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Erik Carstensen edited this page Feb 23, 2022 · 9 revisions

We want to permit group g { port p; }; here's some design sketches for how to do this.

We have some different options, which I have parameterized by how you expect the port prefix to appear in the port object name.

Some things differ between designs:

  • There is a prefix parameter, that allows you to remove or change the port. prefix in the generated name. This can have different defaults and doesn't necessary exist in group objects.

dev.port.g.p

The idea is that all ports appear under the dev.port namespace, so the g prefix appears after that.

A sibling bank b would appear as a second cousin, in dev.bank.g.b. For this reason, we need two params to define prefix, param port_portname_prefix and bank_portname_prefix, defaulting to parent.objkind == "device" #? "port." : "" (s/port/bank/ for bank_portname_prefix). Both params are available on groups, banks and ports, and the full name of a port is the sum of obj.port_portname_prefix + obj.name for all objects in the hierarchy, so in:

group g {
  port_portname_prefix = "x.";
  bank b {
    param port_portname_prefix = "y.";
    port p {
      param port_portname_prefix = "z.";
}}}

... you will get dev.x.g.y.b.z.p and dev.bank.g.b.

dev.g.p

The idea here is that the port prefix only appears directly under dev, as a common special case for top-level port objects. For others, you generally create group indirections to control the namespace.

A single param portname_prefix is available, in port, bank and group objects (not strictly necessary in groups). Its primary purpose is to suppress port. on top level, and defaults to parent.objkind == "device" #? "port." #: "" in ports, the same with s/port/bank/ in banks, and "" in groups.

group g {
  param portname_prefix = "x.";
  bank b {
    param portname_prefix = "y.";
    port p {
      param portname_prefix = "z.";
}}}

then the bank's name is dev.x.g.y.b and the port's name is dev.x.g.y.b.z.p.

dev.g.port.p

The idea here is that "all ports are prefixed with 'port.' by default". I.e., the portname_prefix param works as in the previous design, but the default value is "port." in ports, "bank." in banks, and "" in groups. This is a simple rule that arguably is a natural generalization of current behaviour, but it's probably seldom what you want so it will be common to override the param with "".

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