload #change_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha])

    @comment
      rubocop:disable LineLength
    @param $color [Sass::Script::Value::Color]
    @param $red [Sass::Script::Value::Number] The new red component for the
      color, within 0 and 255 inclusive
    @param $green [Sass::Script::Value::Number] The new green component for
      the color, within 0 and 255 inclusive
    @param $blue [Sass::Script::Value::Number] The new blue component for the
      color, within 0 and 255 inclusive
    @param $hue [Sass::Script::Value::Number] The new hue component for the
      color, in degrees
    @param $saturation [Sass::Script::Value::Number] The new saturation
      component for the color, between `0%` and `100%` inclusive
    @param $lightness [Sass::Script::Value::Number] The new lightness
      component for the color, within `0%` and `100%` inclusive
    @param $alpha [Sass::Script::Value::Number] The new alpha component for
      the color, within 0 and 1 inclusive

@return [Sass::Script::Value::Color] @raise [ArgumentError] if any parameter is the wrong type or out-of

    bounds, or if RGB properties and HSL properties are adjusted at the
    same time

    # File lib/sass/script/functions.rb, line 1244
    def change_color(color, kwargs)
      assert_type color, :Color, :color
      with = Sass::Util.map_hash(
        'red' => ['Red value', 0..255],
        'green' => ['Green value', 0..255],
        'blue' => ['Blue value', 0..255],
        'hue' => [],
        'saturation' => ['Saturation', 0..100, '%'],
        'lightness' => ['Lightness', 0..100, '%'],
        'alpha' => ['Alpha channel', 0..1]
      ) do |name, (desc, range, unit)|
        val = kwargs.delete(name)
        next unless val
        assert_type val, :Number, name

        if range
          val = Sass::Util.check_range(desc, range, val, unit)
        else
          val = val.value
        end

        [name.to_sym, val]
      end

      unless kwargs.empty?
        name, val = kwargs.to_a.first
        raise ArgumentError.new("Unknown argument $#{name} (#{val})")
      end

      color.with(with)
    end

comparable(number1, number2) click to toggle source

Returns whether two numbers can added, subtracted, or compared.

@example

    comparable(2px, 1px) => true
    comparable(100px, 3em) => false
    comparable(10cm, 3mm) => true

@overload comparable($number1, $number2)

    @param $number1 [Sass::Script::Value::Number]
    @param $number2 [Sass::Script::Value::Number]

@return [Sass::Script::Value::Bool] @raise [ArgumentError] if either parameter is the wrong type

    # File lib/sass/script/functions.rb, line 1685
    def comparable(number1, number2)
      assert_type number1, :Number, :number1
      assert_type number2, :Number, :number2
      bool(number1.comparable_to?(number2))
    end

complement(color) click to toggle source

Returns the complement of a color. This is identical to `adjust-hue(color, 180deg)`.

@see adjust_hue adjust-hue @overload complement($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 1363
    def complement(color)
      adjust_hue color, number(180)
    end

counter(*args) click to toggle source

This function only exists as a workaround for IE7's [`content: counter` bug](jes.st/2013/ie7s-css-breaking-content-counter-bug/). It works identically to any other plain-CSS function, except it avoids adding spaces between the argument commas.

@example

    counter(item, ".") => counter(item,".")

@overload counter($args…) @return [Sass::Script::Value::String]

    # File lib/sass/script/functions.rb, line 2213
    def counter(*args)
      identifier("counter(#{args.map {|a| a.to_s(options)}.join(',')})")
    end

counters(*args) click to toggle source

This function only exists as a workaround for IE7's [`content: counter` bug](jes.st/2013/ie7s-css-breaking-content-counter-bug/). It works identically to any other plain-CSS function, except it avoids adding spaces between the argument commas.

@example

    counters(item, ".") => counters(item,".")

@overload counters($args…) @return [Sass::Script::Value::String]

    # File lib/sass/script/functions.rb, line 2227
    def counters(*args)
      identifier("counters(#{args.map {|a| a.to_s(options)}.join(',')})")
    end

darken(color, amount) click to toggle source

Makes a color darker. Takes a color and a number between 0% and 100%, and returns a color with the lightness decreased by that amount.

@see lighten @example

    darken(hsl(25, 100%, 80%), 30%) => hsl(25, 100%, 50%)
    darken(#800, 20%) => #200

@overload darken($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to decrease the
      lightness by, between `0%` and `100%`

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 979
    def darken(color, amount)
      _adjust(color, amount, :lightness, 0..100, :-, "%")
    end

desaturate(color, amount) click to toggle source

Makes a color less saturated. Takes a color and a number between 0% and 100%, and returns a color with the saturation decreased by that value.

@see saturate @example

    desaturate(hsl(120, 30%, 90%), 20%) => hsl(120, 10%, 90%)
    desaturate(#855, 20%) => #726b6b

@overload desaturate($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to decrease the
      saturation by, between `0%` and `100%`

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 1021
    def desaturate(color, amount)
      _adjust(color, amount, :saturation, 0..100, :-, "%")
    end

fade_in(color, amount)
Alias for: opacify
fade_out(color, amount)
Alias for: transparentize
feature_exists(feature) click to toggle source

Returns whether a feature exists in the current Sass runtime.

The following features are supported:

- `global-variable-shadowing` indicates that a local variable will shadow a global variable unless `!global` is used.

- `extend-selector-pseudoclass` indicates that `@extend` will reach into selector pseudoclasses like `:not`.

- `units-level-3` indicates full support for unit arithmetic using units defined in the [Values and Units Level 3][] spec.

[Values and Units Level 3]: www.w3.org/TR/css3-values/

- `at-error` indicates that the Sass `@error` directive is supported.

@example

    feature-exists(some-feature-that-exists) => true
    feature-exists(what-is-this-i-dont-know) => false

@overload #feature_exists($feature)

    @param $feature [Sass::Script::Value::String] The name of the feature

@return [Sass::Script::Value::Bool] Whether the feature is supported in this version of Sass @raise [ArgumentError] if `$feature` isn't a string

    # File lib/sass/script/functions.rb, line 1633
    def feature_exists(feature)
      assert_type feature, :String, :feature
      bool(Sass.has_feature?(feature.value))
    end

floor(number) click to toggle source

Rounds a number down to the previous whole number.

@example

    floor(10.4px) => 10px
    floor(10.6px) => 10px

@overload floor($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1746
    def floor(number)
      numeric_transformation(number) {|n| n.floor}
    end

function_exists(name) click to toggle source

Check whether a function with the given name exists.

@example

    function-exists(lighten) => true

    @function myfunc { @return "something"; }
    function-exists(myfunc) => true

@overload #function_exists($name)

    @param name [Sass::Script::Value::String] The name of the function to
      check.

@return [Sass::Script::Value::Bool] Whether the function is defined.

    # File lib/sass/script/functions.rb, line 2287
    def function_exists(name)
      assert_type name, :String, :name
      exists = Sass::Script::Functions.callable?(name.value.tr("-", "_"))
      exists ||= environment.function(name.value)
      bool(exists)
    end

global_variable_exists(name) click to toggle source

Check whether a variable with the given name exists in the global scope (at the top level of the file).

@example

    $a-false-value: false;
    global-variable-exists(a-false-value) => true

    .foo {
      $some-var: false;
      @if global-variable-exists(some-var) {    false, doesn't run    }
    }

@overload #global_variable_exists($name)

    @param $name [Sass::Script::Value::String] The name of the variable to
      check. The name should not include the `$`.

@return [Sass::Script::Value::Bool] Whether the variable is defined in

    the global scope.

    # File lib/sass/script/functions.rb, line 2269
    def global_variable_exists(name)
      assert_type name, :String, :name
      bool(environment.global_env.var(name.value))
    end

grayscale(color) click to toggle source

Converts a color to grayscale. This is identical to `desaturate(color, 100%)`.

@see desaturate @overload grayscale($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 1347
    def grayscale(color)
      if color.is_a?(Sass::Script::Value::Number)
        return identifier("grayscale(#{color})")
      end
      desaturate color, number(100)
    end

green(color) click to toggle source

Gets the green component of a color. Calculated from HSL where necessary via [this algorithm].

[hsl-to-rgb]: www.w3.org/TR/css3-color/#hsl-color

@overload green($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The green component, between 0 and

    255 inclusive

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 784
    def green(color)
      assert_type color, :Color, :color
      number(color.green)
    end

hsl(hue, saturation, lightness) click to toggle source

Creates a {Sass::Script::Value::Color Color} from hue, saturation, and lightness values. Uses the algorithm from the [CSS3 spec][].

[CSS3 spec]: www.w3.org/TR/css3-color/#hsl-color

@see hsla @overload hsl($hue, $saturation, $lightness)

    @param $hue [Sass::Script::Value::Number] The hue of the color. Should be
      between 0 and 360 degrees, inclusive
    @param $saturation [Sass::Script::Value::Number] The saturation of the
      color. Must be between `0%` and `100%`, inclusive
    @param $lightness [Sass::Script::Value::Number] The lightness of the
      color. Must be between `0%` and `100%`, inclusive

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$saturation` or `$lightness` are out of bounds

    or any parameter is the wrong type

    # File lib/sass/script/functions.rb, line 715
    def hsl(hue, saturation, lightness)
      hsla(hue, saturation, lightness, number(1))
    end

hsla(hue, saturation, lightness, alpha) click to toggle source

Creates a {Sass::Script::Value::Color Color} from hue, saturation, lightness, and alpha values. Uses the algorithm from the [CSS3 spec][].

[CSS3 spec]: www.w3.org/TR/css3-color/#hsl-color

@see hsl @overload hsla($hue, $saturation, $lightness, $alpha)

    @param $hue [Sass::Script::Value::Number] The hue of the color. Should be
      between 0 and 360 degrees, inclusive
    @param $saturation [Sass::Script::Value::Number] The saturation of the
      color. Must be between `0%` and `100%`, inclusive
    @param $lightness [Sass::Script::Value::Number] The lightness of the
      color. Must be between `0%` and `100%`, inclusive
    @param $alpha [Sass::Script::Value::Number] The opacity of the color. Must
      be between 0 and 1, inclusive

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$saturation`, `$lightness`, or `$alpha` are out

    of bounds or any parameter is the wrong type

    # File lib/sass/script/functions.rb, line 739
    def hsla(hue, saturation, lightness, alpha)
      assert_type hue, :Number, :hue
      assert_type saturation, :Number, :saturation
      assert_type lightness, :Number, :lightness
      assert_type alpha, :Number, :alpha
      check_alpha_unit alpha, 'hsla'

      h = hue.value
      s = saturation.value
      l = lightness.value

      # Don't store the string representation for function-created colors, both
      # because it's not very useful and because some functions aren't supported
      # on older browsers.
      Sass::Script::Value::Color.new(
        :hue => h, :saturation => s, :lightness => l, :alpha => alpha.value)
    end

hue(color) click to toggle source

Returns the hue component of a color. See [the CSS3 HSL specification]. Calculated from RGB where necessary via [this algorithm].

[hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV [rgb-to-hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV

@overload hue($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The hue component, between 0deg and

    360deg

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 818
    def hue(color)
      assert_type color, :Color, :color
      number(color.hue, "deg")
    end

ie_hex_str(color) click to toggle source

Converts a color into the format understood by IE filters.

@example

    ie-hex-str(#abc) => #FFAABBCC
    ie-hex-str(#3322BB) => #FF3322BB
    ie-hex-str(rgba(0, 255, 0, 0.5)) => #8000FF00

@overload #ie_hex_str($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::String] The IE-formatted string

    representation of the color

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 1058
    def ie_hex_str(color)
      assert_type color, :Color, :color
      alpha = (color.alpha * 255).round.to_s(16).rjust(2, '0')
      identifier("##{alpha}#{color.send(:hex_str)[1..-1]}".upcase)
    end

if(condition, if_true, if_false) click to toggle source

Returns one of two values, depending on whether or not `$condition` is true. Just like in `@if`, all values other than `false` and `null` are considered to be true.

@example

    if(true, 1px, 2px) => 1px
    if(false, 1px, 2px) => 2px

@overload if($condition, $if-true, $if-false)

    @param $condition [Sass::Script::Value::Base] Whether the `$if-true` or
      `$if-false` will be returned
    @param $if-true [Sass::Script::Tree::Node]
    @param $if-false [Sass::Script::Tree::Node]

@return [Sass::Script::Value::Base] `$if-true` or `$if-false`

    # File lib/sass/script/functions.rb, line 2151
    def if(condition, if_true, if_false)
      if condition.to_bool
        perform(if_true)
      else
        perform(if_false)
      end
    end

index(list, value) click to toggle source

Returns the position of a value within a list. If the value isn't found, returns `null` instead.

Note that unlike some languages, the first item in a Sass list is number 1, the second number 2, and so forth.

This can return the position of a pair in a map as well.

@example

    index(1px solid red, solid) => 2
    index(1px solid red, dashed) => null
    index((width: 10px, height: 20px), (height 20px)) => 2

@overload index($list, $value)

    @param $list [Sass::Script::Value::Base]
    @param $value [Sass::Script::Value::Base]

@return [Sass::Script::Value::Number, Sass::Script::Value::Null] The

    1-based index of `$value` in `$list`, or `null`

    # File lib/sass/script/functions.rb, line 1989
    def index(list, value)
      index = list.to_a.index {|e| e.eq(value).to_bool}
      index ? number(index + 1) : null
    end

inspect(value) click to toggle source

Return a string containing the value as its Sass representation.

@overload inspect($value)

    @param $value [Sass::Script::Value::Base] The value to inspect.

@return [Sass::Script::Value::String] A representation of the value as

    it would be written in Sass.

    # File lib/sass/script/functions.rb, line 2319
    def inspect(value)
      unquoted_string(value.to_sass)
    end

invert(color) click to toggle source

Returns the inverse (negative) of a color. The red, green, and blue values are inverted, while the opacity is left alone.

@overload invert($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 1375
    def invert(color)
      if color.is_a?(Sass::Script::Value::Number)
        return identifier("invert(#{color})")
      end

      assert_type color, :Color, :color
      color.with(
        :red => (255 - color.red),
        :green => (255 - color.green),
        :blue => (255 - color.blue))
    end

is_superselector(sup, sub) click to toggle source

Returns whether `$super` is a superselector of `$sub`. This means that `$super` matches all the elements that `$sub` matches, as well as possibly additional elements. In general, simpler selectors tend to be superselectors of more complex oned.

@example

    is-superselector(".foo", ".foo.bar") => true
    is-superselector(".foo.bar", ".foo") => false
    is-superselector(".bar", ".foo .bar") => true
    is-superselector(".foo .bar", ".bar") => false

@overload #is_superselector($super, $sub)

    @param $super [Sass::Script::Value::String, Sass::Script::Value::List]
      The potential superselector. This can be either a string, a list of
      strings, or a list of lists of strings as returned by `&`.
    @param $sub [Sass::Script::Value::String, Sass::Script::Value::List]
      The potential subselector. This can be either a string, a list of
      strings, or a list of lists of strings as returned by `&`.
    @return [Sass::Script::Value::Bool]
      Whether `$selector1` is a superselector of `$selector2`.

    # File lib/sass/script/functions.rb, line 2616
    def is_superselector(sup, sub)
      sup = parse_selector(sup, :super)
      sub = parse_selector(sub, :sub)
      bool(sup.superselector?(sub))
    end

join(list1, list2, separator = identifier("auto")) click to toggle source

Joins together two lists into one.

Unless `$separator` is passed, if one list is comma-separated and one is space-separated, the first parameter's separator is used for the resulting list. If both lists have fewer than two items, spaces are used for the resulting list.

@example

    join(10px 20px, 30px 40px) => 10px 20px 30px 40px
    join((blue, red), (#abc, #def)) => blue, red, #abc, #def
    join(10px, 20px) => 10px 20px
    join(10px, 20px, comma) => 10px, 20px
    join((blue, red), (#abc, #def), space) => blue red #abc #def

@overload join($list1, $list2, $separator: auto)

    @param $list1 [Sass::Script::Value::Base]
    @param $list2 [Sass::Script::Value::Base]
    @param $separator [Sass::Script::Value::String] The list separator to use.
      If this is `comma` or `space`, that separator will be used. If this is
      `auto` (the default), the separator is determined as explained above.

@return [Sass::Script::Value::List]

    # File lib/sass/script/functions.rb, line 1895
    def join(list1, list2, separator = identifier("auto"))
      assert_type separator, :String, :separator
      unless %w[auto space comma].include?(separator.value)
        raise ArgumentError.new("Separator name must be space, comma, or auto")
      end
      sep = if separator.value == 'auto'
              list1.separator || list2.separator || :space
            else
              separator.value.to_sym
            end
      list(list1.to_a + list2.to_a, sep)
    end

keywords(args) click to toggle source

Returns the map of named arguments passed to a function or mixin that takes a variable argument list. The argument names are strings, and they do not contain the leading `$`.

@example

    @mixin foo($args...) {
      @debug keywords($args); //=> (arg1: val, arg2: val)
    }

    @include foo($arg1: val, $arg2: val);

@overload keywords($args)

    @param $args [Sass::Script::Value::ArgList]

@return [Sass::Script::Value::Map] @raise [ArgumentError] if `$args` isn't a variable argument list

    # File lib/sass/script/functions.rb, line 2132
    def keywords(args)
      assert_type args, :ArgList, :args
      map(Sass::Util.map_keys(args.keywords.as_stored) {|k| Sass::Script::Value::String.new(k)})
    end

length(list) click to toggle source

Return the length of a list.

This can return the number of pairs in a map as well.

@example

    length(10px) => 1
    length(10px 20px 30px) => 3
    length((width: 10px, height: 20px)) => 2

@overload length($list)

    @param $list [Sass::Script::Value::Base]

@return [Sass::Script::Value::Number]

    # File lib/sass/script/functions.rb, line 1810
    def length(list)
      number(list.to_a.size)
    end

lighten(color, amount) click to toggle source

Makes a color lighter. Takes a color and a number between `0%` and `100%`, and returns a color with the lightness increased by that amount.

@see darken @example

    lighten(hsl(0, 0%, 0%), 30%) => hsl(0, 0, 30)
    lighten(#800, 20%) => #e00

@overload lighten($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to increase the
      lightness by, between `0%` and `100%`

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 960
    def lighten(color, amount)
      _adjust(color, amount, :lightness, 0..100, :+, "%")
    end

lightness(color) click to toggle source

Returns the lightness component of a color. See [the CSS3 HSL specification]. Calculated from RGB where necessary via [this algorithm].

[hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV [rgb-to-hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV

@overload lightness($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The lightness component, between 0%

    and 100%

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 854
    def lightness(color)
      assert_type color, :Color, :color
      number(color.lightness, "%")
    end

list_separator(list) click to toggle source

Returns the separator of a list. If the list doesn't have a separator due to having fewer than two elements, returns `space`.

@example

    list-separator(1px 2px 3px) => space
    list-separator(1px, 2px, 3px) => comma
    list-separator('foo') => space

@overload #list_separator($list)

    @param $list [Sass::Script::Value::Base]

@return [Sass::Script::Value::String] `comma` or `space`

    # File lib/sass/script/functions.rb, line 2005
    def list_separator(list)
      identifier((list.separator || :space).to_s)
    end

map_get(map, key) click to toggle source

Returns the value in a map associated with the given key. If the map doesn't have such a key, returns `null`.

@example

    map-get(("foo": 1, "bar": 2), "foo") => 1
    map-get(("foo": 1, "bar": 2), "bar") => 2
    map-get(("foo": 1, "bar": 2), "baz") => null

@overload #map_get($map, $key)

    @param $map [Sass::Script::Value::Map]
    @param $key [Sass::Script::Value::Base]

@return [Sass::Script::Value::Base] The value indexed by `$key`, or `null`

    if the map doesn't contain the given key

@raise [ArgumentError] if `$map` is not a map

    # File lib/sass/script/functions.rb, line 2023
    def map_get(map, key)
      assert_type map, :Map, :map
      map.to_h[key] || null
    end

map_has_key(map, key) click to toggle source

Returns whether a map has a value associated with a given key.

@example

    map-has-key(("foo": 1, "bar": 2), "foo") => true
    map-has-key(("foo": 1, "bar": 2), "baz") => false

@overload #map_has_key($map, $key)

    @param $map [Sass::Script::Value::Map]
    @param $key [Sass::Script::Value::Base]

@return [Sass::Script::Value::Bool] @raise [ArgumentError] if `$map` is not a map

    # File lib/sass/script/functions.rb, line 2112
    def map_has_key(map, key)
      assert_type map, :Map, :map
      bool(map.to_h.has_key?(key))
    end

map_keys(map) click to toggle source

Returns a list of all keys in a map.

@example

    map-keys(("foo": 1, "bar": 2)) => "foo", "bar"

@overload #map_keys($map)

    @param $map [Map]

@return [List] the list of keys, comma-separated @raise [ArgumentError] if `$map` is not a map

    # File lib/sass/script/functions.rb, line 2080
    def map_keys(map)
      assert_type map, :Map, :map
      list(map.to_h.keys, :comma)
    end

map_merge(map1, map2) click to toggle source

Merges two maps together into a new map. Keys in `$map2` will take precedence over keys in `$map1`.

This is the best way to add new values to a map.

All keys in the returned map that also appear in `$map1` will have the same order as in `$map1`. New keys from `$map2` will be placed at the end of the map.

@example

    map-merge(("foo": 1), ("bar": 2)) => ("foo": 1, "bar": 2)
    map-merge(("foo": 1, "bar": 2), ("bar": 3)) => ("foo": 1, "bar": 3)

@overload #map_merge($map1, $map2)

    @param $map1 [Sass::Script::Value::Map]
    @param $map2 [Sass::Script::Value::Map]

@return [Sass::Script::Value::Map] @raise [ArgumentError] if either parameter is not a map

    # File lib/sass/script/functions.rb, line 2046
    def map_merge(map1, map2)
      assert_type map1, :Map, :map1
      assert_type map2, :Map, :map2
      map(map1.to_h.merge(map2.to_h))
    end

map_remove(map, *keys) click to toggle source

Returns a new map with keys removed.

@example

    map-remove(("foo": 1, "bar": 2), "bar") => ("foo": 1)
    map-remove(("foo": 1, "bar": 2, "baz": 3), "bar", "baz") => ("foo": 1)
    map-remove(("foo": 1, "bar": 2), "baz") => ("foo": 1, "bar": 2)

@overload #map_remove($map, $keys…)

    @param $map  [Sass::Script::Value::Map]
    @param $keys [[Sass::Script::Value::Base]]

@return [Sass::Script::Value::Map] @raise [ArgumentError] if `$map` is not a map

    # File lib/sass/script/functions.rb, line 2064
    def map_remove(map, *keys)
      assert_type map, :Map, :map
      hash = map.to_h.dup
      hash.delete_if {|key, _| keys.include?(key)}
      map(hash)
    end

map_values(map) click to toggle source

Returns a list of all values in a map. This list may include duplicate values, if multiple keys have the same value.

@example

    map-values(("foo": 1, "bar": 2)) => 1, 2
    map-values(("foo": 1, "bar": 2, "baz": 1)) => 1, 2, 1

@overload #map_values($map)

    @param $map [Map]

@return [List] the list of values, comma-separated @raise [ArgumentError] if `$map` is not a map

    # File lib/sass/script/functions.rb, line 2096
    def map_values(map)
      assert_type map, :Map, :map
      list(map.to_h.values, :comma)
    end

max(*values) click to toggle source

Finds the maximum of several numbers. This function takes any number of arguments.

@example

    max(1px, 4px) => 4px
    max(5em, 3em, 4em) => 5em

@overload max($numbers…)

    @param $numbers [[Sass::Script::Value::Number]]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if any argument isn't a number, or if not all of

    the arguments have comparable units

    # File lib/sass/script/functions.rb, line 1793
    def max(*values)
      values.each {|v| assert_type v, :Number}
      values.inject {|max, val| max.gt(val).to_bool ? max : val}
    end

min(*numbers) click to toggle source

Finds the minimum of several numbers. This function takes any number of arguments.

@example

    min(1px, 4px) => 1px
    min(5em, 3em, 4em) => 3em

@overload min($numbers…)

    @param $numbers [[Sass::Script::Value::Number]]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if any argument isn't a number, or if not all of

    the arguments have comparable units

    # File lib/sass/script/functions.rb, line 1776
    def min(*numbers)
      numbers.each {|n| assert_type n, :Number}
      numbers.inject {|min, num| min.lt(num).to_bool ? min : num}
    end

mix(color1, color2, weight = number(50)) click to toggle source

Mixes two colors together. Specifically, takes the average of each of the RGB components, optionally weighted by the given percentage. The opacity of the colors is also considered when weighting the components.

The weight specifies the amount of the first color that should be included in the returned color. The default, `50%`, means that half the first color and half the second color should be used. `25%` means that a quarter of the first color and three quarters of the second color should be used.

@example

    mix(#f00, #00f) => #7f007f
    mix(#f00, #00f, 25%) => #3f00bf
    mix(rgba(255, 0, 0, 0.5), #00f) => rgba(63, 0, 191, 0.75)

@overload mix($color1, $color2, $weight: 50%)

    @param $color1 [Sass::Script::Value::Color]
    @param $color2 [Sass::Script::Value::Color]
    @param $weight [Sass::Script::Value::Number] The relative weight of each
      color. Closer to `0%` gives more weight to `$color1`, closer to `100%`
      gives more weight to `$color2`

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$weight` is out of bounds or any parameter is

    the wrong type

    # File lib/sass/script/functions.rb, line 1299
    def mix(color1, color2, weight = number(50))
      assert_type color1, :Color, :color1
      assert_type color2, :Color, :color2
      assert_type weight, :Number, :weight

      Sass::Util.check_range("Weight", 0..100, weight, '%')

      # This algorithm factors in both the user-provided weight (w) and the
      # difference between the alpha values of the two colors (a) to decide how
      # to perform the weighted average of the two RGB values.
      #
      # It works by first normalizing both parameters to be within [-1, 1],
      # where 1 indicates "only use color1", -1 indicates "only use color2", and
      # all values in between indicated a proportionately weighted average.
      #
      # Once we have the normalized variables w and a, we apply the formula
      # (w + a)/(1 + w*a) to get the combined weight (in [-1, 1]) of color1.
      # This formula has two especially nice properties:
      #
      #   * When either w or a are -1 or 1, the combined weight is also that number
      #     (cases where w * a == -1 are undefined, and handled as a special case).
      #
      #   * When a is 0, the combined weight is w, and vice versa.
      #
      # Finally, the weight of color1 is renormalized to be within [0, 1]
      # and the weight of color2 is given by 1 minus the weight of color1.
      p = (weight.value / 100.0).to_f
      w = p * 2 - 1
      a = color1.alpha - color2.alpha

      w1 = ((w * a == -1 ? w : (w + a) / (1 + w * a)) + 1) / 2.0
      w2 = 1 - w1

      rgba = color1.rgb.zip(color2.rgb).map {|v1, v2| v1 * w1 + v2 * w2}
      rgba << color1.alpha * p + color2.alpha * (1 - p)
      rgb_color(*rgba)
    end

mixin_exists(name) click to toggle source

Check whether a mixin with the given name exists.

@example

    mixin-exists(nonexistent) => false

    @mixin red-text { color: red; }
    mixin-exists(red-text) => true

@overload #mixin_exists($name)

    @param name [Sass::Script::Value::String] The name of the mixin to
      check.

@return [Sass::Script::Value::Bool] Whether the mixin is defined.

    # File lib/sass/script/functions.rb, line 2307
    def mixin_exists(name)
      assert_type name, :String, :name
      bool(environment.mixin(name.value))
    end

nth(list, n) click to toggle source

Gets the nth item in a list.

Note that unlike some languages, the first item in a Sass list is number 1, the second number 2, and so forth.

This can return the nth pair in a map as well.

Negative index values address elements in reverse order, starting with the last element in the list.

@example

    nth(10px 20px 30px, 1) => 10px
    nth((Helvetica, Arial, sans-serif), 3) => sans-serif
    nth((width: 10px, length: 20px), 2) => length, 20px

@overload nth($list, $n)

    @param $list [Sass::Script::Value::Base]
    @param $n [Sass::Script::Value::Number] The index of the item to get.
      Negative indices count from the end of the list.

@return [Sass::Script::Value::Base] @raise [ArgumentError] if `$n` isn't an integer between 1 and the length

    of %x`$list`

    # File lib/sass/script/functions.rb, line 1866
    def nth(list, n)
      assert_type n, :Number, :n
      Sass::Script::Value::List.assert_valid_index(list, n)

      index = n.to_i > 0 ? n.to_i - 1 : n.to_i
      list.to_a[index]
    end

opacify(color, amount) click to toggle source

Makes a color more opaque. Takes a color and a number between 0 and 1, and returns a color with the opacity increased by that amount.

@see transparentize @example

    opacify(rgba(0, 0, 0, 0.5), 0.1) => rgba(0, 0, 0, 0.6)
    opacify(rgba(0, 0, 17, 0.8), 0.2) => #001

@overload opacify($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to increase the
      opacity by, between 0 and 1

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 916
    def opacify(color, amount)
      _adjust(color, amount, :alpha, 0..1, :+)
    end

Also aliased as: fade_in
opacity(color) click to toggle source

Returns the alpha component (opacity) of a color. This is 1 unless otherwise specified.

@overload opacity($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The alpha component, between 0 and 1 @raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 893
    def opacity(color)
      if color.is_a?(Sass::Script::Value::Number)
        return identifier("opacity(#{color})")
      end
      assert_type color, :Color, :color
      number(color.alpha)
    end

percentage(number) click to toggle source

Converts a unitless number to a percentage.

@example

    percentage(0.2) => 20%
    percentage(100px / 50px) => 200%

@overload percentage($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$number` isn't a unitless number

    # File lib/sass/script/functions.rb, line 1701
    def percentage(number)
      unless number.is_a?(Sass::Script::Value::Number) && number.unitless?
        raise ArgumentError.new("$number: #{number.inspect} is not a unitless number")
      end
      number(number.value * 100, '%')
    end

quote(string) click to toggle source

Add quotes to a string if the string isn't quoted, or returns the same string if it is.

@see unquote @example

    quote("foo") => "foo"
    quote(foo) => "foo"

@overload quote($string)

    @param $string [Sass::Script::Value::String]

@return [Sass::Script::Value::String] @raise [ArgumentError] if `$string` isn't a string

    # File lib/sass/script/functions.rb, line 1434
    def quote(string)
      assert_type string, :String, :string
      if string.type != :string
        quoted_string(string.value)
      else
        string
      end
    end

random(limit = nil) click to toggle source

@overload random()

    Return a decimal between 0 and 1, inclusive of 0 but not 1.
    @return [Sass::Script::Value::Number] A decimal value.

@overload random($limit)

    Return an integer between 1 and `$limit`, inclusive of both 1 and `$limit`.
    @param $limit [Sass::Script::Value::Number] The maximum of the random integer to be
      returned, a positive integer.
    @return [Sass::Script::Value::Number] An integer.
    @raise [ArgumentError] if the `$limit` is not 1 or greater

    # File lib/sass/script/functions.rb, line 2333
    def random(limit = nil)
      generator = Sass::Script::Functions.random_number_generator
      if limit
        assert_integer limit, "limit"
        if limit.to_i < 1
          raise ArgumentError.new("$limit #{limit} must be greater than or equal to 1")
        end
        number(1 + generator.rand(limit.to_i))
      else
        number(generator.rand)
      end
    end

red(color) click to toggle source

Gets the red component of a color. Calculated from HSL where necessary via [this algorithm].

[hsl-to-rgb]: www.w3.org/TR/css3-color/#hsl-color

@overload red($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The red component, between 0 and 255

    inclusive

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 768
    def red(color)
      assert_type color, :Color, :color
      number(color.red)
    end

rgb(red, green, blue) click to toggle source

Creates a {Sass::Script::Value::Color Color} object from red, green, and blue values.

@see rgba @overload rgb($red, $green, $blue)

    @param $red [Sass::Script::Value::Number] The amount of red in the color.
      Must be between 0 and 255 inclusive, or between `0%` and `100%`
      inclusive
    @param $green [Sass::Script::Value::Number] The amount of green in the
      color. Must be between 0 and 255 inclusive, or between `0%` and `100%`
      inclusive
    @param $blue [Sass::Script::Value::Number] The amount of blue in the
      color. Must be between 0 and 255 inclusive, or between `0%` and `100%`
      inclusive

@return [Sass::Script::Value::Color] @raise [ArgumentError] if any parameter is the wrong type or out of bounds

    # File lib/sass/script/functions.rb, line 626
    def rgb(red, green, blue)
      assert_type red, :Number, :red
      assert_type green, :Number, :green
      assert_type blue, :Number, :blue

      color_attrs = [[red, :red], [green, :green], [blue, :blue]].map do |(c, name)|
        if c.is_unit?("%")
          c.value * 255 / 100.0
        elsif c.unitless?
          c.value
        else
          raise ArgumentError.new("Expected #{c} to be unitless or have a unit of % but got #{c}")
        end
      end

      # Don't store the string representation for function-created colors, both
      # because it's not very useful and because some functions aren't supported
      # on older browsers.
      Sass::Script::Value::Color.new(color_attrs)
    end

rgba(*args) click to toggle source

Creates a {Sass::Script::Value::Color Color} from red, green, blue, and alpha values. @see rgb

@overload rgba($red, $green, $blue, $alpha)

    @param $red [Sass::Script::Value::Number] The amount of red in the
      color. Must be between 0 and 255 inclusive or 0% and 100% inclusive
    @param $green [Sass::Script::Value::Number] The amount of green in the
      color. Must be between 0 and 255 inclusive or 0% and 100% inclusive
    @param $blue [Sass::Script::Value::Number] The amount of blue in the
      color. Must be between 0 and 255 inclusive or 0% and 100% inclusive
    @param $alpha [Sass::Script::Value::Number] The opacity of the color.
      Must be between 0 and 1 inclusive
    @return [Sass::Script::Value::Color]
    @raise [ArgumentError] if any parameter is the wrong type or out of
      bounds

@overload rgba($color, $alpha)

    Sets the opacity of an existing color.

    @example
      rgba(#102030, 0.5) => rgba(16, 32, 48, 0.5)
      rgba(blue, 0.2)    => rgba(0, 0, 255, 0.2)

    @param $color [Sass::Script::Value::Color] The color whose opacity will
      be changed.
    @param $alpha [Sass::Script::Value::Number] The new opacity of the
      color. Must be between 0 and 1 inclusive
    @return [Sass::Script::Value::Color]
    @raise [ArgumentError] if `$alpha` is out of bounds or either parameter
      is the wrong type

    # File lib/sass/script/functions.rb, line 679
    def rgba(*args)
      case args.size
      when 2
        color, alpha = args

        assert_type color, :Color, :color
        assert_type alpha, :Number, :alpha
        check_alpha_unit alpha, 'rgba'

        color.with(:alpha => alpha.value)
      when 4
        red, green, blue, alpha = args
        rgba(rgb(red, green, blue), alpha)
      else
        raise ArgumentError.new("wrong number of arguments (#{args.size} for 4)")
      end
    end

round(number) click to toggle source

Rounds a number to the nearest whole number.

@example

    round(10.4px) => 10px
    round(10.6px) => 11px

@overload round($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1718
    def round(number)
      numeric_transformation(number) {|n| n.round}
    end

saturate(color, amount = nil) click to toggle source

Makes a color more saturated. Takes a color and a number between 0% and 100%, and returns a color with the saturation increased by that amount.

@see desaturate @example

    saturate(hsl(120, 30%, 90%), 20%) => hsl(120, 50%, 90%)
    saturate(#855, 20%) => #9e3f3f

@overload saturate($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to increase the
      saturation by, between `0%` and `100%`

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 998
    def saturate(color, amount = nil)
      # Support the filter effects definition of saturate.
      # https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html
      return identifier("saturate(#{color})") if amount.nil?
      _adjust(color, amount, :saturation, 0..100, :+, "%")
    end

saturation(color) click to toggle source

Returns the saturation component of a color. See [the CSS3 HSL specification]. Calculated from RGB where necessary via [this algorithm].

[hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV [rgb-to-hsl]: en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV

@overload saturation($color)

    @param $color [Sass::Script::Value::Color]

@return [Sass::Script::Value::Number] The saturation component, between 0%

    and 100%

@raise [ArgumentError] if `$color` isn't a color

    # File lib/sass/script/functions.rb, line 836
    def saturation(color)
      assert_type color, :Color, :color
      number(color.saturation, "%")
    end

scale_color(color, kwargs) click to toggle source

Fluidly scales one or more properties of a color. Unlike {#adjust_color adjust-color}, which changes a color's properties by fixed amounts, {#scale_color scale-color} fluidly changes them based on how high or low they already are. That means that lightening an already-light color with {#scale_color scale-color} won't change the lightness much, but lightening a dark color by the same amount will change it more dramatically. This has the benefit of making `scale-color($color, …)` have a similar effect regardless of what `$color` is.

For example, the lightness of a color can be anywhere between `0%` and `100%`. If `scale-color($color, $lightness: 40%)` is called, the resulting color's lightness will be 40% of the way between its original lightness and 100. If `scale-color($color, $lightness: -40%)` is called instead, the lightness will be 40% of the way between the original and 0.

This can change the red, green, blue, saturation, value, and alpha properties. The properties are specified as keyword arguments. All arguments should be percentages between `0%` and `100%`.

All properties are optional. You can't specify both RGB properties (`$red`, `$green`, `$blue`) and HSL properties (`$saturation`, `$value`) at the same time.

@example

    scale-color(hsl(120, 70%, 80%), $lightness: 50%) => hsl(120, 70%, 90%)
    scale-color(rgb(200, 150%, 170%), $green: -40%, $blue: 70%) => rgb(200, 90, 229)
    scale-color(hsl(200, 70%, 80%), $saturation: -90%, $alpha: -30%) => hsla(200, 7%, 80%, 0.7)

@comment

    rubocop:disable LineLength

@overload #scale_color($color, [$red], [$green], [$blue], [$saturation], [$lightness], [$alpha])

    @comment
      rubocop:disable LineLength
    @param $color [Sass::Script::Value::Color]
    @param $red [Sass::Script::Value::Number]
    @param $green [Sass::Script::Value::Number]
    @param $blue [Sass::Script::Value::Number]
    @param $saturation [Sass::Script::Value::Number]
    @param $lightness [Sass::Script::Value::Number]
    @param $alpha [Sass::Script::Value::Number]

@return [Sass::Script::Value::Color] @raise [ArgumentError] if any parameter is the wrong type or out-of

    bounds, or if RGB properties and HSL properties are adjusted at the
    same time

    # File lib/sass/script/functions.rb, line 1175
    def scale_color(color, kwargs)
      assert_type color, :Color, :color
      with = Sass::Util.map_hash(
          "red" => 255,
          "green" => 255,
          "blue" => 255,
          "saturation" => 100,
          "lightness" => 100,
          "alpha" => 1
        ) do |name, max|

        val = kwargs.delete(name)
        next unless val
        assert_type val, :Number, name
        assert_unit val, '%', name
        Sass::Util.check_range("$#{name}: Amount", -100..100, val, '%')

        current = color.send(name)
        scale = val.value / 100.0
        diff = scale > 0 ? max - current : current
        [name.to_sym, current + diff * scale]
      end

      unless kwargs.empty?
        name, val = kwargs.to_a.first
        raise ArgumentError.new("Unknown argument $#{name} (#{val})")
      end

      color.with(with)
    end

selector_append(*selectors) click to toggle source

Return a new selector with all selectors in `$selectors` appended one another as though they had been nested in the stylesheet as `$selector1 { &$selector2 { … } }`.

@example

    selector-append(".foo", ".bar", ".baz") => .foo.bar.baz
    selector-append(".a .foo", ".b .bar") => "a .foo.b .bar"
    selector-append(".foo", "-suffix") => ".foo-suffix"

@overload #selector_append($selectors…)

    @param $selectors [[Sass::Script::Value::String, Sass::Script::Value::List]]
      The selectors to append. At least one selector must be passed. Each of
      these can be either a string, a list of strings, or a list of lists of
      strings as returned by `&`.
    @return [Sass::Script::Value::List]
      A list of lists of strings representing the result of appending
      `$selectors`. This is in the same format as a selector returned by
      `&`.
    @raise [ArgumentError] if a selector could not be appended.

    # File lib/sass/script/functions.rb, line 2417
    def selector_append(*selectors)
      if selectors.empty?
        raise ArgumentError.new("$selectors: At least one selector must be passed")
      end

      selectors.map {|sel| parse_selector(sel, :selectors)}.inject do |parent, child|
        child.members.each do |seq|
          sseq = seq.members.first
          unless sseq.is_a?(Sass::Selector::SimpleSequence)
            raise ArgumentError.new("Can't append \"#{seq}\" to \"#{parent}\"")
          end

          base = sseq.base
          case base
          when Sass::Selector::Universal
            raise ArgumentError.new("Can't append \"#{seq}\" to \"#{parent}\"")
          when Sass::Selector::Element
            unless base.namespace.nil?
              raise ArgumentError.new("Can't append \"#{seq}\" to \"#{parent}\"")
            end
            sseq.members[0] = Sass::Selector::Parent.new(base.name)
          else
            sseq.members.unshift Sass::Selector::Parent.new
          end
        end
        child.resolve_parent_refs(parent)
      end.to_sass_script
    end

selector_extend(selector, extendee, extender) click to toggle source

Returns a new version of `$selector` with `$extendee` extended with `$extender`. This works just like the result of

    $selector { ... }
    $extender { @extend $extendee }

@example

    selector-extend(".a .b", ".b", ".foo .bar") => .a .b, .a .foo .bar, .foo .a .bar

@overload #selector_extend($selector, $extendee, $extender)

    @param $selector [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector within which `$extendee` is extended with
      `$extender`. This can be either a string, a list of strings,
      or a list of lists of strings as returned by `&`.
    @param $extendee [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector being extended. This can be either a string, a
      list of strings, or a list of lists of strings as returned
      by `&`.
    @param $extender [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector being injected into `$selector`. This can be
      either a string, a list of strings, or a list of lists of
      strings as returned by `&`.
    @return [Sass::Script::Value::List]
      A list of lists of strings representing the result of the
      extension. This is in the same format as a selector returned
      by `&`.
    @raise [ArgumentError] if the extension fails

    # File lib/sass/script/functions.rb, line 2474
    def selector_extend(selector, extendee, extender)
      selector = parse_selector(selector, :selector)
      extendee = parse_selector(extendee, :extendee)
      extender = parse_selector(extender, :extender)

      extends = Sass::Util::SubsetMap.new
      begin
        extender.populate_extends(extends, extendee)
        selector.do_extend(extends).to_sass_script
      rescue Sass::SyntaxError => e
        raise ArgumentError.new(e.to_s)
      end
    end

selector_nest(*selectors) click to toggle source

Return a new selector with all selectors in `$selectors` nested beneath one another as though they had been nested in the stylesheet as `$selector1 { $selector2 { … } }`.

Unlike most selector functions, `selector-nest` allows the parent selector `&` to be used in any selector but the first.

@example

    selector-nest(".foo", ".bar", ".baz") => .foo .bar .baz
    selector-nest(".a .foo", ".b .bar") => .a .foo .b .bar
    selector-nest(".foo", "&.bar") => .foo.bar

@overload #selector_nest($selectors…)

    @param $selectors [[Sass::Script::Value::String, Sass::Script::Value::List]]
      The selectors to nest. At least one selector must be passed. Each of
      these can be either a string, a list of strings, or a list of lists of
      strings as returned by `&`.
    @return [Sass::Script::Value::List]
      A list of lists of strings representing the result of nesting
      `$selectors`. This is in the same format as a selector returned by
      `&`.

    # File lib/sass/script/functions.rb, line 2387
    def selector_nest(*selectors)
      if selectors.empty?
        raise ArgumentError.new("$selectors: At least one selector must be passed")
      end

      parsed = [parse_selector(selectors.first, :selectors)]
      parsed += selectors[1..-1].map {|sel| parse_selector(sel, :selectors, !!:parse_parent_ref)}
      parsed.inject {|result, child| child.resolve_parent_refs(result)}.to_sass_script
    end

selector_parse(selector) click to toggle source

Parses a user-provided selector into a list of lists of strings as returned by `&`.

@example

    selector-parse(".foo .bar, .baz .bang") => ('.foo' '.bar', '.baz' '.bang')

@overload #selector_parse($selector)

    @param $selector [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector to parse. This can be either a string, a list of
      strings, or a list of lists of strings as returned by `&`.
    @return [Sass::Script::Value::List]
      A list of lists of strings representing `$selector`. This is
      in the same format as a selector returned by `&`.

    # File lib/sass/script/functions.rb, line 2361
    def selector_parse(selector)
      parse_selector(selector, :selector).to_sass_script
    end

selector_replace(selector, original, replacement) click to toggle source

Replaces all instances of `$original` with `$replacement` in `$selector`

This works by using `@extend` and throwing away the original selector. This means that it can be used to do very advanced replacements; see the examples below.

@example

    selector-replace(".foo .bar", ".bar", ".baz") => ".foo .baz"
    selector-replace(".foo.bar.baz", ".foo.baz", ".qux") => ".bar.qux"

@overload #selector_replace($selector, $original, $replacement)

    @param $selector [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector within which `$original` is replaced with
      `$replacement`. This can be either a string, a list of
      strings, or a list of lists of strings as returned by `&`.
    @param $original [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector being replaced. This can be either a string, a
      list of strings, or a list of lists of strings as returned
      by `&`.
    @param $replacement [Sass::Script::Value::String, Sass::Script::Value::List]
      The selector that `$original` is being replaced with. This
      can be either a string, a list of strings, or a list of
      lists of strings as returned by `&`.
    @return [Sass::Script::Value::List]
      A list of lists of strings representing the result of the
      extension. This is in the same format as a selector returned
      by `&`.
    @raise [ArgumentError] if the replacement fails

    # File lib/sass/script/functions.rb, line 2517
    def selector_replace(selector, original, replacement)
      selector = parse_selector(selector, :selector)
      original = parse_selector(original, :original)
      replacement = parse_selector(replacement, :replacement)

      extends = Sass::Util::SubsetMap.new
      begin
        replacement.populate_extends(extends, original)
        selector.do_extend(extends, [], !!:replace).to_sass_script
      rescue Sass::SyntaxError => e
        raise ArgumentError.new(e.to_s)
      end
    end

selector_unify(selector1, selector2) click to toggle source

Unifies two selectors into a single selector that matches only elements matched by both input selectors. Returns `null` if there is no such selector.

Like the selector unification done for `@extend`, this doesn't guarantee that the output selector will match all elements matched by both input selectors. For example, if `.a .b` is unified with `.x .y`, `.a .x .b.y, .x .a .b.y` will be returned, but `.a.x .b.y` will not. This avoids exponential output size while matching all elements that are likely to exist in practice.

@example

    selector-unify(".a", ".b") => .a.b
    selector-unify(".a .b", ".x .y") => .a .x .b.y, .x .a .b.y
    selector-unify(".a.b", ".b.c") => .a.b.c
    selector-unify("#a", "#b") => null

@overload #selector_unify($selector1, $selector2)

    @param $selector1 [Sass::Script::Value::String, Sass::Script::Value::List]
      The first selector to be unified. This can be either a
      string, a list of strings, or a list of lists of strings as
      returned by `&`.
    @param $selector2 [Sass::Script::Value::String, Sass::Script::Value::List]
      The second selector to be unified. This can be either a
      string, a list of strings, or a list of lists of strings as
      returned by `&`.
    @return [Sass::Script::Value::List, Sass::Script::Value::Null]
      A list of lists of strings representing the result of the
      unification, or null if no unification exists. This is in
      the same format as a selector returned by `&`.

    # File lib/sass/script/functions.rb, line 2563
    def selector_unify(selector1, selector2)
      selector1 = parse_selector(selector1, :selector1)
      selector2 = parse_selector(selector2, :selector2)
      return null unless (unified = selector1.unify(selector2))
      unified.to_sass_script
    end

set_nth(list, n, value) click to toggle source

Return a new list, based on the list provided, but with the nth element changed to the value given.

Note that unlike some languages, the first item in a Sass list is number 1, the second number 2, and so forth.

Negative index values address elements in reverse order, starting with the last element in the list.

@example

    set-nth($list: 10px 20px 30px, $n: 2, $value: -20px) => 10px -20px 30px

@overload set-nth($list, $n, $value)

    @param $list [Sass::Script::Value::Base] The list that will be copied, having the element
      at index `$n` changed.
    @param $n [Sass::Script::Value::Number] The index of the item to set.
      Negative indices count from the end of the list.
    @param $value [Sass::Script::Value::Base] The new value at index `$n`.

@return [Sass::Script::Value::List] @raise [ArgumentError] if `$n` isn't an integer between 1 and the length

    of %x`$list`

    # File lib/sass/script/functions.rb, line 1835
    def set_nth(list, n, value)
      assert_type n, :Number, :n
      Sass::Script::Value::List.assert_valid_index(list, n)
      index = n.to_i > 0 ? n.to_i - 1 : n.to_i
      new_list = list.to_a.dup
      new_list[index] = value
      Sass::Script::Value::List.new(new_list, list.separator)
    end

simple_selectors(selector) click to toggle source

Returns the [simple selectors](dev.w3.org/csswg/selectors4/#simple) that comprise the compound selector `$selector`.

Note that `$selector` **must be** a [compound selector](dev.w3.org/csswg/selectors4/#compound). That means it cannot contain commas or spaces. It also means that unlike other selector functions, this takes only strings, not lists.

@example

    simple-selectors(".foo.bar") => ".foo", ".bar"
    simple-selectors(".foo.bar.baz") => ".foo", ".bar", ".baz"

@overload #simple_selectors($selector)

    @param $selector [Sass::Script::Value::String]
      The compound selector whose simple selectors will be extracted.
    @return [Sass::Script::Value::List]
      A list of simple selectors in the compound selector.

    # File lib/sass/script/functions.rb, line 2590
    def simple_selectors(selector)
      selector = parse_compound_selector(selector, :selector)
      list(selector.members.map {|simple| unquoted_string(simple.to_s)}, :comma)
    end

str_index(string, substring) click to toggle source

Returns the index of the first occurrence of `$substring` in `$string`. If there is no such occurrence, returns `null`.

Note that unlike some languages, the first character in a Sass string is number 1, the second number 2, and so forth.

@example

    str-index(abcd, a)  => 1
    str-index(abcd, ab) => 1
    str-index(abcd, X)  => null
    str-index(abcd, c)  => 3

@overload #str_index($string, $substring)

    @param $string [Sass::Script::Value::String]
    @param $substring [Sass::Script::Value::String]

@return [Sass::Script::Value::Number, Sass::Script::Value::Null] @raise [ArgumentError] if any parameter is the wrong type

    # File lib/sass/script/functions.rb, line 1510
    def str_index(string, substring)
      assert_type string, :String, :string
      assert_type substring, :String, :substring
      index = string.value.index(substring.value)
      index ? number(index + 1) : null
    end

str_insert(original, insert, index) click to toggle source

Inserts `$insert` into `$string` at `$index`.

Note that unlike some languages, the first character in a Sass string is number 1, the second number 2, and so forth.

@example

    str-insert("abcd", "X", 1) => "Xabcd"
    str-insert("abcd", "X", 4) => "abcXd"
    str-insert("abcd", "X", 5) => "abcdX"

@overload #str_insert($string, $insert, $index)

    @param $string [Sass::Script::Value::String]
    @param $insert [Sass::Script::Value::String]
    @param $index [Sass::Script::Value::Number] The position at which
      `$insert` will be inserted. Negative indices count from the end of
      `$string`. An index that's outside the bounds of the string will insert
      `$insert` at the front or back of the string

@return [Sass::Script::Value::String] The result string. This will be

    quoted if and only if `$string` was quoted

@raise [ArgumentError] if any parameter is the wrong type

    # File lib/sass/script/functions.rb, line 1478
    def str_insert(original, insert, index)
      assert_type original, :String, :string
      assert_type insert, :String, :insert
      assert_integer index, :index
      assert_unit index, nil, :index
      insertion_point = if index.to_i > 0
                          [index.to_i - 1, original.value.size].min
                        else
                          [index.to_i, -original.value.size - 1].max
                        end
      result = original.value.dup.insert(insertion_point, insert.value)
      Sass::Script::Value::String.new(result, original.type)
    end

str_length(string) click to toggle source

Returns the number of characters in a string.

@example

    str-length("foo") => 3

@overload #str_length($string)

    @param $string [Sass::Script::Value::String]

@return [Sass::Script::Value::Number] @raise [ArgumentError] if `$string` isn't a string

    # File lib/sass/script/functions.rb, line 1452
    def str_length(string)
      assert_type string, :String, :string
      number(string.value.size)
    end

str_slice(string, start_at, end_at = nil) click to toggle source

Extracts a substring from `$string`. The substring will begin at index `$start-at` and ends at index `$end-at`.

Note that unlike some languages, the first character in a Sass string is number 1, the second number 2, and so forth.

@example

    str-slice("abcd", 2, 3)   => "bc"
    str-slice("abcd", 2)      => "bcd"
    str-slice("abcd", -3, -2) => "bc"
    str-slice("abcd", 2, -2)  => "bc"

@overload #str_slice($string, $start-at, $end-at: -1)

    @param $start-at [Sass::Script::Value::Number] The index of the first
      character of the substring. If this is negative, it counts from the end
      of `$string`
    @param $end-before [Sass::Script::Value::Number] The index of the last
      character of the substring. If this is negative, it counts from the end
      of `$string`. Defaults to -1
    @return [Sass::Script::Value::String] The substring. This will be quoted
      if and only if `$string` was quoted

@raise [ArgumentError] if any parameter is the wrong type

    # File lib/sass/script/functions.rb, line 1540
    def str_slice(string, start_at, end_at = nil)
      assert_type string, :String, :string
      assert_unit start_at, nil, "start-at"

      end_at = number(-1) if end_at.nil?
      assert_unit end_at, nil, "end-at"

      return Sass::Script::Value::String.new("", string.type) if end_at.value == 0
      s = start_at.value > 0 ? start_at.value - 1 : start_at.value
      e = end_at.value > 0 ? end_at.value - 1 : end_at.value
      s = string.value.length + s if s < 0
      s = 0 if s < 0
      e = string.value.length + e if e < 0
      e = 0 if s < 0
      extracted = string.value.slice(s..e)
      Sass::Script::Value::String.new(extracted || "", string.type)
    end

to_lower_case(string) click to toggle source

Convert a string to lower case,

@example

    to-lower-case(ABCD) => abcd

@overload #to_lower_case($string)

    @param $string [Sass::Script::Value::String]

@return [Sass::Script::Value::String] @raise [ArgumentError] if `$string` isn't a string

    # File lib/sass/script/functions.rb, line 1584
    def to_lower_case(string)
      assert_type string, :String, :string
      Sass::Script::Value::String.new(string.value.downcase, string.type)
    end

to_upper_case(string) click to toggle source

Converts a string to upper case.

@example

    to-upper-case(abcd) => ABCD

@overload #to_upper_case($string)

    @param $string [Sass::Script::Value::String]

@return [Sass::Script::Value::String] @raise [ArgumentError] if `$string` isn't a string

    # File lib/sass/script/functions.rb, line 1569
    def to_upper_case(string)
      assert_type string, :String, :string
      Sass::Script::Value::String.new(string.value.upcase, string.type)
    end

transparentize(color, amount) click to toggle source

Makes a color more transparent. Takes a color and a number between 0 and 1, and returns a color with the opacity decreased by that amount.

@see opacify @example

    transparentize(rgba(0, 0, 0, 0.5), 0.1) => rgba(0, 0, 0, 0.4)
    transparentize(rgba(0, 0, 0, 0.8), 0.2) => rgba(0, 0, 0, 0.6)

@overload transparentize($color, $amount)

    @param $color [Sass::Script::Value::Color]
    @param $amount [Sass::Script::Value::Number] The amount to decrease the
      opacity by, between 0 and 1

@return [Sass::Script::Value::Color] @raise [ArgumentError] if `$amount` is out of bounds, or either parameter

    is the wrong type

    # File lib/sass/script/functions.rb, line 938
    def transparentize(color, amount)
      _adjust(color, amount, :alpha, 0..1, :-)
    end

Also aliased as: fade_out
type_of(value) click to toggle source

Returns the type of a value.

@example

    type-of(100px)  => number
    type-of(asdf)   => string
    type-of("asdf") => string
    type-of(true)   => bool
    type-of(#fff)   => color
    type-of(blue)   => color

@overload #type_of($value)

    @param $value [Sass::Script::Value::Base] The value to inspect

@return [Sass::Script::Value::String] The unquoted string name of the

    value's type

    # File lib/sass/script/functions.rb, line 1603
    def type_of(value)
      identifier(value.class.name.gsub(/Sass::Script::Value::/, '').downcase)
    end

unique_id() click to toggle source

Returns a unique CSS identifier. The identifier is returned as an unquoted string. The identifier returned is only guaranteed to be unique within the scope of a single Sass run.

@overload #unique_id() @return [Sass::Script::Value::String]

    # File lib/sass/script/functions.rb, line 2166
    def unique_id
      generator = Sass::Script::Functions.random_number_generator
      Thread.current[:sass_last_unique_id] ||= generator.rand(36**8)
      # avoid the temptation of trying to guess the next unique value.
      value = (Thread.current[:sass_last_unique_id] += (generator.rand(10) + 1))
      # the u makes this a legal identifier if it would otherwise start with a number.
      identifier("u" + value.to_s(36).rjust(8, '0'))
    end

unit(number) click to toggle source

Returns the unit(s) associated with a number. Complex units are sorted in alphabetical order by numerator and denominator.

@example

    unit(100) => ""
    unit(100px) => "px"
    unit(3em) => "em"
    unit(10px * 5em) => "em*px"
    unit(10px * 5em / 30cm / 1rem) => "em*px/cm*rem"

@overload unit($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::String] The unit(s) of the number, as a

    quoted string

@raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1653
    def unit(number)
      assert_type number, :Number, :number
      quoted_string(number.unit_str)
    end

unitless(number) click to toggle source

Returns whether a number has units.

@example

    unitless(100) => true
    unitless(100px) => false

@overload unitless($number)

    @param $number [Sass::Script::Value::Number]

@return [Sass::Script::Value::Bool] @raise [ArgumentError] if `$number` isn't a number

    # File lib/sass/script/functions.rb, line 1668
    def unitless(number)
      assert_type number, :Number, :number
      bool(number.unitless?)
    end

unquote(string) click to toggle source

Removes quotes from a string. If the string is already unquoted, this will return it unmodified.

@see quote @example

    unquote("foo") => foo
    unquote(foo) => foo

@overload unquote($string)

    @param $string [Sass::Script::Value::String]

@return [Sass::Script::Value::String] @raise [ArgumentError] if `$string` isn't a string

    # File lib/sass/script/functions.rb, line 1399
        def unquote(string)
          unless string.is_a?(Sass::Script::Value::String)
            # Don't warn multiple times for the same source line.
            # rubocop:disable GlobalVars
            $_sass_warned_for_unquote ||= Set.new
            frame = environment.stack.frames.last
            key = [frame.filename, frame.line] if frame
            return string if frame && $_sass_warned_for_unquote.include?(key)
            $_sass_warned_for_unquote << key if frame
            # rubocop:enable GlobalVars

            Sass::Util.sass_warn("DEPRECATION WARNING: Passing #{string.to_sass}, a non-string value, to unquote()
    will be an error in future versions of Sass.
    #{environment.stack.to_s.gsub(/^/, ' ' * 8)}
    ".strip)
            return string
          end

          return string if string.type == :identifier
          identifier(string.value)
        end

variable_exists(name) click to toggle source

Check whether a variable with the given name exists in the current scope or in the global scope.

@example

    $a-false-value: false;
    variable-exists(a-false-value) => true

    variable-exists(nonexistent) => false

@overload #variable_exists($name)

    @param $name [Sass::Script::Value::String] The name of the variable to
      check. The name should not include the `$`.

@return [Sass::Script::Value::Bool] Whether the variable is defined in

    the current scope.

    # File lib/sass/script/functions.rb, line 2246
    def variable_exists(name)
      assert_type name, :String, :name
      bool(environment.caller.var(name.value))
    end

zip(*lists) click to toggle source

Combines several lists into a single multidimensional list. The nth value of the resulting list is a space separated list of the source lists' nth values.

The length of the resulting list is the length of the shortest list.

@example

    zip(1px 1px 3px, solid dashed solid, red green blue)
    => 1px solid red, 1px dashed green, 3px solid blue

@overload zip($lists…)

    @param $lists [[Sass::Script::Value::Base]]

@return [Sass::Script::Value::List]

    # File lib/sass/script/functions.rb, line 1956
    def zip(*lists)
      length = nil
      values = []
      lists.each do |list|
        array = list.to_a
        values << array.dup
        length = length.nil? ? array.length : [length, array.length].min
      end
      values.each do |value|
        value.slice!(length)
      end
      new_list_value = values.first.zip(*values[1..-1])
      list(new_list_value.map {|list| list(list, :space)}, :comma)
    end

### Private Instance Methods

_adjust(color, amount, attr, range, op, units = "") click to toggle source

@comment

    rubocop:disable ParameterLists

    # File lib/sass/script/functions.rb, line 2636
    def _adjust(color, amount, attr, range, op, units = "")
      # rubocop:enable ParameterLists
      assert_type color, :Color, :color
      assert_type amount, :Number, :amount
      Sass::Util.check_range('Amount', range, amount, units)

      color.with(attr => color.send(attr).send(op, amount.value))
    end

check_alpha_unit(alpha, function) click to toggle source

    # File lib/sass/script/functions.rb, line 2645
        def check_alpha_unit(alpha, function)
          return if alpha.unitless?

          if alpha.is_unit?("%")
            Sass::Util.sass_warn("DEPRECATION WARNING: Passing a percentage as the alpha value to #{function}() will be
    interpreted differently in future versions of Sass. For now, use #{alpha.value} instead.
    ")
          else
            Sass::Util.sass_warn("DEPRECATION WARNING: Passing a number with units as the alpha value to #{function}() is
    deprecated and will be an error in future versions of Sass. Use #{alpha.value} instead.
    ")
          end
        end

numeric_transformation(value) { |value| ... } click to toggle source

This method implements the pattern of transforming a numeric value into another numeric value with the same units. It yields a number to a block to perform the operation and return a number

    # File lib/sass/script/functions.rb, line 2628
    def numeric_transformation(value)
      assert_type value, :Number, :value
      Sass::Script::Value::Number.new(
        yield(value.value), value.numerator_units, value.denominator_units)
    end