Loops

In Dyon there are 4 kinds of loops:

• Infinite loop
• Traditional For loop
• Mathematical loops
• Link loop

Infinite loop

#![allow(unused)]
fn main() {
loop {
    println("hi!")
    sleep(1)
}
}

An infinite loop runs runs forever, or until break is used inside it.

Tip: Use Ctrl+C to terminate an infinite loop in the Terminal window.

Traditional For loop

#![allow(unused)]
fn main() {
for i := 0; i < 10; i += 1 {
    println(i)
}
}

A traditional loop is similar to the loop in the programming language C. It takes 3 expressions:

• Initialize, called first and once, e.g. i := 0
• Condition, checked for each turn, e.g. i < 10
• Step, called after each turn, e.g. i += 1

Mathematical loops

Dyon is famous for its mathematical loops:

• for - do something for each turn
• sift - create an array out of values
• min - find the minimum value
• max - find the maximum value
• ∃/any - check whether a condition is true for any value
• ∀/all - check whether a condition is true for all values
• ∑/sum - add values to get the sum
• ∏/prod - multiply values to get the product
• ∑vec4/sum_vec4 - add 4D vectors to get the sum
• ∏vec4/prod_vec4 - multiply 4D vectors to get the product

In mathematics, it is very common to loop over an index. An index starts at 0, and increases with 1 for each turn. All mathematical loops uses the same index notation.

#![allow(unused)]
fn main() {
for i 10 {
    println(i)
}
}

This is equivalent to for i := 0; i < 10; i += 1.

You can also specify the start and end value:

#![allow(unused)]
fn main() {
for i [0, 10) {
    println(i)
}
}

Link loop

The link loop is similar to a link block, but for a repeated pattern.

#![allow(unused)]
fn main() {
list := [1, 2, 3]
println(link i {(i+1)": "list[i]})
}

All evaluated expressions are appended to the link. Expressions that do not return a value are allowed inside a link loop.

Pro-tip: A link block inside a link loop gives you an all-or-nothing behavior.

fn main() {
    people := [{name: "Homer"}, {name: "Bart"}, {name: "Marge"}]
    kids := link i {link {
        "name: "
        name := people[i].name
        if name == "Bart" {continue} else {name}
        "\n"
    }}
    print(kids)
}