// Macro Expand Runner (PyVM)
// PoC: reads AST JSON v0 from args[0] and echoes it unchanged.
// Later: call MacroBoxSpec.expand(ast_json) and print result.

function main(args) {
    if args.length() == 0 {
        print("{}")
        return 0
    }
    local j
    j = args.get(0)
    print(j)
    return 0
}