8. Control flow

Linnet has runtime if and while, compile-time static for, and no recursion.

8.1 Runtime if

if is an expression over a scalar bool. Both branches must have identical result types.

8.2 static for

static for expands its body at compile time:

var x = embedding.forward(tokens)

static for layer in layers {
    x = layer.forward(x)
}

The iterable MUST be a statically known structural collection, such as a sub-block array or a compile-time integer range. The loop MUST NOT depend on runtime tensor values.

8.3 Static integer ranges

static for i in 0..Steps {
    ...
}

start..stop iterates over the integers start <= i < stop. Both bounds MUST be compile-time integers: literals, generic dimensions, or arithmetic on them. The loop variable is an i64 scalar holding the iteration's position, not a compile-time integer, so it cannot index a sub-block array or appear in a shape.

8.4 Runtime loops

var count = 0
var running = true
while running && count < MaxNew {
    ...
    count = count + 1
    running = !done
}

while repeats its body while its condition, a scalar bool checked before each iteration, holds. The var locals assigned in the body are the carried values; their types are fixed (§5.3), so shapes are invariant across iterations. The body may assign state members (§9.3), and those writes are visible after the loop. return is not allowed inside a loop. Termination is the program's responsibility. for remains reserved.

8.5 Recursion

Function, op, and block-method recursion is forbidden in the initial language version. Future recursion support MUST be explicit in this specification, not inherited from backend behavior.