## Built-in Functions
### red(color)
Return the red component of the given `color`.
red(#c00)
// => 204
### green(color)
Return the green component of the given `color`.
green(#0c0)
// => 204
### blue(color)
Return the blue component of the given `color`.
blue(#00c)
// => 204
### alpha(color)
Return the alpha component of the given `color`.
alpha(#fff)
// => 1
alpha(rgba(0,0,0,0.3))
// => 0.3
### dark(color)
Check if `color` is dark:
dark(black)
// => true
dark(#005716)
// => true
dark(white)
// => false
### light(color)
Check if `color` is light:
light(black)
// => false
light(white)
// => true
light(#00FF40)
// => true
### hue(color)
Return the hue of the given `color`.
hue(hsla(50deg, 100%, 80%))
// => 50deg
### saturation(color)
Return the saturation of the given `color`.
saturation(hsla(50deg, 100%, 80%))
// => 100%
### lightness(color)
Return the lightness of the given `color`.
lightness(hsla(50deg, 100%, 80%))
// => 80%
### push(expr, args...)
Push the given `args` to `expr`.
nums = 1 2
push(nums, 3, 4, 5)
nums
// => 1 2 3 4 5
Aliased as `append()`
### unshift(expr, args...)
Unshift the given `args` to `expr`.
nums = 4 5
unshift(nums, 3, 2, 1)
nums
// => 1 2 3 4 5
Aliased as `prepend()`
### keys(pairs)
Return keys in the given `pairs`:
pairs = (one 1) (two 2) (three 3)
keys(pairs)
// => one two three
### values(pairs)
Return values in the given `pairs`:
pairs = (one 1) (two 2) (three 3)
values(pairs)
// => 1 2 3
### typeof(node)
Return type of `node` as a string.
type(12)
// => 'unit'
typeof(12)
// => 'unit'
typeof(#fff)
// => 'rgba'
type-of(#fff)
// => 'rgba'
Aliased as `type-of` and `type`.
### unit(unit[, type])
Return a string for the type of `unit` or an empty string,
or assign the given `type` without unit conversion.
unit(10)
// => ''
unit(15in)
// => 'in'
unit(15%, 'px')
// => 15px
unit(15%, px)
// => 15px
### match(pattern, string)
Test if `string` matches the given `pattern`.
match('^foo(bar)?', foo)
match('^foo(bar)?', foobar)
// => true
match('^foo(bar)?', 'foo')
match('^foo(bar)?', 'foobar')
// => true
match('^foo(bar)?', 'bar')
// => false
### abs(unit)
abs(-5px)
// => 5px
abs(5px)
// => 5px
### ceil(unit)
ceil(5.5in)
// => 6in
### floor(unit)
floor(5.6px)
// => 5px
### round(unit)
round(5.5px)
// => 6px
round(5.4px)
// => 5px
**Note:** All rounding functions can accept optional `precision` argument â you can pass the number of digits you want to save after the period:
ceil(5.52px,1)
// => 5.6px
floor(5.57px,1)
// => 5.5px
round(5.52px,1)
// => 5.5px
### min(a, b)
min(1, 5)
// => 1
### max(a, b)
max(1, 5)
// => 5
### even(unit)
even(6px)
// => true
### odd(unit)
odd(5mm)
// => true
### sum(nums)
sum(1 2 3)
// => 6
### avg(nums)
avg(1 2 3)
// => 2
### join(delim, vals...)
Join the given `vals` with `delim`.
join(' ', 1 2 3)
// => "1 2 3"
join(',', 1 2 3)
// => "1,2,3"
join(', ', foo bar baz)
// => "foo, bar, baz"
join(', ', foo, bar, baz)
// => "foo, bar, baz"
join(', ', 1 2, 3 4, 5 6)
// => "1 2, 3 4, 5 6"
### hsla(color | h,s,l,a)
Convert the given `color` to an `HSLA` node,
or h,s,l,a component values.
hslaa(10deg, 50%, 30%, 0.5)
// => HSLA
hslaa(#ffcc00)
// => HSLA
### hsla(color | h,s,l)
Convert the given `color` to an `HSLA` node,
or h,s,l component values.
hsla(10, 50, 30)
// => HSLA
hsla(#ffcc00)
// => HSLA
### rgba(color | r,g,b,a)
Return `RGBA` from the r,g,b,a channels or provide a `color` to tweak the alpha.
rgba(255,0,0,0.5)
// => rgba(255,0,0,0.5)
rgba(255,0,0,1)
// => #ff0000
rgba(#ffcc00, 0.5)
// rgba(255,204,0,0.5)
Alternatively, Stylus supports the `#rgba` and `#rrggbbaa` notations as well:
#fc08
// => rgba(255,204,0,0.5)
#ffcc00ee
// => rgba(255,204,0,0.9)
### rgb(color | r,g,b)
Return a `RGBA` from the r,g,b channels or cast to an `RGBA` node.
rgb(255,204,0)
// => #ffcc00
rgb(#fff)
// => #fff
### lighten(color, amount)
Lighten the given `color` by `amount`. This function is
unit-sensitive, for example supporting percentages as shown
below.
lighten(#2c2c2c, 30)
// => #787878
lighten(#2c2c2c, 30%)
// => #393939
### darken(color, amount)
Darken the given `color` by `amount`. This function is
unit-sensitive. For example, note the percentages below.
darken(#D62828, 30)
// => #551010
darken(#D62828, 30%)
// => #961c1c
### desaturate(color, amount)
Desaturate the given `color` by `amount`.
desaturate(#f00, 40%)
// => #c33
### saturate(color, amount)
Saturate the given `color` by `amount`.
saturate(#c33, 40%)
// => #f00
### invert(color)
Inverts the color. The red, green, and blue values are inverted, while opacity is left alone.
invert(#d62828)
// => #29d7d7
### unquote(str | ident)
Unquote the given `str` and returned as a `Literal` node.
unquote("sans-serif")
// => sans-serif
unquote(sans-serif)
// => sans-serif
unquote('1px / 2px')
// => 1px / 2px
### s(fmt, ...)
The `s()` function is similar to `unquote()`, in that it returns
a `Literal` node, however it accepts a format string much like C's `sprintf()`. Currently the only specifier is `%s`.
s('bar()');
// => bar()
s('bar(%s)', 'baz');
// => bar("baz")
s('bar(%s)', baz);
// => bar(baz)
s('bar(%s)', 15px);
// => bar(15px)
s('rgba(%s, %s, %s, 0.5)', 255, 100, 50);
// => rgba(255, 100, 50, 0.5)
s('bar(%Z)', 15px);
// => bar(%Z)
s('bar(%s, %s)', 15px);
// => bar(15px, null)
Check out the `%` string operator for equivalent behaviour.
### operate(op, left, right)
Perform the given `op` on the `left` and `right` operands:
op = '+'
operate(op, 15, 5)
// => 20
### length([expr])
Parenthesized expressions may act as tuples, the `length()` function returns the length of such expressions.
length((1 2 3 4))
// => 4
length((1 2))
// => 2
length((1))
// => 1
length(())
// => 0
length(1 2 3)
// => 3
length(1)
// => 1
length()
// => 0
### warn(msg)
Warn with the given error `msg`, does not exit.
warn("oh noes!")
### error(msg)
Exits with the given error `msg`.
add(a, b)
unless a is a 'unit' and b is a 'unit'
error('add() expects units')
a + b
### last(expr)
Return the _last_ value in the given `expr`:
nums = 1 2 3
last(nums)
last(1 2 3)
// => 3
list = (one 1) (two 2) (three 3)
last(list)
// => (three 3)
### p(expr)
Inspect the given `expr`:
fonts = Arial, sans-serif
p('test')
p(123)
p((1 2 3))
p(fonts)
p(#fff)
p(rgba(0,0,0,0.2))
add(a, b)
a + b
p(add)
stdout:
inspect: "test"
inspect: 123
inspect: 1 2 3
inspect: Arial, sans-serif
inspect: #fff
inspect: rgba(0,0,0,0.2)
inspect: add(a, b)
### opposite-position(positions)
Return the opposites of the given `positions`.
opposite-position(right)
// => left
opposite-position(top left)
// => bottom right
opposite-position('top' 'left')
// => bottom right
### image-size(path)
Returns the `width` and `height` of the image found at `path`. Lookups are performed in the same manner as `@import`, altered by the `paths` setting.
width(img)
return image-size(img)[0]
height(img)
return image-size(img)[1]
image-size('tux.png')
// => 405px 250px
image-size('tux.png')[0] == width('tux.png')
// => true
### add-property(name, expr)
Adds property `name`, with the given `expr` to the closest block.
For example:
something()
add-property('bar', 1 2 3)
s('bar')
body
foo: something()
yields:
body {
bar: 1 2 3;
foo: bar;
}
Next the "magic" `current-property` local variable comes into play. This variable is automatically available to function bodies, and contains an expression with the current property's name, and value.
For example if we were to inspect this local variable using `p()`, we
get the following:
p(current-property)
// => "foo" (foo __CALL__ bar baz)
p(current-property[0])
// => "foo"
p(current-property[1])
// => foo __CALL__ bar baz
Using `current-property` we can take our example a bit further, and duplicate the property with new values, and a conditional to ensure the function is only used within a property value.
something(n)
if current-property
add-property(current-property[0], s('-webkit-something(%s)', n))
add-property(current-property[0], s('-moz-something(%s)', n))
s('something(%s)', n)
else
error('something() must be used within a property')
body {
foo: something(15px) bar;
}
yields:
body {
foo: -webkit-something(15px);
foo: -moz-something(15px);
foo: something(15px) bar;
}
If you noticed in the example above, `bar` is only present for the initial call, since we returned `something(15px)`, it remained in-place within the expression, however the others do not take the rest of the expression into account.
Our more robust solution below, defines a function named `replace()` which clones the expression to prevent mutation, replaces the string value of an expression with another, and returns the cloned expression. We then move on to replace `__CALL__` within the expressions, which represents the cyclic call to `something()`.
replace(expr, str, val)
expr = clone(expr)
for e, i in expr
if str == e
expr[i] = val
expr
something(n)
if current-property
val = current-property[1]
webkit = replace(val, '__CALL__', s('-webkit-something(%s)', n))
moz = replace(val, '__CALL__', s('-moz-something(%s)', n))
add-property(current-property[0], webkit)
add-property(current-property[0], moz)
s('something(%s)', n)
else
error('something() must be used within a property')
yields:
body {
foo: foo -webkit-something(5px) bar baz;
foo: foo -moz-something(5px) bar baz;
foo: foo something(5px) bar baz;
}
Our implementation is now fully transparent both in regards to the property it is called within, and the position of the call. This powerful concept aids in transparent vendor support for function calls, such as gradients.
### Undefined Functions
Undefined functions will output as literals, so for example
we may call `rgba-stop(50%, #fff)` within our css, and it will
output as you would expect. We can use this within helpers as well.
In the example below we simply define the function `stop()` which
returns the literal `rgba-stop()` call.
stop(pos, rgba)
rgba-stop(pos, rgba)
stop(50%, orange)
// => rgba-stop(50%, #ffa500)
