append($list, $val, $separator:auto) Appends a single value onto the end of a list. Unless

map_get($map, $key) Returns the value in a map associated with the given key. If the map doesn’t have such a key, returns

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

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

nth($list, $n) Gets the nth item in a list. Note that unlike some languages, the first item

selector_unify($selector1, $selector2) Unifies two selectors into a single selector that matches only elements matched by

selector_nest($selectors...) Return a new selector with all selectors in $selectors nested beneath one another

selector_replace($selector, $original, $replacement) Replaces all instances of $original with $replacement

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