Global Built-in Functions

These functions are built into the compiler - you can call them anywhere without importing anything. They are distinct from methods (called on a value with a dot, like "hi".toUpper(), documented under Methods) and from packages (imported with import, documented under Packages).

Many of the maths and conversion helpers also exist as methods. Where a method form exists it is usually the idiomatic choice - for example prefer value.toNum() over number(value).

Type & reflection

typeof(value) → string

Returns the runtime type name of value: "string", "number", "boolean", "array", "object", "null", and so on.

log typeof(5)        // "number"
log typeof("hi")     // "string"
log typeof([1, 2])   // "array"

symbol() → symbol

Returns a fresh, globally-unique symbol value. Useful as an unforgeable key or sentinel.

Type conversion & construction

These cast a value to another type. The method forms (.toNum(), .toStr(), .toInt(), .toBool(), .toArray(), .toObject()) are preferred in most code - see Type methods.

Function	Result	Notes
int(value)	int	Truncates to an integer.
number(value)	number	Parses/coerces to a float.
string(value)	string	Same as value.toStr().
boolean(value)	boolean	Truthiness of value.
object(value)	object	Coerces to an object/map.
array(value)	array	Wraps or coerces to an array.

Constructors for package-backed types (these import their package automatically):

Function	Result	Purpose
map()	map	New empty Map (insertion-ordered key/value store).
set()	set	New empty Set.
canvas(w, h, color)	canvas	New drawing canvas of the given size and background colour.
xml(source)	xml	Parses source into an XML document (no argument ⇒ empty document).
make(type, n)	type	Preallocates an array or object of capacity n, e.g. make(array, 10).

Maths

Function	Result	Description
abs(n)	number	Absolute value.
round(n)	int	Round to the nearest integer.
ceil(n)	number	Round up.
floor(n)	number	Round down.
min(a, b)	number	Smaller of two values.
min(...arr)	number	Smallest of a spread array.
max(a, b)	number	Larger of two values.
max(...arr)	number	Largest of a spread array.
random(min, max)	number	Random value between min and max.
dist(x1, y1, x2, y2)	number	Euclidean distance between two points.
gcd(a, b)	int	Greatest common divisor.
lcm(a, b)	int	Lowest common multiple.
degtorad(deg)	number	Degrees → radians.
radtodeg(rad)	number	Radians → degrees.

log abs(-3)            // 3
log round(2.7)         // 3
log min(3, 7)          // 3
log max(...[4, 9, 2])  // 9
log dist(0, 0, 3, 4)   // 5

Other maths (powers, roots, trigonometry, logarithms) are available as number methods - n.sqrt(), n.sin(), n.clamp(lo, hi), … - see Number methods, or via the math package for the full set.

Encoding

Function	Result	Description
btoa(str)	string	Base64-encode a string.
atob(str)	string	Decode a Base64 string.
encodeURIComponent(str)	string	Percent-encode for use in a URL.
decodeURIComponent(str)	string	Reverse encodeURIComponent.

log btoa("hi")               // "aGk="
log atob("aGk=")             // "hi"
log encodeURIComponent("a b") // "a%20b"

Control & error handling

try(expression) → result

Runs expression, catching any error. Returns a result: ok(value) if it succeeded, or err(message) if it threw. Importing osl/result happens automatically.

auto r = try(risky())
if r.isOk() (
  log r.unwrap()
) else (
  log "failed: " ++ r.unwrapErr()
)

some(value) → option / none() → option

Construct an optional value - some(v) for a present value, none() for absence. Importing osl/option happens automatically.

ask(prompt) → result

Prints prompt and reads a line from standard input, returning a result. Also available as a string method: "Name? ".ask().

auto name = ask("What is your name? ").unwrapOr("anonymous")

Advanced

raw(goCode)

Emits goCode verbatim into the generated Go program - an escape hatch for dropping to Go. Use sparingly; it bypasses OSL's type checks.

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See also

• Statements like log / say, wait(ms), return, throw, defer are commands, not functions - see Commands.

• Methods on values: Strings, Numbers, Arrays, Objects, Types & conversion.