Arrays & Slices

Array length is part of the type and must be known at compile time.

Arrays

Int[3] values = [1, 2, 3];

// Length mismatch is an error.
// Int[5] bad = [1, 2, 3];

Heap arrays use an owning pointer:

Int[3]^ owner = new [1, 2, 3];
print(owner.length);

Length Inference

Use _ in the array length or infer the whole type:

_ a = [1, 2, 3];
Int[_] b = [1, 2, 3];
Int[3] c = [1, 2, 3];

Mutability

Element mutability and outer binding mutability are separate layers:

Int![_] items = [1, 2, 3];
items[1] = 4;

Int[_]! slot = [1, 2, 3];
slot = [4, 5, 6];

Int![_]! both = [1, 2, 3];
both[1] = 4;
both = [4, 5, 6];

Nested Arrays

Jiang does not need a separate multidimensional array form. Repeated array suffixes build nested arrays:

Int[2][3] matrix = [[1, 2], [3, 4], [5, 6]];

matrix[0];    // [1, 2]
matrix[0][1]; // 2

Read Int[2][3] as Int -> Int[2] -> Int[2][3].

Int?[2][3] nullable_items = [[1, null], [3, 4], [5, 6]];
Int?[2]?[3] nullable_rows = [[1, null], null, [5, 6]];

Slices

T[] is a runtime-length view over contiguous storage. It does not own the storage.

Int[_] values = [1, 2, 3];
Int[] view = values[..];

print(view.length);

Indexing a slice can produce an element reference:

_ item_ref = view[1]$.ref();

Many Raw Pointers

T[*] is a raw pointer form for contiguous elements without a length:

UInt8[*] data;
Int length;

UInt8 first = data[0];

T* is a single-object raw pointer and is not used for free position movement. Use T[*] for position-based contiguous-memory access, and use T[] when Jiang code needs a length-bearing view.