Sass Other functions

variable-exists(red)    // checks for $red
mixin-exists(red-text)  // checks for @mixin red-text
function-exists(redify)

global-variable-exists(red)

selector-append('.menu', 'li', 'a')   // .menu li a
selector-nest('.menu', '&:hover li')  // .menu:hover li
selector-extend(...)
selector-parse(...)
selector-replace(...)
selector-unify(...)

floor(3.5)
ceil(3.5)
round(3.5)
abs(3.5)

min(1, 2, 3)
max(1, 2, 3)

percentage(.5)   // 50%
random(3)        // 0..3

unit(3em)        // 'em'
unitless(100px)  // false

unquote('hello')
quote(hello)

to-upper-case(hello)
to-lower-case(hello)

str-length(hello world)
str-slice(hello, 2, 5)     // "ello" - it's 1-based, not 0-based
str-insert("abcd", "X", 1) // "Xabcd"