Loops

Loop statements execute a body repeatedly. Forge provides several loop forms for different iteration patterns.

For-In Loops

The for-in loop iterates over elements of a collection.

let names = ["Alice", "Bob", "Charlie"]
for name in names {
    say "Hello, {name}"
}

For Each Variant

The for each form is equivalent to for-in:

for each name in names {
    say "Hello, {name}"
}

Iterating Over Arrays

let nums = [10, 20, 30]
for n in nums {
    say n
}
// Output: 10, 20, 30

Iterating Over Objects

When iterating over an object, the loop variable receives each key:

let user = { name: "Alice", age: 30 }
for key in user {
    say "{key}: {user[key]}"
}

Iterating with Index

Use enumerate or a two-variable for loop to access both index and value:

let items = ["a", "b", "c"]
for i, item in items {
    say "{i}: {item}"
}
// Output: 0: a, 1: b, 2: c

Iterating Over Ranges

The range function generates a sequence of integers:

for i in range(0, 5) {
    say i
}
// Output: 0, 1, 2, 3, 4

range(start, end) produces integers from start (inclusive) to end (exclusive).

While Loops

The while loop executes as long as its condition is truthy.

let mut count = 0
while count < 5 {
    say count
    count += 1
}
// Output: 0, 1, 2, 3, 4

The condition is evaluated before each iteration. If the condition is falsy on the first check, the body never executes.

Loop (Infinite)

The loop keyword creates an infinite loop. Use break to exit.

let mut n = 0
loop {
    if n >= 3 {
        break
    }
    say n
    n += 1
}
// Output: 0, 1, 2

Repeat N Times

The repeat loop executes a body a fixed number of times.

repeat 3 times {
    say "hello"
}
// Output: hello, hello, hello

The count expression is evaluated once before the loop begins. The body executes exactly that many times.

Break

The break statement exits the innermost enclosing loop immediately.

for i in range(0, 100) {
    if i == 5 {
        break
    }
    say i
}
// Output: 0, 1, 2, 3, 4

break can be used with for, while, loop, and repeat.

Continue

The continue statement skips the rest of the current iteration and proceeds to the next one.

for i in range(0, 5) {
    if i == 2 {
        continue
    }
    say i
}
// Output: 0, 1, 3, 4

Nested Loops

Loops can be nested. break and continue apply to the innermost loop only.

for i in range(0, 3) {
    for j in range(0, 3) {
        if j == 1 {
            break       // exits inner loop only
        }
        say "{i},{j}"
    }
}
// Output: 0,0  1,0  2,0

Loop Scope

Variables declared inside a loop body are scoped to each iteration:

for i in range(0, 3) {
    let msg = "iteration {i}"
    say msg
}
// msg is not accessible here

The loop variable itself (i in for i in ...) is scoped to the loop body.

Wait in Loops

The wait statement can be used inside loops to introduce delays:

repeat 3 times {
    say "tick"
    wait 1 second
}