Re: [vhdl-200x] Minutes for VHDL-200X-FT meeting, San Jose Dec 4, 2003

Subject: Re: [vhdl-200x] Minutes for VHDL-200X-FT meeting, San Jose Dec 4, 2003
From: Marcus Harnisch (
Date: Tue Dec 09 2003 - 15:04:27 PST

[not a DASC member]

Hi there,

I did not participate in the meeting, so my knowledge about the items
is limited to the slides. Anyway, here are some comments:

- Arrays of Unconstrained Arrays

  I agree with Ben, that the declaration should be the same as for
  other array types.

- Context Clause Design Unit

  Inheritance, anyone? We might want to propagate project settings
  down to lower levels. Something to think about. Let the compiler
  figure how much we screwed up ;-)

- To_String

  Please. Just don't use the shorter names.

- Signal Spy

  I like the alternative using aliases. Whether ':' (colon) is the
  best option for a path separator is arguable. Are not most
  simulators using either '.' (dot) or '/' (slash)? Why another one?

- Make conditional signal assignment a ternary operator

  Why not for variables as well? Did I miss anything?

- Read Output Ports

  Can we keep that restricted to non-synthesis? If we get native
  signal spy features into VHDL, why not use that instead?

- Boolean Equivalence

  Please don't. Implicitly assuming a boolean value leads to
  confusion. We should not trade the type-safe nature of VHDL for
  (debatable) convenience. Is it really so much better to type "if
  (<signal>)", than "if (<signal> = '1')"? How about the less-obvious
  case "if (resetn)"? Should that read as "resetn = '1'" or "resetn is
  active (low)". VHDL would have to assume the former, while users
  browsing the sources would be tempted reading the latter statement
  into the code.

Short function names, reading of output ports and boolean equivalence
are not something I spend my day on wishing I had them. Code
completion (e.g. Emacs VHDL mode) helps mitigating a lot of the
"inconveniences" VHDL users have to face. I see that some proposals
would help gaining acceptance among users of The Other HDL, but that
shouldn't be driving us.

Best regards,

Marcus Harnisch               | Mint Technology, a division of LSI Logic | 200 West Street, Waltham, MA 02431
Tel: +1-781-768-0772          |

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