Arrays

Arrays in osl are dynamic, Python-like data structures that can store heterogeneous elements (integers, floats, characters, or other arrays).

Declaration and Initialization

Arrays can be created in two ways:

// Dynamic initialization with values
var arr := [1, 2+5, 3, 4, 5];  // arr = [1, 7, 3, 4, 5]

// Nested arrays
var nested := [1, [2, 3, [4, 5]], 6, 7];

// Fixed-size declaration (initialized to 0)
var matrix[2][3][4];  // 3D array
var lst[13];          // 1D array

Accessing and Modifying

Arrays use zero-based indexing:

var arr := [1, [2, 3, [4, 5]], 6, 7];
log arr[0];     // Prints 1 (first element)
log arr[3];     // Prints 7 (last element)

// Nested access
var x := arr[1][0] + arr[1][2][1];      // Computes x using multi-dimensional indexing

// Modification
arr[1][2][x - 7] := 10;     // Modifies nested element
log arr[1][2][0];       // Prints 10

Multi-dimensional Arrays

osl supports multi-dimensional arrays through nesting:

// Creating and initializing a 2D array
var arr[11][10];
var i := 0;
while (i < 11) {
    var j := 0;
    while (j < 10) {
        arr[i][j] := 10*i + j;
        j := j + 1;
    }
    i := i + 1;
}
log arr[5][5];  // Prints 55

Dynamic Sizing

Arrays created with [] can hold any number of elements, while declared arrays with [n] have fixed dimensions.

Type System

In the typed version of osl, array types are explicitly declared:

var i32[2][3] matrix;  // 2x3 matrix of 32-bit integers
var i32 arr := {1, 2, 3};  // Array of integers using curly braces

Implementation Details

Arrays are implemented as heap-allocated Value arrays, supporting dynamic sizing and heterogeneous elements. The VM handles array operations with opcodes like MAKE_ARRAY, MAKE_ARRAY_DECL, ARR_ACC, and STORE.