simple_selectors($selector) Returns the simple

change_color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]) Changes one or more properties

str_index($string, $substring) Returns the index of the first occurrence of $substring in $string

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

str_slice($string, $start-at, $end-at:-1) Extracts a substring from $string. The substring will begin at index

length($list) Return the length of a list. This can return the number of pairs in a map as

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

to_lower_case($string) Convert a string to lower case,

function_exists($name) Check whether a function with the given name exists.

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