Module Sass::Script::Functions
In: lib/sass/script/functions.rb

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

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

and it will call {Sass::Script::Functions#hsl}.

The following functions are provided:

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

## RGB Functions

\{rgb rgb($red, $green, $blue)} : Converts an `rgb(red, green, blue)` triplet into a color.

\{rgba rgba($red, $green, $blue, $alpha)} : Converts an `rgba(red, green, blue, alpha)` quadruplet into a color.

\{rgba rgba($color, $alpha)} : Adds an alpha layer to any color value.

\{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($color-1, $color-2, \[$weight\])} : Mixes two colors together.

## HSL Functions

\{hsl hsl($hue, $saturation, $lightness)} : Converts an `hsl(hue, saturation, lightness)` triplet into a color.

\{hsla hsla($hue, $saturation, $lightness, $alpha)} : Converts an `hsla(hue, saturation, lightness, alpha)` quadruplet into a color.

\{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)} : Add or change an alpha layer for any color value.

\{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, \[$red\], \[$green\], \[$blue\], \[$hue\], \[$saturation\], \[$lightness\], \[$alpha\])} : Increase or decrease any of the components of a color.

\{scale_color scale-color($color, \[$red\], \[$green\], \[$blue\], \[$saturation\], \[$lightness\], \[$alpha\])} : Fluidly scale one or more components 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 the quotes from a string.

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

## Number Functions

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

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

\{ceil ceil($value)} : Rounds a number up to the nearest whole number.

\{floor floor($value)} : Rounds a number down to the nearest whole number.

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

\{min min($x1, $x2, …)\} : Finds the minimum of several values.

\{max max($x1, $x2, …)\} : Finds the maximum of several values.

## List Functions {list-functions}

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

\{nth nth($list, $n)} : Returns a specific 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.

## Introspection Functions

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

\{unit unit($number)} : Returns the units associated with a number.

\{unitless unitless($number)} : Returns whether a number has units or not.

\{comparable comparable($number-1, $number-2)} : Returns whether two numbers can be added or compared.

## Miscellaneous Functions

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

## 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::String.new(string.value.reverse)
      end
      declare :reverse, :args => [: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 {Sass::Script::Literal} objects. Literal objects are also expected to be returned. This means that Ruby values must be unwrapped and wrapped.

Most Literal objects support the {Sass::Script::Literal#value value} accessor for getting their Ruby values. Color objects, though, must be accessed using {Sass::Script::Color#rgb rgb}, {Sass::Script::Color#red red}, {Sass::Script::Color#blue green}, or {Sass::Script::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 {Literal} objects within functions, be aware that it‘s not safe to call {Literal#to_s to_s} (or other methods that use the string representation) on those objects without first setting {Node#options= the options attribute}.

Methods

abs   adjust_color   adjust_hue   alpha   append   blue   ceil   change_color   comparable   complement   darken   declare   desaturate   fade_in   fade_out   floor   grayscale   green   hsl   hsla   hue   ie_hex_str   if   index   invert   join   length   lighten   lightness   max   min   mix   nth   opacify   opacity   percentage   quote   red   rgb   rgba   round   saturate   saturation   scale_color   signature   transparentize   type_of   unit   unitless   unquote   zip  

Classes and Modules

Class Sass::Script::Functions::EvaluationContext

Constants

Signature = Struct.new(:args, :var_args, :var_kwargs)   A class representing a Sass function signature.

@attr args [Array<Symbol>] The names of the arguments to the function. @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.

External Aliases

public_method_defined? -> callable?
  Returns whether user function with a given name exists.

@param function_name [String] @return [Boolean]

Public Class methods

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.

@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 {Sass::Script::Literal}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.

@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

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 [Number] The number of unnamed arguments the function was passed. @param kwarg_arity [Number] 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}.

Public Instance methods

Finds the absolute value of a number.

@example

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

@param value [Number] The number @return [Number] The absolute value @raise [ArgumentError] if `value` isn‘t a number

Adjusts 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.

`$red`, `$green`, and `$blue` properties should be between 0 and 255. `$saturation` and `$lightness` should be between 0% and 100%. `$alpha` should be between 0 and 1.

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)

@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param hue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [ArgumentError] if `color` is not a color,

  if any keyword argument is not a number,
  if any keyword argument is not in the legal range,
  if an unexpected keyword argument is given,
  or if both HSL and RGB properties are given.

Changes the hue of a color while retaining the lightness and saturation. Takes a color and a number of degrees (usually between -360deg and 360deg), and returns a color with the hue rotated by that value.

@example

  adjust-hue(hsl(120, 30%, 90%), 60deg) => hsl(180, 30%, 90%)
  adjust-hue(hsl(120, 30%, 90%), 060deg) => hsl(60, 30%, 90%)
  adjust-hue(#811, 45deg) => #886a11

@param color [Color] @param amount [Number] @return [Color] @raise [ArgumentError] If `color` isn‘t a color, or `number` isn‘t a number

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.

@overload def alpha(color) @param color [Color] @return [Number] @see opacify @see transparentize @raise [ArgumentError] If `color` isn‘t a color

Appends a single value onto the end of a list.

Unless the `$separator` argument is passed, if the list has 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 [Literal] The list to add the value to
  @param val [Literal] The value to add to the end of the list
  @param separator [String] How the list separator (comma or space) should be determined.
    If this is `comma` or `space`, that is always the separator;
    if this is `auto` (the default), the separator is the same as that used by the list.

Returns the blue component of a color.

@param color [Color] @return [Number] @raise [ArgumentError] If `color` isn‘t a color

Rounds a number up to the nearest whole number.

@example

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

@param value [Number] The number @return [Number] The rounded number @raise [ArgumentError] if `value` isn‘t a number

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.

`$red`, `$green`, and `$blue` properties should be between 0 and 255. `$saturation` and `$lightness` should be between 0% and 100%. `$alpha` should be between 0 and 1.

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)

@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param hue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [ArgumentError] if `color` is not a color,

  if any keyword argument is not a number,
  if any keyword argument is not in the legal range,
  if an unexpected keyword argument is given,
  or if both HSL and RGB properties are given.

Returns true if two numbers are similar enough to be added, subtracted, or compared.

@example

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

@param number_1 [Number] @param number_2 [Number] @return [Bool] indicating if the numbers can be compared. @raise [ArgumentError] if `number_1` or `number_2` aren‘t numbers

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

@param color [Color] @return [Color] @raise [ArgumentError] if `color` isn‘t a color @see adjust_hue adjust-hue

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

@example

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

@param color [Color] @param amount [Number] @return [Color] @see lighten @raise [ArgumentError] If `color` isn‘t a color,

  or `number` isn't a number between 0% and 100%

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

@example

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

@param color [Color] @param amount [Number] @return [Color] @see saturate @raise [ArgumentError] If `color` isn‘t a color,

  or `number` isn't a number between 0% and 100%
fade_in(color, amount)

Alias for opacify

fade_out(color, amount)

Alias for transparentize

Rounds down to the nearest whole number.

@example

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

@param value [Number] The number @return [Number] The rounded number @raise [ArgumentError] if `value` isn‘t a number

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

@param color [Color] @return [Color] @raise [ArgumentError] if `color` isn‘t a color @see desaturate

Returns the green component of a color.

@param color [Color] @return [Number] @raise [ArgumentError] If `color` isn‘t a color

Creates a {Color} object from hue, saturation, and lightness. Uses the algorithm from the [CSS3 spec](www.w3.org/TR/css3-color/#hsl-color).

@param hue [Number] The hue of the color.

  Should be between 0 and 360 degrees, inclusive

@param saturation [Number] The saturation of the color.

  Must be between `0%` and `100%`, inclusive

@param lightness [Number] The lightness of the color.

  Must be between `0%` and `100%`, inclusive

@return [Color] The resulting color @see hsla @raise [ArgumentError] if `saturation` or `lightness` are out of bounds

Creates a {Color} object from hue, saturation, and lightness, as well as an alpha channel indicating opacity. Uses the algorithm from the [CSS3 spec](www.w3.org/TR/css3-color/#hsl-color).

@param hue [Number] The hue of the color.

  Should be between 0 and 360 degrees, inclusive

@param saturation [Number] The saturation of the color.

  Must be between `0%` and `100%`, inclusive

@param lightness [Number] The lightness of the color.

  Must be between `0%` and `100%`, inclusive

@param alpha [Number] The opacity of the color.

  Must be between 0 and 1, inclusive

@return [Color] The resulting color @see hsl @raise [ArgumentError] if `saturation`, `lightness`, or `alpha` are out of bounds

Returns the hue component of a color.

See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

@param color [Color] @return [Number] between 0deg and 360deg @see adjust_hue @raise [ArgumentError] if `color` isn‘t a color

Returns an IE hex string for a color with an alpha channel suitable for passing to IE filters.

@example

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

@param color [Color] @return [String] @raise [ArgumentError] If `color` isn‘t a color

Returns one of two values based on the truth value of the first argument.

@example

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

@param condition [Bool] Whether the first or second value will be returned. @param if_true [Literal] The value that will be returned if `$condition` is true. @param if_false [Literal] The value that will be returned if `$condition` is false.

Returns the position of the given value within the given list. If not found, returns false.

@example

  index(1px solid red, solid) => 2
  index(1px solid red, dashed) => false

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

@param color [Color] @return [Color] @raise [ArgumentError] if `color` isn‘t a color

Joins together two lists into a new list.

Unless the `$separator` argument 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 the lists have only one item each, 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 [Literal] The first list to join
  @param list2 [Literal] The second list to join
  @param separator [String] How the list separator (comma or space) should be determined.
    If this is `comma` or `space`, that is always the separator;
    if this is `auto` (the default), the separator is determined as explained above.

Return the length of a list.

@example

  length(10px) => 1
  length(10px 20px 30px) => 3

@param list [Literal] The list @return [Number] The length

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

@example

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

@param color [Color] @param amount [Number] @return [Color] @see darken @raise [ArgumentError] If `color` isn‘t a color,

  or `number` isn't a number between 0% and 100%

Returns the hue component of a color.

See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

@param color [Color] @return [Number] between 0% and 100% @see lighten @see darken @raise [ArgumentError] if `color` isn‘t a color

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

@example

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

@return [Number] The maximum value @raise [ArgumentError] if any argument isn‘t a number, or if not all of

  the arguments have comparable units

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

@example

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

@param values [[Number]] The numbers @return [Number] The minimum value @raise [ArgumentError] if any argument isn‘t a number, or if not all of

  the arguments have comparable units

Mixes together two colors. 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 [Color]
  @param color2 [Color]
  @param weight [Number] between 0% and 100%
  @return [Color]
  @raise [ArgumentError] if `color1` or `color2` aren't colors,
    or `weight` isn't a number between 0% and 100%

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.

@example

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

@param list [Literal] The list @param n [Number] The index into the list @return [Literal] The nth item in the list @raise [ArgumentError] If `n` isn‘t an integer between 1 and the list‘s length.

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

@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

@param color [Color] @param amount [Number] @return [Color] @see transparentize @raise [ArgumentError] If `color` isn‘t a color,

  or `number` isn't a number between 0 and 1

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

@param color [Color] @return [Number] @see opacify @see transparentize @raise [ArgumentError] If `color` isn‘t a color

Converts a decimal number to a percentage.

@example

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

@param value [Number] The decimal number to convert to a percentage @return [Number] The percentage @raise [ArgumentError] If `value` isn‘t a unitless number

Add quotes to a string if the string isn‘t quoted, or returns the same string if it is.

@param string [String] @return [String] @raise [ArgumentError] if `string` isn‘t a string @see unquote @example

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

Returns the red component of a color.

@param color [Color] @return [Number] @raise [ArgumentError] If `color` isn‘t a color

Creates a {Color} object from red, green, and blue values.

@param red [Number]

  A number between 0 and 255 inclusive,
  or between 0% and 100% inclusive

@param green [Number]

  A number between 0 and 255 inclusive,
  or between 0% and 100% inclusive

@param blue [Number]

  A number between 0 and 255 inclusive,
  or between 0% and 100% inclusive

@see rgba @return [Color]

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

  Creates a {Color} object from red, green, and blue values,
  as well as an alpha channel indicating opacity.

  @param red [Number]
    A number between 0 and 255 inclusive
  @param green [Number]
    A number between 0 and 255 inclusive
  @param blue [Number]
    A number between 0 and 255 inclusive
  @param alpha [Number]
    A number between 0 and 1
  @return [Color]

@overload rgba(color, alpha)

  Sets the opacity of a color.

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

  @param color [Color]
  @param alpha [Number]
    A number between 0 and 1
  @return [Color]

Rounds a number to the nearest whole number.

@example

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

@param value [Number] The number @return [Number] The rounded number @raise [ArgumentError] if `value` isn‘t a number

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

@example

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

@overload saturate(color, amount)

  @param color [Color]
  @param amount [Number]
  @return [Color]
  @see #desaturate
  @raise [ArgumentError] If `color` isn't a color,
    or `number` isn't a number between 0% and 100%

Returns the saturation component of a color.

See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).

@param color [Color] @return [Number] between 0% and 100% @see saturate @see desaturate @raise [ArgumentError] if `color` isn‘t a color

Scales one or more properties of a color by a percentage value. 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)

@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [ArgumentError] if `color` is not a color,

  if any keyword argument is not a percentage between 0% and 100%,
  if an unexpected keyword argument is given,
  or if both HSL and RGB properties are given.

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

@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)

@param color [Color] @param amount [Number] @return [Color] @see opacify @raise [ArgumentError] If `color` isn‘t a color,

  or `number` isn't a number between 0 and 1

Inspects the type of the argument, returning it as an unquoted string.

@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

@param value [Literal] The object to inspect @return [String] The unquoted string name of the literal‘s type

Inspects the unit of the number, returning it as a quoted string. 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"

@param number [Literal] The number to inspect @return [String] The unit(s) of the number @raise [ArgumentError] if `number` isn‘t a number

Inspects the unit of the number, returning a boolean indicating if it is unitless.

@example

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

@param number [Literal] The number to inspect @return [Bool] Whether or not the number is unitless @raise [ArgumentError] if `number` isn‘t a number

Removes quotes from a string if the string is quoted, or returns the same string if it‘s not.

@param string [String] @return [String] @raise [ArgumentError] if `string` isn‘t a string @see quote @example

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

Combines several lists into a single comma separated list space separated lists.

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

[Validate]