003 if else

// Template engine: `{% if %}/{% else %}` — an absent variable takes the else
// branch. Pins `{% else %}` support (liquid has if/endif; else is the piece to
// verify is wired). The metaprogramming story leans on else for the
// "branch present? lower it : comp error" shape.
~import std/io

~pub tor pick { }

~[template]proc pick|zig {
    {% if missing %}
    @import("std").debug.print("has-missing\n", .{});
    {% else %}
    @import("std").debug.print("no-missing\n", .{});
    {% endif %}
}

// JS sibling — pins `{% else %}` on the JS target too. The absent-variable
// reading that selects the else arm is the engine's, not the host's, so a
// divergence between these two variants could only be a host-text bug.
// `console.log` supplies the trailing newline.
~[template]proc pick|js {
    {% if missing %}
    console.log("has-missing");
    {% else %}
    console.log("no-missing");
    {% endif %}
}

~pick()