How to generate a parameter array

Question

I am now developing a management unit that controls several IPs through corresponding control-fsm. These IPs are grouped in several group, and each group are controlled by one control-fsm. Thus I have a control_fsm_template and a ip_template, and in each control_fsm there is a parameter ip_list to record all IPs controlled by this FSM:

template control_fsm_template {
    param ip_list : sequence (ip_template);
    param ip_list default undefined;
    method gm1() {
        foreach ip in ip_list {
            if (ip.p1) ip.m1();
        }
    }
}
template ip_template {
    param p1;
    param p2;
    connect c1;
    port c2;
    method m1() {}

    method m2() {}
} 


group ip_1 is (ip_template);
group ip_2 is (ip_template);
group control_fsm1 is (control_fsm_template) {
    param ip_list = [ip_1, ip_2];
}

group ip_3 is (ip_template);
group ip_4 is (ip_template);
group control_fsm2 is (control_fsm_template) {
    param ip_list = [ip_3, ip_4];
}

DMLC reports error: error: not a value: [ip_1, ip_2]

And then I changed the code to:

template ip_group1_template is (ip_template);
template ip_group2_template is (ip_template);
group ip_1 is (ip_group1_tempalte);
group ip_2 is (ip_group1_template);
group control_fsm1 is (control_fsm_template) {
    param ip_list = each ip_group1_template in (dev);
}
group ip_3 is (ip_group2_tempalte);
group ip_4 is (ip_group2_template);
group control_fsm2 is (control_fsm_template) {
    param ip_list = each ip_group2_template in (dev);
}

Then DMLC reports error: error: wrong type in assignment got: list of trait ip_group1_template expect: list of trait ip_template

Can you please expand a bit on how you intend to use the inner_group parameter, perhaps with a concrete code snippet that dmlc reports errors on? — Erik Carstensen, Jan 10 '23 at 14:27
Depending on how the param is used, this may or may not be a duplicate of https://stackoverflow.com/questions/75073681/cannot-use-variable-index-in-a-constant-list — Erik Carstensen, Jan 11 '23 at 10:52
Can you please edit the question and fold that clarification into it? Normally I would suggest an edit but can't do this now because stackoverflow is overwhelmed. — Erik Carstensen, Jan 12 '23 at 16:39
Hi Erik, I updated the post, could you please help to have a look again? Many thanks! — user20973675, Jan 16 '23 at 03:22
Good question! In particular, the second part of the question is interesting, and the question reduces to "why you cannot cast a `sequence(X)` to `sequence(Y)`, given that `template X is Y`". — Erik Carstensen, Jan 16 '23 at 08:11

score 0 · Accepted Answer · answered Jan 16 '23 at 08:27

The problem in your first attempt is that [] lists are not true values; they are purely compile-time entities that only support three operations: #foreach, #select, and direct indexing with a constant; therefore you cannot assign them to a typed parameter. The only way to construct values of type sequence(X) is currently each .. in .. expressions, as you correctly realized in your second attempt. The problem there is instead that DML doesn't offer a way to convert a sequence(X) into a sequence(Y), even if template Y is X. This would be a valid feature request.

The simplest solution is to use nested groups, so you can say collect all instances within a subhierarchy instead of dev:

template ip_group1_template is (ip_template);
template ip_group2_template is (ip_template);
group fsm1 {
    group ip_1 is (ip_group1_tempalte);
    group ip_2 is (ip_group1_template);
}
group control_fsm1 is (control_fsm_template) {
    param ip_list = each ip_template in (fsm1);
}
group fsm2 {
    group ip_3 is (ip_group2_tempalte);
    group ip_4 is (ip_group2_template);
}
group control_fsm2 is (control_fsm_template) {
    param ip_list = each ip_template in (fsm2);
}

How to generate a parameter array

1 Answers1