Generics on Protected Types

Proposal Editing Information

• Who Updates: JimLewis, <Add YourName >, ...
• Date Proposed: 2012-08-17
• Date Last Updated: 2012-08-17
• Priority:
• Complexity:
• Focus: Testbench

Requirement Summary

Add generics to protected types. Allow generics to be specified on usage of the type - in a similar way to subtype constraints.

Current Situation

When using package generics to create a data structure, the process is instantiate a package, reference the package, and then reference a type from the package. When multiple different parameterized data structures are created from the same generic package, the type names need to be instanced with fully selected path names.

Related and/or Competing Issues: Protected Type Updates

Proposed Extension, Part 1:

Add Generics to protected types to streamline parameterization of data structures.

Declaration of protected type interface

type ScoreBoardGenericPType is protected 
    generic (
        type ExpectedType ; 
        type ActualType ; 
        function check(Actual : ActualType ;  Expected : ExpectedType) return boolean 
    ) ; 
    ... 
end protected ScoreBoardGenericPType ;

Protected type instance:

type ScoreBoardPType_slv is new ScoreBoardGenericPType 
    generic map (
        ExpectedType    => std_logic_vector,  
        ActualType      => std_logic_vector,  
        check           => std_match
    ) ;  

Usage of the object

shared variable UartTxScoreboard : ScoreBoardPType_slv ; 

Proposed Extension, Part 2:

Allow generics to be specified during an object declaration in a similar manner to a subtype constraint.

Combine protected type instance and shared variable declaration

shared variable UartTxScoreboard : ScoreBoardGenericPType 
    generic map (
        ExpectedType    => std_logic_vector,  
        ActualType      => std_logic_vector,  
        check           => std_match
    ) ;  

Observation

Part 1 without part 2 gives us a solution that does not have any advantage over package generics.

Questions

Would there be restrictions on generic types that are locally instanced with respect to hierarchical references?

Can I use the generic type on an interface and have the actual specify the generics without it being on the formal?

General Comments

Important for testbench data structures

Supporters

Add your signature here to indicate your support for the proposal

-- JimLewis - 2014-12-03

-- Brent Hayhoe - 2014-12-23

-- MortenZilmer - 2015-01-21

-- PatrickLehmann - 2016-02-18

-- TorstenMeissner - 2016-05-19

-- DanielKho - 2016-10-01