Built-in Functions

Macros are built-in functions that perform some common tasks. Below is a list of some common macros that you can use at any stage in your CSML flows.


Return one the elements of the array passed in the first argument at random.

Useful for randomisation of dialogue parts!

say OneOf(["I like you", "You're awesome"])


Given an array, return it with its elements in a random order.

Especially useful in questions to randomize the available options!

do btn1 = Button("Blue")
do btn2 = Button("Red")
do btns = Shuffle([btn1, btn2])
say Question(
title = "Select a pill",
buttons = btns


Return whether a string is contained in another string.

say Find("needle", in="haystack") // false
say Find("yes", in="well yes, I like cheese") // true


Return the length of a given string or array

say Length("My horse is amazing") // 19
say Length([1, 2, 3]) // 3


Return a random floating point number in the range 0-1 (0 included, 1 excluded).

say Random() // 0.03196249773128712
say Random() // 0.6416423921015862


Return the largest integer less than or equal to the given number.

say Floor(1.23456) // 1

This is useful to generate a random integer in a given range:

say Floor(Random() * 5) // a random integer between 0-4 (included)
say Floor(Random() * 8) + 12 // a random integer between 12 - 19 (included)


Generate a random UUID (v1 or v4, defaults to v4)

say UUID() // "aa4b9fb4-4d37-488c-981f-8aebc4eb9eaa"
say UUID("v1") // "d0b40e8e-7ea4-11eb-9439-0242ac130002"
say UUID("v4") // "4b784011-e49b-4913-9d58-7abf4f8a56bc"


The Time() helpers lets your manipulate timestamps and dates easily.

do time = Time() // initialize a Time object at the current UTC time
do time = Time().at(2021, 03, 28, 12, 53, 20, 123) // initialize a time object at 2021-03-28T12:53:20.123Z
do time.unix() // generate the unix timestamp (in milliseconds)
do time.format() // returns an ISO8601 string
do time.format("%h%d") // returns a string with a custom format
do time = Time().parse("2021-03-28") // parse a date
do time = Time().parse("2021-03-28T12:53:20Z") // parse an ISO-formatted string
do time = Time().parse("01/01/2021", "%d/%m/%Y") // parse a custom-formatted string

CSML's Time function is based on Rust's Chrono library. All the formatting options are listed here: https://docs.rs/chrono/0.4.19/chrono/format/strftime/index.html