modeling-app/docs/kcl-lang/arrays.md

title, excerpt, layout

title	excerpt	layout
Arrays and ranges	Documentation of the KCL language for the Zoo Design Studio.	manual

Arrays are sequences of values.

Arrays can be written out as array literals using a sequence of expressions surrounded by square brackets, e.g., ['hello', 'world'] is an array of strings, [x, x + 1, x + 2] is an array of numbers (assuming x is a number), [] is an empty array, and ['hello', 42, true] is a mixed array.

A value in an array can be accessed by indexing using square brackets where the index is a number, for example, arr[0], arr[42], arr[i] (where arr is an array and i is a (whole) number).

There are some useful functions for working with arrays in the standard library, see std::array for details.

Array types

Arrays have their own types: [T] where T is the type of the elements of the array, for example, [string] means an array of strings and [any] means an array of any values.

Array types can also include length information: [T; n] denotes an array of length n (where n is a number literal) and [T; 1+] denotes an array whose length is at least one (i.e., a non-empty array). E.g., [string; 1+] and [number(mm); 3] are valid array types.

Ranges

Ranges are a succinct way to create an array of sequential numbers. The syntax is [start .. end] where start and end evaluate to whole numbers (integers). Ranges are inclusive of the start and end. The end must be greater than the start. Examples:

[0..3]      // [0, 1, 2, 3]
[3..10]     // [3, 4, 5, 6, 7, 8, 9, 10]
x = 2
[x..x+1]    // [2, 3]

The units of the start and end numbers must be the same and the result inherits those units.