Builtins reference

Tantu's builtins are callable names available in every program, with no import needed. A few (chan, send, recv, close, sleep, print) are compiler intrinsics backed by dedicated bytecode; the rest are ordinary library functions. Referencing a builtin outside call position is a compile error; they aren't first-class values.

In the signatures below, T and U stand for any type.

Name	Signature	Notes
print	(T) -> Unit	any value; prints via the PRINT op
str	(T) -> Str	render to a string (a Str is returned unquoted)
len	(List[T]) -> Int, (Str) -> Int	length; two overloads
push	(List[T], T) -> List[T]	returns a NEW list (lists are immutable by convention)
get	(List[T], Int) -> Option[T]	safe index; None when out of range
concat	(List[T], List[T]) -> List[T]	join two lists
range	(Int, Int) -> List[Int]	half-open [a, b)
float	(Int) -> Float	widen an Int
trunc	(Float) -> Int	truncate toward zero
parse_int	(Str) -> Option[Int]	None if not an integer
split	(Str, Str) -> List[Str]	split on a separator
substring	(Str, Int, Int) -> Str	half-open, clamps to bounds
chars	(Str) -> List[Str]	explode into single-character strings
chan[T](n?)	() -> Chan[T] / (Int) -> Chan[T]	make a channel (optional buffer size)
send	(Chan[T], T) -> Unit	send a value (blocks when full)
recv	(Chan[T]) -> Option[T]	receive; None when the channel is closed + drained
close	(Chan[T]) -> Unit	close a channel
sleep	(Int) -> Unit	yield for N milliseconds

Generated

This table is generated from the language's builtin registry (tantu/prelude.py) and Appendix A of the design spec, so it stays in sync with the interpreter.

See Types & no-null for how Option and Result (returned by get, parse_int, and recv) are consumed, and Collections for lists, tuples, and strings.