Functions

Builtin functions and values, every name in scope in every file, and the methods of the language's own types. A function marked lift passes null through: given null for a parameter that takes none, it gives null. An action changes the world and is called only from a handler.

Functions

Function
`fn atan2(y: float, x: float) -> angle`	The angle from the origin to the point (`x`, `y`), from -180deg to 180deg, 0deg pointing right and clockwise positive (y grows down): the knob angle of a pointer, `atan2(p.y - cy, p.x - cx)`. An arc drawn from a fixed angle to it turns the other way once the pointer passes 180deg: add `360deg` to an angle below the arc's start.
`fn bezier(x1: float, y1: float, x2: float, y2: float) -> Easing`	A cubic bézier curve: `~ bezier(0.05, 0.9, 0.1, 1.05)`.
`fn bloom(radius: length, strength: float = 1) -> Filter`	Bloom: bright parts bleed light `radius` around them, `strength` times as bright as they are (1: as bright), `filter: bloom(12)`, `filter: bloom(12, 1.5)`. Without a GPU it draws as a glow.
`fn blur(radius: length) -> Filter`	Blurs: `backdrop: blur(16)` over your own content, `filter: blur(30)`.
`fn brightness(amount: float) -> Filter`	A colour filter: `filter: brightness(0.9)`.
`fn bytes(n: float) -> text lift`	A count of bytes as text in binary units: `bytes(1536)` is `1.5 KiB`, `bytes(disk.used)` `19.4 GiB` (one decimal below 100, none from 100; `B`, `KiB`, `MiB`, `GiB`, `TiB`, `PiB`, the unit chosen after rounding, so `bytes(1023.6)` is `1 KiB`). Null in, null out.
`fn chromatic(offset: length) -> Filter`	Chromatic aberration: red shifted `offset` right and blue `offset` left of green, `filter: chromatic(2)`. Without a GPU the node draws unfiltered.
`fn clamp(x: float, lo: float, hi: float) -> float`	`x` kept between `lo` and `hi`.
`fn conic(from: angle = 0, ...stops: color) -> paint`	A conic gradient: `conic(from: t * 60deg, $accent, $secondary, $accent)`.
`fn contrast(amount: float) -> Filter`	A colour filter changing contrast.
`fn cos(a: angle) -> float`	The cosine of an angle: `x: r * cos(a)` places a point on a circle, 0deg pointing right and angles turning clockwise, as `c.arc` reads them.
`fn crt() -> Filter`	A CRT look: a curved screen with rounded corners, scanlines, a fringe of colour and a darker rim, `filter: crt()`. No knobs. Without a GPU the node draws unfiltered.
`fn dot(size: length) -> Sprite`	A round particle sprite: `sprite: dot(3)`.
`fn dur(duration: duration, clock: bool = false) -> text lift`	A duration as text: `dur(battery.time_left)` is `45 s`, `12 min` or `2 h 5 min`; with `clock: true` it is a clock reading, `m:ss` or `h:mm:ss` (`dur(media.length, clock: true)` is `3:45`). Null in, null out.
`fn ease(curve: Curve, duration: duration) -> Easing`	A named curve over a duration: `~ ease(out_back, 300ms)`.
`fn exp(x: float) -> float`	e to the power `x`.
`fn fade(edge: Edge, size: length) -> Mask`	A mask fading toward an edge: `mask: fade(bottom, 24)`.
`fn glass(refraction: length = 12) -> Filter`	Liquid glass over what is behind it: lightly frosted, bent up to `refraction` at its rim (red and blue apart), a fresnel rim and a highlight under the pointer, `backdrop: glass()`, `backdrop: glass(20)`. Without a GPU it draws as a blur and a tint.
`fn grayscale(amount: float) -> Filter`	A colour filter: `filter: grayscale(1)`.
`fn grow(by: length) -> HitArea`	A larger hit area for a small target: `hit: grow(6)`.
`fn hue(angle: angle) -> Filter`	A colour filter turning hues: `filter: hue(30deg)`.
`fn import(source: text) -> Palette`	A palette from another scheme: `import("catppuccin:mocha")`. It must fill the whole palette schema.
`fn invert(amount: float) -> Filter`	A colour filter inverting colours.
`fn join(sep: text, ...parts: any) -> text`	Joins the parts that are not null.
`fn linear(angle: angle, ...stops: color) -> paint`	A linear gradient: `linear(45deg, $accent, $tertiary)`. Banding is removed by dithering.
`fn ln(x: float) -> float`	The natural logarithm; 0 and negative numbers have none (an error value).
`fn material(seed: color, variant: Variant = tonal_spot, dark: bool = false, contrast: float = 0) -> Palette`	A Material 3 palette from a seed colour, or from a wallpaper image (quantised off-thread and cached; the old palette holds until the new one is ready, so that form is `Async`).
`fn material(image: path, variant: Variant = tonal_spot, dark: bool = false, contrast: float = 0) -> Async<Palette>`	A Material 3 palette from a seed colour, or from a wallpaper image (quantised off-thread and cached; the old palette holds until the new one is ready, so that form is `Async`).
`fn max(a: float, b: float) -> float`	The larger of two numbers.
`fn min(a: float, b: float) -> float`	The smaller of two numbers.
`fn noise(x: float) -> float`	Smooth noise at `x`; a time signal when `x` follows `t`.
`fn num(x: float, digits: int = 0, pad: int = 0) -> text lift`	A number as text with `digits` decimals and its whole part padded with zeros to `pad` digits: `num(3.14159, digits: 2)` is `3.14`, `num(7, pad: 2)` is `07`. It rounds half away from zero on the decimals the number is written with (`num(1.005, digits: 2)` is `1.01`). Null in, null out.
`fn number(t: text) -> float? lift`	The number a text spells, or null when it spells none: `number(" 42 ")` is 42, `number("4 GB")` null. Leading and trailing white space is ignored; `1e3` and `-0.5` are numbers. Null in, null out.
`fn oklch(from: color, l: float = l, c: float = c, h: angle = h, alpha: float = alpha) -> color`	`oklch(from $surface, l: l + 0.12)`: `l`, `c`, `h` and `alpha` name the source colour's channels inside the arguments.
`fn oklch(l: float, c: float, h: angle, alpha: float = 1) -> color`	`oklch(from $surface, l: l + 0.12)`: `l`, `c`, `h` and `alpha` name the source colour's channels inside the arguments.
`fn pct(fraction: float) -> text lift`	A fraction as a percentage: `pct(battery.percent)`. Null in, null out.
`fn popin(scale: float) -> Pose`	A pose scaling in from `scale`: `enter: popin(0.8)`.
`fn pow(x: float, y: float) -> float`	`x` to the power `y`: `pow(2, 10)` is 1024.
`action propagate()`	Handlers only.
`fn radial(...stops: color) -> paint`	A radial gradient, or with `at` and `size` a radial reveal mask.
`fn radial(at: Anchor, size: length) -> Mask`	A radial gradient, or with `at` and `size` a radial reveal mask.
`fn rgb(r: float, g: float, b: float, alpha: float = 1) -> color`	A colour from red, green and blue channels.
`fn saturate(amount: float) -> Filter`	A colour filter: `filter: saturate(1.3)`.
`fn shape(shape: Shape) -> Mask`	A mask of a shape from the shape library: `mask: shape(cookie)`.
`fn sin(a: angle) -> float`	The sine of an angle (a plain number is degrees, so `pi` in it is a warning: a half turn is `180deg`): `r * sin(a)`. Of a time signal it follows time, as arithmetic does: `x: 20 * sin(t * 90deg)`.
`fn sleep(duration: duration) -> Async<()>`	Waits for `duration` inside a handler.
`fn slide(edge: Edge) -> Pose`	A pose sliding in from an edge: `enter: slide(top)`.
`fn spring(stiffness: float, damping: float) -> Spring`	A spring for `~` and the motion tokens: `spring(3000, 0.75)`.
`fn sqrt(x: float) -> float`	The square root; a negative number has none (an error value).
`fn tan(a: angle) -> float`	The tangent of an angle.
`fn tint(color: color) -> Filter`	A colour filter tinting toward a colour: `filter: tint($accent)`.
`fn wave(period: duration, phase: float = 0) -> float`	A time signal that swings once per `period`: `10 * wave(2s)`. Only the node reading it repaints, and only while visible.
`fn wipe(edge: Edge) -> SwapTransition`	A transition wiping from an edge: `transition: wipe(left)`.
`fn wobble(amplitude: length) -> Filter`	A raster wobble: rows swing up to `amplitude` sideways in a wave 40 px long that travels down every 2 s, `filter: wobble(4)`. Without a GPU the node draws unfiltered.

Values

Value	Type
`pi`	`float`	The ratio of a circle's circumference to its diameter, 3.14159…
`t`	`float`	Time signal: seconds, for `rotate: t * 20deg`.

Methods of builtin types

`color`

Method
`fn alpha(alpha: float) -> color`	The colour with opacity `alpha`: `$fg.alpha(0.65)`.
`fn mix(other: color, amount: float) -> color`	Mixes in `amount` of `other`: `$surface.mix($fg, 8%)`.
`fn lighten(amount: float) -> color`	A lighter colour.
`fn darken(amount: float) -> color`	A darker colour.

`float`

Method
`fn abs() -> float`	The absolute value.
`fn round() -> int`	The nearest whole number.
`fn floor() -> int`	The whole number at or below.
`fn ceil() -> int`	The whole number at or above.
`fn min(other: float) -> float`	The smaller of this and `other`.
`fn max(other: float) -> float`	The larger of this and `other`.
`fn clamp(lo: float, hi: float) -> float`	This kept between `lo` and `hi`.

`text`

Member
`len: int`	How many characters.
`fn upper() -> text`	The text in upper case.
`fn lower() -> text`	The text in lower case.
`fn trim() -> text`	The text without leading and trailing white space.
`fn contains(part: text) -> bool`	It holds `part`.
`fn starts_with(prefix: text) -> bool`	It starts with `prefix`.
`fn ends_with(suffix: text) -> bool`	It ends with `suffix`.
`fn split(sep: text) -> [text]`	The pieces between each `sep`.
`fn replace(from: text, to: text) -> text`	Every `from` replaced with `to`.
`fn slice(from: int, to: int? = null) -> text`	The characters from `from` up to (not including) `to`, counted from 0; without `to`, to the end. A negative index counts from the end (`name.slice(-3)` is the last three), and indices past either end stop there: `"strand".slice(1, 3)` is `tr`.
`fn index_of(part: text) -> int?`	The character index of the first `part` in it (0 for the first character, as `slice` counts), or null when it holds none.

`[T]`

A list of T items. remove_key, move and update are a keyed list's ([T] key field, or a keyed record's), K its key's type.

Member
`len: int`	How many items.
`first: T?`	The first item; null if empty.
`last: T?`	The last item; null if empty.
`fn filter(keep: fn(T) -> bool) -> [T]`	The items `keep` is true for.
`fn map(f: fn(T) -> any) -> [any]`	Each item through `f`.
`fn sort_by(by: fn(T) -> any) -> [T]`	The items ordered by `by`.
`fn take(count: int) -> [T]`	The first `count` items.
`fn skip(count: int) -> [T]`	All but the first `count` items.
`fn reverse() -> [T]`	The items in reverse order.
`fn distinct() -> [T]`	The items without repeats: the first of each equal item, in order.
`fn sum(of: fn(T) -> any) -> any`	The items added up (`xs.sum()`), or what `of` gives for each (`ws.sum(w => w.width)`); 0 for no items. Numbers of one unit.
`fn reduce(init: U, f: fn(U, T) -> U) -> U`	`init` carried through every item in order by `f`, which takes what it gave last and the item: `xs.reduce(0, (sum, x) => sum + x)`, `init` for no items. Its type is `init`'s.
`fn join(sep: text) -> text`	The text items joined with `sep`.
`fn contains(item: T) -> bool`	Whether `item` is in the list.
`fn any(test: fn(T) -> bool) -> bool`	Whether `test` is true for some item.
`fn all(test: fn(T) -> bool) -> bool`	Whether `test` is true for every item.
`fn count(test: fn(T) -> bool) -> int`	How many items `test` is true for.
`fn find(test: fn(T) -> bool) -> T?`	The first item `test` is true for, or null.
`fn index_of(test: fn(T) -> bool) -> int?`	The index of the first item `test` is true for (0 for the first item, as `xs[i]` reads it), or null.
`fn push(item: T)`	Adds `item` at the end (handlers only).
`fn insert(at: int, item: T)`	Inserts `item` at `at` (handlers only).
`fn remove(at: int)`	Removes the item at `at` (handlers only).
`fn clear()`	Removes every item (handlers only).
`fn remove_key(key: K)`	Removes the item with `key` (keyed lists, handlers only).
`fn move(key: K, to: int)`	Moves the item with `key` to `to` (keyed lists, handlers only).
`fn update(key: K, f: fn(T) -> T)`	Replaces the item with `key` by `f` of it (keyed lists, handlers only).

Functions

#Functions

#Values

#Methods of builtin types

#color

#float

#text

#[T]

Functions

Values

Methods of builtin types

`color`

`float`

`text`

`[T]`