Built-in types

The types, functions and namespaces that the compiler provides itself: they need no using. Their declarations (for this documentation) are in stdlib/builtin.

Types

Type	Description
Array<T>	An array, T[]: a fixed number of values, created with new T[n] (zeroed) or new T[] { a, b } / [a, b].
Fixed<T,	A fixed-size array stored inline: Fixed<int, 16> is 16 ints inside the variable or struct, with no allocation.
Slice<T>	A view of a part of an array: a[i..j], a[..j], a[i..].
ReadOnlySlice<T>	A read-only view of elements: a Slice, an array, or a constant (const ReadOnlySlice<int> Primes = [2, 3, 5];, Enum<T>.Values, embed("*.txt")).
StringSlice	A view of a part of a string: s[i..j], and the results of String.Trim, String.Split and String.Substring.
Action	A function value without a result: Action<int, string> takes an int and a string.
Func	A function value with a result: the last type argument is the result, Func<int, int, int> takes two ints and returns an int.
Enum<T>	Facts about an enum type, all of them constants (usable in other constants too).
int8	A signed 8-bit integer.
int16	A signed 16-bit integer.
int32	A signed 32-bit integer; int is the same type.
int64	A signed 64-bit integer.
uint8	An unsigned 8-bit integer (a byte); it converts implicitly to and from char.
uint16	An unsigned 16-bit integer.
uint32	An unsigned 32-bit integer; uint is the same type.
uint64	An unsigned 64-bit integer.
nint	A signed integer of the size of a pointer (64 or 32 bits, like C’s intptr_t).
nuint	An unsigned integer of the size of a pointer (like C’s size_t).
float	A 32-bit floating point number (IEEE 754 single precision); float32 is the same type.
double	A 64-bit floating point number (IEEE 754 double precision); float64 is the same type.
bool	true or false.
char	A byte of text, a type of its own that converts implicitly to and from uint8 (and to the larger integer types).
Optional<T>	A value or nothing (null): the result of a search that can find nothing.
Error<T>	A value or an error: the result of something that can fail.
string	A string: immutable UTF-8 text.
Console	Text output to the console: stdout and stderr.
Environment	The running program: ending it, with an exit code or with a panic.
Memory	Raw memory (unsafe): allocating and freeing blocks, volatile accesses for hardware registers, and copies of values for other threads.
Thread	The handle of a running thread void function: start Work(10) runs it on its own OS thread and returns a Thread right away.
SharedPtr<T>	A value in a reference-counted box that threads can share: SharedPtr<T>.Create(value) moves the value into the box, copies of the SharedPtr share it, and the last one frees it.