Function c_call_lambda_impl

tutorials/integration/c/04_callbacks.c:82–106

----------------------------------------------------------------------- Interop: c_call_lambda — receives a lambda and calls it daslang signature: def c_call_lambda(callback : lambda<(a:int; b:float) : string>; a : int; b : float) : string Mangled: "s 0 @ i f" "0 @" — lambda (single @, captures variables) Important: when calling a lambda, the FIRST argument must be the lambda itself (it

//   [0] = lambda, [1] = int a, [2] = float b
// -----------------------------------------------------------------------
vec4f c_call_lambda_impl(das_context * ctx, das_node * node, vec4f * args) {
    (void)node;
    das_lambda * lambda = das_argument_lambda(args[0]);
    int    a = das_argument_int(args[1]);
    float  b = das_argument_float(args[2]);

    printf("[C] calling lambda with (%d, %.2f)\n", a, b);

    // Lambda arguments: first is the lambda itself, then the actual args.
    vec4f lmb_args[3];
    lmb_args[0] = das_result_lambda(lambda);    // capture context
    lmb_args[1] = das_result_int(a);
    lmb_args[2] = das_result_float(b);

    vec4f ret = das_context_eval_lambda(ctx, lambda, lmb_args);
    char * ex = das_context_get_exception(ctx);
    if (ex) {
        printf("[C] exception in lambda: %s\n", ex);
        return das_result_string(NULL);
    }

    char * str = das_argument_string(ret);
    printf("[C] lambda returned: \"%s\"\n", str);
    return ret;
}

// -----------------------------------------------------------------------
// -----------------------------------------------------------------------