Control Flow

Overview

Echo supports the usual control flow for scripting: branching, loops, and loop control statements.

Syntax

if condition {
    say("yes");
} else {
    say("no");
}

while condition {
    say("loop");
}

for i: int in 0..10 by 1 {
    say(i);
}

foreach item: str in items {
    say(item);
}

Example

for i: int in 0..5 {
    if i == 2 {
        continue;
    }

    if i == 4 {
        break;
    }

    say(i);
}

Output

0
1
3

Notes

if, else, and else if

Echo supports the familiar else if source form.

while

Runs while the condition stays truthy.

for

• .. means inclusive end
• ... means exclusive end
• by sets the step
• loop variable type must be int

foreach

Each item is checked against the declared loop variable type at runtime.

Common Mistakes

Using the wrong loop variable type in for

for i: str in 0..10 {
    say(i);
}

Using break outside a loop

That raises a syntax error.

Forgetting braces

Echo does not support implicit blocks.

Current Limitation

• for ... by 0 is not guarded and can loop forever.

See Also

• Loops Reference
• Operators
• Errors and Troubleshooting