Rule of Thumb / best practices for ROHD class and function

[quekyj]

In general, when should we create a class or function in dart/ROHD during the design? Any rule of thumb or best practices?

[mkorbel1]

From ROHD's perspective, one time when you do want to make a class is when you want to define a Module (e.g. class ___ extends Module). When you want something to be a Module is sometimes similar to when you want to make something a module in SystemVerilog. For example, a top-level hierarchy or backend synthesis partition should be a Module. A Module always translates into a module when converted to SystemVerilog.

SystemVerilog uses modules and functions as common ways to group functionality. In ROHD, you are not limited to only Modules to group reusable functionality, and ROHD will not generate a SystemVerilog function.

ROHD, as a generator framework, enables you to write software that generates hardware. You can use any types of software collections, architectures, design patterns, etc. including classes and functions to develop your hardware. The only time you need to explicitly define a Module as a layer of hierarchy is when you actually want there to be a formal module boundary there. Any logic generated by your software has its hierarchy and placement determined by connectivity alone, so it will end up in the "appropriate" module hierarchy as long as you follow the input/output rules of ROHD (only consume inputs of a Module within that Module, and communicate externally through outputs of that Module).

So to summarize, make a class that extends Module when you want an explicit hardware hierarchy level to be added. Otherwise, you can do whatever you like (including other classes and functions), since it's just software!

[quekyj]

So, it really depend on how the user wants to structure their code.