P1076 February 18, 2016 Meeting Minutes

Attendees:

• Brent Hayhoe, Rob Gaddi, Patrick Lehmann, Jim Lewis, Peter Flake, Ernst Christen, Jing Pang

Agenda:

Meeting Discussion

• What's Next - see PrivateDocuments file: _summary_vhdl_requirements_priority.xlsx
• Garbage Collection (item 31)
  • What stops a simulator from doing this now? Nothing
    • The language allows this (9.3.7 note 2), however, we cannot count on it happening
  • Cannot be handled at the user level
  • implied deallocate
  • Use model: to_string using write(buf, ...)
  • Allow user to suggest deallocation with deallocate
  • Good upside and little downside (simulator speed issue?)
  • Reference count (issues with a ring), Mark & sweep
• Path_name, Shared Variables, and Subprograms
  • path_name and instance_name follow where the protected type is declared
  • We need an attribute that follows where the shared variable is declared
    • Exposes instance to implementation
  • within a protected type, use of this'instance_name makes sense (see Rob's notes)
  • within a regular subprogram, intent is to go back to the line that called the subprogram.
    • Intelligent call stack
    • Information model is already in VHPI
    • Maybe this type of information should be gathered via std.env
  • May require 2 separate solutions one for PT and one for regular subprograms
• Composition of protected types
  • Deriving capability from existing objects and layering rather than recreating
  • Look at Suave tagged types for additional ideas (ADA has tagged types)
• Generics for Protected Types
  • Look also at ADA discriminants as an alternative - discriminant is more like a subtype constraint
  • Coordinate with interfaces and bundles
  • Each generic instance of a type is a unique type (and likely needs to be for PT type applications)
• Vector Literal Introspection
  • For single dimensional array objects, look at the object itself to help disambiguate subprogram calls
  • Compile time issue.
  • Is it a valuable enough change to justify the effort in implementing it?
  • Need someone who is really interested in this to take it further
• Conditional Expression or Operator
  • Addresses issues with initializing constants, signals, and variables
  • Straight forward add implementation 2 and justify that it makes the language symmetric with assignment capability
  • Implementation 1 would require some analysis when it is mixed with a conditional assignment.
  • It seems to be a no-brainer to do it for initializers - leverage variable assignment capability
  • For a general expression it only makes sense if it generalizes many different things.
    • Complication is in signal assignments, as when allows waveform elements
• Stopped at line 37

Review and Approve Meeting Minutes:

Rob, Ernst

Next Meeting: Thursday February 25, 2016 11 am Pacific

Previous Meeting: Thursday February 11, 2016