002 if truthy

// Template engine: `{% if %}` control block in a |template| body.
// `flag` is a provided arg; non-empty captured text -> truthy -> guarded block
// emits. Anchors the cluster.
~import std/io

~pub event maybe { flag: usize }

~proc maybe|template|zig {
    @import("std").debug.print("always\n", .{});
    {% if flag %}
    @import("std").debug.print("flag-set\n", .{});
    {% endif %}
}

~maybe(flag: 1)