Module: Sass::Script::Functions

Included in:
EvaluationContext
Defined in:
lib/sass/script/functions.rb

Overview

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

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

and it will call #hsl.

The following functions are provided:

Note: These functions are described in more detail below.

RGB Functions

rgb($red, $green, $blue) : Creates a Color from red, green, and blue values.

rgba($red, $green, $blue, $alpha) : Creates a Color from red, green, blue, and alpha values.

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

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

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

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

HSL Functions

hsl($hue, $saturation, $lightness) : Creates a Color from hue, saturation, and lightness values.

hsla($hue, $saturation, $lightness, $alpha) : Creates a Color from hue, saturation, lightness, and alpha values.

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

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

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

adjust-hue($color, $degrees) : Changes the hue of a color.

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

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

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

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

grayscale($color) : Converts a color to grayscale.

complement($color) : Returns the complement of a color.

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

Opacity Functions

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

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

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

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

Other Color Functions

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

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

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

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

String Functions

unquote($string) : Removes quotes from a string.

quote($string) : Adds quotes to a string.

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

str-insert($string, $insert, $index) : Inserts $insert into $string at $index.

str-index($string, $substring) : Returns the index of the first occurance of $substring in $string.

str-slice($string, $start-at, [$end-at]) : Extracts a substring from $string.

to-upper-case($string) : Converts a string to upper case.

to-lower-case($string) : Converts a string to lower case.

Number Functions

percentage($number) : Converts a unitless number to a percentage.

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

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

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

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

min($numbers...) : Finds the minimum of several numbers.

max($numbers...) : Finds the maximum of several numbers.

random([$limit]) : Returns a random number.

List Functions #list-functions

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

length($list) : Returns the length of a list.

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

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

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

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

zip($lists...) : Combines several lists into a single multidimensional list.

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

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

Map Functions #map-functions

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

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

map-remove($map, $keys...) : Returns a new map with keys removed.

map-keys($map) : Returns a list of all keys in a map.

map-values($map) : Returns a list of all values in a map.

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

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 sring, 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($selectors...) : Nests selector beneath one another like they would be nested in the stylesheet.

selector-append($selectors...) : Appends selectors to one another without spaces in between.

selector-extend($selector, $extendee, $extender) : Extends $extendee with $extender within $selector.

selector-replace($selector, $original, $replacement) : Replaces $original with $replacement within $selector.

selector-unify($selector1, $selector2) : Unifies two selectors to produce a selector that matches elements matched by both.

is-superselector($super, $sub) : Returns whether $super matches all the elements $sub does, and possibly more.

simple-selectors($selector) : Returns the simple selectors that comprise a compound selector.

selector-parse($selector) : Parses a selector into the format returned by &.

Introspection Functions

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

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

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

function-exists($name) : Returns whether a function with the given name exists.

mixin-exists($name) : Returns whether a mixin with the given name exists.

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

type-of($value) : Returns the type of a value.

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

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

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

call($name, $args...) : Dynamically calls a Sass function.

Miscellaneous Functions

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

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 Functions.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. Functions.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 accessor for getting their Ruby values. Color objects, though, must be accessed using rgb, red, green, or 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 Engine to render the code, using the options parameter to pass in data that 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 #to_s (or other methods that use the string representation) on those objects without first setting the #options attribute.

Defined Under Namespace

Classes: EvaluationContext, Signature

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.declare(method_name, args, options = {})

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.

Examples:

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

Parameters:

  • method_name (Symbol)

    The name of the method whose signature is being declared.

  • args (Array<Symbol>)

    The names of the arguments for the function signature.

  • options (Hash) (defaults to: {})

    a customizable set of options

Options Hash (options):

  • :var_args (Boolean) — default: false

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

  • :var_kwargs (Boolean) — default: 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 Values 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.



399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
# 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_generatorRandom

Get Sass's internal random number generator.

Returns:

  • (Random)


473
474
475
# File 'lib/sass/script/functions.rb', line 473

def self.random_number_generator
  @random_number_generator ||= Sass::Util::CrossPlatformRandom.new
end

.random_seed=(seed) ⇒ Integer

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.

Parameters:

  • seed (Integer)

Returns:

  • (Integer)

    The same seed.



466
467
468
# 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) ⇒ {Symbol => Object}?

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.

Parameters:

  • method_name (Symbol)

    The name of the Ruby function to be called.

  • arg_arity (Fixnum)

    The number of unnamed arguments the function was passed.

  • kwarg_arity (Fixnum)

    The number of keyword arguments the function was passed.

Returns:

  • ({Symbol => Object}, nil)

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



433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
# 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

Instance Method Details

#abs($number) ⇒ Sass::Script::Value::Number

Returns the absolute value of a number.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1745
1746
1747
# File 'lib/sass/script/functions.rb', line 1745

def abs(number)
  numeric_transformation(number) {|n| n.abs}
end

#adjust_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]) ⇒ Sass::Script::Value::Color

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.

Examples:

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)

Parameters:

Returns:

Raises:

  • (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



1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
# 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) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if either parameter is the wrong type



1040
1041
1042
1043
1044
# 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($color) ⇒ Sass::Script::Value::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 as a special case.

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



870
871
872
873
874
875
876
877
878
879
880
881
882
883
# 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: auto) ⇒ Sass::Script::Value::List

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.

Examples:

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

Parameters:

Returns:



1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
# File 'lib/sass/script/functions.rb', line 1913

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) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



800
801
802
803
# File 'lib/sass/script/functions.rb', line 800

def blue(color)
  assert_type color, :Color, :color
  number(color.blue)
end

#call($name, $args...)

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.

Examples:

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

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

Parameters:

  • $name (String)

    The name of the function to call.



2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
# File 'lib/sass/script/functions.rb', line 2175

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) ⇒ Sass::Script::Value::Number

Rounds a number up to the next whole number.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1717
1718
1719
# File 'lib/sass/script/functions.rb', line 1717

def ceil(number)
  numeric_transformation(number) {|n| n.ceil}
end

#change_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]) ⇒ Sass::Script::Value::Color

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.

Examples:

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)

Parameters:

Returns:

Raises:

  • (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



1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
# 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) ⇒ Sass::Script::Value::Bool

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if either parameter is the wrong type



1670
1671
1672
1673
1674
# File 'lib/sass/script/functions.rb', line 1670

def comparable(number1, number2)
  assert_type number1, :Number, :number1
  assert_type number2, :Number, :number2
  bool(number1.comparable_to?(number2))
end

#complement($color) ⇒ Sass::Script::Value::Color

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color

See Also:



1363
1364
1365
# File 'lib/sass/script/functions.rb', line 1363

def complement(color)
  adjust_hue color, number(180)
end

#counter($args...) ⇒ Sass::Script::Value::String

This function only exists as a workaround for IE7's content: counter bug. It works identically to any other plain-CSS function, except it avoids adding spaces between the argument commas.

Examples:

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

Returns:



2198
2199
2200
# File 'lib/sass/script/functions.rb', line 2198

def counter(*args)
  identifier("counter(#{args.map {|a| a.to_s(options)}.join(',')})")
end

#counters($args...) ⇒ Sass::Script::Value::String

This function only exists as a workaround for IE7's content: counter bug. It works identically to any other plain-CSS function, except it avoids adding spaces between the argument commas.

Examples:

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

Returns:



2212
2213
2214
# File 'lib/sass/script/functions.rb', line 2212

def counters(*args)
  identifier("counters(#{args.map {|a| a.to_s(options)}.join(',')})")
end

#darken($color, $amount) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



979
980
981
# File 'lib/sass/script/functions.rb', line 979

def darken(color, amount)
  _adjust(color, amount, :lightness, 0..100, :-, "%")
end

#desaturate($color, $amount) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



1021
1022
1023
# File 'lib/sass/script/functions.rb', line 1021

def desaturate(color, amount)
  _adjust(color, amount, :saturation, 0..100, :-, "%")
end

#feature_exists($feature) ⇒ Sass::Script::Value::Bool

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.

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $feature isn't a string



1618
1619
1620
1621
# File 'lib/sass/script/functions.rb', line 1618

def feature_exists(feature)
  assert_type feature, :String, :feature
  bool(Sass.has_feature?(feature.value))
end

#floor($number) ⇒ Sass::Script::Value::Number

Rounds a number down to the previous whole number.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1731
1732
1733
# File 'lib/sass/script/functions.rb', line 1731

def floor(number)
  numeric_transformation(number) {|n| n.floor}
end

#function_exists($name) ⇒ Sass::Script::Value::Bool

Check whether a function with the given name exists.

Examples:

function-exists(lighten) => true

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

Parameters:

Returns:



2272
2273
2274
2275
2276
2277
# File 'lib/sass/script/functions.rb', line 2272

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) ⇒ Sass::Script::Value::Bool

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

Examples:

$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 */ }
}

Parameters:

Returns:



2254
2255
2256
2257
# File 'lib/sass/script/functions.rb', line 2254

def global_variable_exists(name)
  assert_type name, :String, :name
  bool(environment.global_env.var(name.value))
end

#grayscale($color) ⇒ Sass::Script::Value::Color

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color

See Also:



1347
1348
1349
1350
1351
1352
# 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) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



784
785
786
787
# File 'lib/sass/script/functions.rb', line 784

def green(color)
  assert_type color, :Color, :color
  number(color.green)
end

#hsl($hue, $saturation, $lightness) ⇒ Sass::Script::Value::Color

Creates a Color from hue, saturation, and lightness values. Uses the algorithm from the CSS3 spec.

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $saturation or $lightness are out of bounds or any parameter is the wrong type

See Also:



715
716
717
# 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) ⇒ Sass::Script::Value::Color

Creates a Color from hue, saturation, lightness, and alpha values. Uses the algorithm from the CSS3 spec.

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $saturation, $lightness, or $alpha are out of bounds or any parameter is the wrong type

See Also:



739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
# 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) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



818
819
820
821
# 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) ⇒ Sass::Script::Value::String

Converts a color into the format understood by IE filters.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



1058
1059
1060
1061
1062
# 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) ⇒ Sass::Script::Value::Base

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.

Examples:

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

Parameters:

Returns:



2136
2137
2138
2139
2140
2141
2142
# File 'lib/sass/script/functions.rb', line 2136

def if(condition, if_true, if_false)
  if condition.to_bool
    perform(if_true)
  else
    perform(if_false)
  end
end

#index($list, $value) ⇒ Sass::Script::Value::Number, Sass::Script::Value::Null

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.

Examples:

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

Returns:



1974
1975
1976
1977
# File 'lib/sass/script/functions.rb', line 1974

def index(list, value)
  index = list.to_a.index {|e| e.eq(value).to_bool}
  index ? number(index + 1) : null
end

#inspect($value) ⇒ Sass::Script::Value::String

Return a string containing the value as its Sass representation.

Parameters:

Returns:



2304
2305
2306
# File 'lib/sass/script/functions.rb', line 2304

def inspect(value)
  unquoted_string(value.to_sass)
end

#invert($color) ⇒ Sass::Script::Value::Color

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
# 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($super, $sub) ⇒ Sass::Script::Value::Bool

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.

Examples:

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

Returns Whether $selector1 is a superselector of $selector2.

Parameters:

Returns:



2601
2602
2603
2604
2605
# File 'lib/sass/script/functions.rb', line 2601

def is_superselector(sup, sub)
  sup = parse_selector(sup, :super)
  sub = parse_selector(sub, :sub)
  bool(sup.superselector?(sub))
end

#join($list1, $list2, $separator: auto) ⇒ Sass::Script::Value::List

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.

Examples:

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

Parameters:

Returns:



1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
# File 'lib/sass/script/functions.rb', line 1880

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) ⇒ Sass::Script::Value::Map

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 $.

Examples:

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

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $args isn't a variable argument list



2117
2118
2119
2120
# File 'lib/sass/script/functions.rb', line 2117

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) ⇒ Sass::Script::Value::Number

Return the length of a list.

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

Examples:

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

Parameters:

Returns:



1795
1796
1797
# File 'lib/sass/script/functions.rb', line 1795

def length(list)
  number(list.to_a.size)
end

#lighten($color, $amount) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



960
961
962
# File 'lib/sass/script/functions.rb', line 960

def lighten(color, amount)
  _adjust(color, amount, :lightness, 0..100, :+, "%")
end

#lightness($color) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



854
855
856
857
# File 'lib/sass/script/functions.rb', line 854

def lightness(color)
  assert_type color, :Color, :color
  number(color.lightness, "%")
end

#list_separator($list) ⇒ Sass::Script::Value::String

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

Examples:

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

Parameters:

Returns:



1990
1991
1992
# File 'lib/sass/script/functions.rb', line 1990

def list_separator(list)
  identifier((list.separator || :space).to_s)
end

#map_get($map, $key) ⇒ Sass::Script::Value::Base

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

Examples:

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

Returns:

Raises:

  • (ArgumentError)

    if $map is not a map



2008
2009
2010
2011
# File 'lib/sass/script/functions.rb', line 2008

def map_get(map, key)
  assert_type map, :Map, :map
  map.to_h[key] || null
end

#map_has_key($map, $key) ⇒ Sass::Script::Value::Bool

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

Examples:

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

Returns:

Raises:

  • (ArgumentError)

    if $map is not a map



2097
2098
2099
2100
# File 'lib/sass/script/functions.rb', line 2097

def map_has_key(map, key)
  assert_type map, :Map, :map
  bool(map.to_h.has_key?(key))
end

#map_keys($map) ⇒ List

Returns a list of all keys in a map.

Examples:

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

Parameters:

  • $map (Map)

Returns:

  • (List)

    the list of keys, comma-separated

Raises:

  • (ArgumentError)

    if $map is not a map



2065
2066
2067
2068
# File 'lib/sass/script/functions.rb', line 2065

def map_keys(map)
  assert_type map, :Map, :map
  list(map.to_h.keys, :comma)
end

#map_merge($map1, $map2) ⇒ Sass::Script::Value::Map

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.

Examples:

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

Returns:

Raises:

  • (ArgumentError)

    if either parameter is not a map



2031
2032
2033
2034
2035
# File 'lib/sass/script/functions.rb', line 2031

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...) ⇒ Sass::Script::Value::Map

Returns a new map with keys removed.

Examples:

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)

Returns:

Raises:

  • (ArgumentError)

    if $map is not a map



2049
2050
2051
2052
2053
2054
# File 'lib/sass/script/functions.rb', line 2049

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) ⇒ List

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

Examples:

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

Parameters:

  • $map (Map)

Returns:

  • (List)

    the list of values, comma-separated

Raises:

  • (ArgumentError)

    if $map is not a map



2081
2082
2083
2084
# File 'lib/sass/script/functions.rb', line 2081

def map_values(map)
  assert_type map, :Map, :map
  list(map.to_h.values, :comma)
end

#max($numbers...) ⇒ Sass::Script::Value::Number

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if any argument isn't a number, or if not all of the arguments have comparable units



1778
1779
1780
1781
# File 'lib/sass/script/functions.rb', line 1778

def max(*values)
  values.each {|v| assert_type v, :Number}
  values.inject {|max, val| max.gt(val).to_bool ? max : val}
end

#min($numbers...) ⇒ Sass::Script::Value::Number

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if any argument isn't a number, or if not all of the arguments have comparable units



1761
1762
1763
1764
# File 'lib/sass/script/functions.rb', line 1761

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: 50%) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $weight is out of bounds or any parameter is the wrong type



1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
# 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) ⇒ Sass::Script::Value::Bool

Check whether a mixin with the given name exists.

Examples:

mixin-exists(nonexistent) => false

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

Parameters:

Returns:



2292
2293
2294
2295
# File 'lib/sass/script/functions.rb', line 2292

def mixin_exists(name)
  assert_type name, :String, :name
  bool(environment.mixin(name.value))
end

#nth($list, $n) ⇒ Sass::Script::Value::Base

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $n isn't an integer between 1 and the length of $list



1851
1852
1853
1854
1855
1856
1857
# File 'lib/sass/script/functions.rb', line 1851

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) ⇒ Sass::Script::Value::Color Also known as: fade_in

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



916
917
918
# File 'lib/sass/script/functions.rb', line 916

def opacify(color, amount)
  _adjust(color, amount, :alpha, 0..1, :+)
end

#opacity($color) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



893
894
895
896
897
898
899
# 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) ⇒ Sass::Script::Value::Number

Converts a unitless number to a percentage.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a unitless number



1686
1687
1688
1689
1690
1691
# File 'lib/sass/script/functions.rb', line 1686

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) ⇒ Sass::Script::Value::String

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $string isn't a string

See Also:



1419
1420
1421
1422
1423
1424
1425
1426
# File 'lib/sass/script/functions.rb', line 1419

def quote(string)
  assert_type string, :String, :string
  if string.type != :string
    quoted_string(string.value)
  else
    string
  end
end

#randomSass::Script::Value::Number #random($limit) ⇒ Sass::Script::Value::Number

Overloads:



2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
# File 'lib/sass/script/functions.rb', line 2318

def random(limit = nil)
  generator = Sass::Script::Functions.random_number_generator
  if limit
    assert_integer limit, "limit"
    if limit.value < 1
      raise ArgumentError.new("$limit #{limit} must be greater than or equal to 1")
    end
    number(1 + generator.rand(limit.value))
  else
    number(generator.rand)
  end
end

#red($color) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



768
769
770
771
# File 'lib/sass/script/functions.rb', line 768

def red(color)
  assert_type color, :Color, :color
  number(color.red)
end

#rgb($red, $green, $blue) ⇒ Sass::Script::Value::Color

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

Parameters:

  • $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

  • $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

  • $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

Returns:

Raises:

  • (ArgumentError)

    if any parameter is the wrong type or out of bounds

See Also:



626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
# 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($red, $green, $blue, $alpha) ⇒ Sass::Script::Value::Color #rgba($color, $alpha) ⇒ Sass::Script::Value::Color

Creates a Color from red, green, blue, and alpha values.

Overloads:

See Also:



679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
# 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) ⇒ Sass::Script::Value::Number

Rounds a number to the nearest whole number.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1703
1704
1705
# File 'lib/sass/script/functions.rb', line 1703

def round(number)
  numeric_transformation(number) {|n| n.round}
end

#saturate($color, $amount) ⇒ Sass::Script::Value::Color

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



998
999
1000
1001
1002
1003
# 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) ⇒ Sass::Script::Value::Number

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $color isn't a color



836
837
838
839
# File 'lib/sass/script/functions.rb', line 836

def saturation(color)
  assert_type color, :Color, :color
  number(color.saturation, "%")
end

#scale_color($color, [$red], [$green], [$blue], [$saturation], [$lightness], [$alpha]) ⇒ Sass::Script::Value::Color

Fluidly scales one or more properties of a color. Unlike adjust-color, which changes a color's properties by fixed amounts, 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 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.

Examples:

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)

Returns:

Raises:

  • (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



1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
# 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...) ⇒ Sass::Script::Value::List

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

Examples:

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

Returns A list of lists of strings representing the result of appending $selectors. This is in the same format as a selector returned by &.

Parameters:

Returns:

  • (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 &.

Raises:

  • (ArgumentError)

    if a selector could not be appended.



2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
# File 'lib/sass/script/functions.rb', line 2402

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) ⇒ Sass::Script::Value::List

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

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

Examples:

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

Returns A list of lists of strings representing the result of the extension. This is in the same format as a selector returned by &.

Parameters:

Returns:

  • (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 &.

Raises:

  • (ArgumentError)

    if the extension fails



2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
# File 'lib/sass/script/functions.rb', line 2459

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...) ⇒ Sass::Script::Value::List

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.

Examples:

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

Returns A list of lists of strings representing the result of nesting $selectors. This is in the same format as a selector returned by &.

Parameters:

Returns:

  • (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 &.



2372
2373
2374
2375
2376
2377
2378
2379
2380
# File 'lib/sass/script/functions.rb', line 2372

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) ⇒ Sass::Script::Value::List

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

Examples:

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

Returns A list of lists of strings representing $selector. This is in the same format as a selector returned by &.

Parameters:

Returns:

  • (Sass::Script::Value::List)

    A list of lists of strings representing $selector. This is in the same format as a selector returned by &.



2346
2347
2348
# File 'lib/sass/script/functions.rb', line 2346

def selector_parse(selector)
  parse_selector(selector, :selector).to_sass_script
end

#selector_replace($selector, $original, $replacement) ⇒ Sass::Script::Value::List

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.

Examples:

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

Returns A list of lists of strings representing the result of the extension. This is in the same format as a selector returned by &.

Parameters:

Returns:

  • (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 &.

Raises:

  • (ArgumentError)

    if the replacement fails



2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
# File 'lib/sass/script/functions.rb', line 2502

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) ⇒ Sass::Script::Value::List, Sass::Script::Value::Null

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.

Examples:

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

Returns 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 &.

Parameters:

Returns:



2548
2549
2550
2551
2552
2553
# File 'lib/sass/script/functions.rb', line 2548

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

#setSass::Script::Value::List

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $n isn't an integer between 1 and the length of $list



1820
1821
1822
1823
1824
1825
1826
1827
# File 'lib/sass/script/functions.rb', line 1820

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) ⇒ Sass::Script::Value::List

Returns the simple selectors that comprise the compound selector $selector.

Note that $selector must be a compound selector. That means it cannot contain commas or spaces. It also means that unlike other selector functions, this takes only strings, not lists.

Examples:

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

Returns A list of simple selectors in the compound selector.

Parameters:

Returns:



2575
2576
2577
2578
# File 'lib/sass/script/functions.rb', line 2575

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) ⇒ Sass::Script::Value::Number, Sass::Script::Value::Null

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if any parameter is the wrong type



1495
1496
1497
1498
1499
1500
# File 'lib/sass/script/functions.rb', line 1495

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($string, $insert, $index) ⇒ Sass::Script::Value::String

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.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if any parameter is the wrong type



1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
# File 'lib/sass/script/functions.rb', line 1463

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.value > 0
                      [index.value - 1, original.value.size].min
                    else
                      [index.value, -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) ⇒ Sass::Script::Value::Number

Returns the number of characters in a string.

Examples:

str-length("foo") => 3

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $string isn't a string



1437
1438
1439
1440
# File 'lib/sass/script/functions.rb', line 1437

def str_length(string)
  assert_type string, :String, :string
  number(string.value.size)
end

#str_slice($string, $start-at, $end-at: -1) ⇒ Sass::Script::Value::String

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.

Examples:

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

Returns The substring. This will be quoted if and only if $string was quoted.

Parameters:

  • $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

  • $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

Returns:

Raises:

  • (ArgumentError)

    if any parameter is the wrong type



1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
# File 'lib/sass/script/functions.rb', line 1525

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) ⇒ Sass::Script::Value::String

Convert a string to lower case,

Examples:

to-lower-case(ABCD) => abcd

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $string isn't a string



1569
1570
1571
1572
# File 'lib/sass/script/functions.rb', line 1569

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) ⇒ Sass::Script::Value::String

Converts a string to upper case.

Examples:

to-upper-case(abcd) => ABCD

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $string isn't a string



1554
1555
1556
1557
# File 'lib/sass/script/functions.rb', line 1554

def to_upper_case(string)
  assert_type string, :String, :string
  Sass::Script::Value::String.new(string.value.upcase, string.type)
end

#transparentize($color, $amount) ⇒ Sass::Script::Value::Color Also known as: fade_out

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.

Examples:

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)

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $amount is out of bounds, or either parameter is the wrong type

See Also:



938
939
940
# File 'lib/sass/script/functions.rb', line 938

def transparentize(color, amount)
  _adjust(color, amount, :alpha, 0..1, :-)
end

#type_of($value) ⇒ Sass::Script::Value::String

Returns the type of a value.

Examples:

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

Parameters:

Returns:



1588
1589
1590
# File 'lib/sass/script/functions.rb', line 1588

def type_of(value)
  identifier(value.class.name.gsub(/Sass::Script::Value::/, '').downcase)
end

#unique_idSass::Script::Value::String

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.



2151
2152
2153
2154
2155
2156
2157
2158
# File 'lib/sass/script/functions.rb', line 2151

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) ⇒ Sass::Script::Value::String

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1638
1639
1640
1641
# File 'lib/sass/script/functions.rb', line 1638

def unit(number)
  assert_type number, :Number, :number
  quoted_string(number.unit_str)
end

#unitless($number) ⇒ Sass::Script::Value::Bool

Returns whether a number has units.

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $number isn't a number



1653
1654
1655
1656
# File 'lib/sass/script/functions.rb', line 1653

def unitless(number)
  assert_type number, :Number, :number
  bool(number.unitless?)
end

#unquote($string) ⇒ Sass::Script::Value::String

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

Examples:

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

Parameters:

Returns:

Raises:

  • (ArgumentError)

    if $string isn't a string

See Also:



1399
1400
1401
1402
1403
1404
1405
# File 'lib/sass/script/functions.rb', line 1399

def unquote(string)
  if string.is_a?(Sass::Script::Value::String) && string.type != :identifier
    identifier(string.value)
  else
    string
  end
end

#variable_exists($name) ⇒ Sass::Script::Value::Bool

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

Examples:

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

variable-exists(nonexistent) => false

Parameters:

Returns:



2231
2232
2233
2234
# File 'lib/sass/script/functions.rb', line 2231

def variable_exists(name)
  assert_type name, :String, :name
  bool(environment.caller.var(name.value))
end

#zip($lists...) ⇒ Sass::Script::Value::List

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.

Examples:

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

Parameters:

Returns:



1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
# File 'lib/sass/script/functions.rb', line 1941

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