Lists and Arrays

CColon has two collection types: lists (dynamic size) and arrays (fixed size).

Lists

Lists are dynamic, ordered collections. They can grow and shrink at runtime, and they can hold values of mixed types.

Creating lists

var list numbers = [1, 2, 3, 4, 5]
var list empty = []
var list mixed = ["hello", 42, true, 3.14]

Accessing elements

Elements are accessed by index, starting at 0:

var list colors = ["red", "green", "blue"]
console.println(colors[0])    // "red"
console.println(colors[2])    // "blue"

Accessing an index out of bounds produces a runtime error.

Modifying elements

var list items = [10, 20, 30]
items[1] = 99
// items is now [10, 99, 30]

List methods

Method	Description	Returns
.length()	Number of elements	int
.append(v)	Add an element to the end	nil
.pop()	Remove and return the last element	value
.tostring()	String representation	string

var list nums = [1, 2, 3]
nums.append(4)                         // [1, 2, 3, 4]
console.println(nums.length().tostring())  // 4
var int last = nums.pop()              // last = 4, nums = [1, 2, 3]

Iterating over lists

var list fruits = ["apple", "banana", "cherry"]
for fruit in fruits {
    console.println(fruit)
}

Arrays (fixed size)

Arrays have a fixed length that is set at creation. You cannot append to or pop from an array.

Creating arrays

Use the fixed() function:

var array coords = fixed([10, 20, 30])
var array flags = fixed([true, false, true])

Accessing and modifying elements

Works the same as lists:

console.println(coords[0].tostring())    // 10
coords[1] = 99                           // [10, 99, 30]

Array methods

Method	Description	Returns
.length()	Number of elements	int
.tostring()	String representation	string

When to use arrays vs lists

Use lists when you need a collection that grows or shrinks during execution. Use arrays when the size is known and should not change. Arrays communicate intent: the reader knows the size is fixed.