control-flow.md

Control Flow

Lang control flow is expression-oriented in a few places, but it still maps closely to Python statement execution.

Syntax

• Functions use fn name(args) { ... }.
• A function body implicitly returns its final expression.
• Conditionals use if ... { ... } else { ... }.
• Infinite loops use loop { ... }.
• Conditional loops use while ... { ... }.
• Iteration uses for item in iterable { ... }.
• Signals use $name = expr.
• Reactive statements use $ { ... }.

Examples

Functions and implicit return

fn add(a, b) { a + b }
print(add(2, 4))

Conditionals

if true { loop {} } else {}

for over a range

for x in 1..3 {
    print(x)
}

Signals

$a = 1
$b = $a + 1
print($b)
$a = 2
print($b)

Reactive statements

$ {
    print("changed")
}

Notes

• The last expression in a function body becomes return ... in generated Python.
• Empty blocks transpile to pass.
• Signals are runtime-backed values. Updating one signal re-evaluates dependent signals.
• Reactive statements are public syntax, but the current tests only validate signal update behavior directly; keep examples minimal and semantic claims conservative.