RE: [vhdl-200x-ft] Suggested changes to FT09

Steve,

The idea of a literal is that it represents a value directly without having
to evaluate any operations.  Moreover, a bit string literal is currently a
lexical element, so no separator characters are allowed within it.
Specifying a primary as the length of a bit string literal would mean that
the bit string literal could no longer be a lexical element; it would have
to be a form of expression.

Based on John's original proposal that the size be a primary that is not
necessarily static, the following would be legal:

    (to_integer(my_signal'last_value) + 1) SX"F"

I would hardly call that a literal.  It's size and value is going to depend
dynamically on the history of the signal.  It looks more like a typo where
an operator got omitted.

For the occasional case where the size needs to be determined other than by
a literal integer, we can make use of the resize function.  For the 99%
case, having the size specified as a literal integer keeps things simpler,
both conceptually and in implementation terms.

Cheers,

PA

--
Dr. Peter J. Ashenden                        peter@ashenden.com.au
Ashenden Designs Pty. Ltd.                   www.ashenden.com.au
PO Box 640                                   Ph:  +61 8 8339 7532
Stirling, SA 5152                            Fax: +61 8 8339 2616
Australia                                    Mobile: +61 414 70 9106


> -----Original Message-----
> From: owner-vhdl-200x-ft@eda.org 
> [mailto:owner-vhdl-200x-ft@eda.org] On Behalf Of Stephen A. Bailey
> Sent: Thursday, 17 March 2005 08:30
> To: vhdl-200x-ft@eda.org
> Subject: RE: [vhdl-200x-ft] Suggested changes to FT09
> 
> 
> If there's no reason to make it restrictive to a literal, 
> then primary is more general and powerful.
> 
> -Steve Bailey
> 
> > The size of decimal literals has been updated in the proposal
> > to reflect Peter's mail.
> > 
> > As for making the size a literal instead of a primary, I
> > don't have any problems with that.  I just thought it would 
> > be neat to be able to dynamically size literals but I didn't 
> > have any real problem in mind when I made the size a primary.
> > 
> > Regards,
> >    John
> > 
> > Peter Ashenden wrote:
> > > Folks,
> > > 
> > > I'm just going through FT09, bit-string literals.  I 
> discussed this
> > > with John R last November and summarized our conclusions in 
> > an email
> > > on the
> > > reflector:
> > > 
> > > http://www.eda-twiki.org/vhdl-200x/vhdl-200x-ft/hm/0311.html
> > > 
> > > I didn't get any responses.  Do I take that as tacit
> > approval?  If so,
> > > we need to update the proposal doc before it goes to WG vote.
> > > 
> > > Cheers,
> > > 
> > > PA
> > > --
> > > Dr. Peter J. Ashenden                        peter@ashenden.com.au
> > > Ashenden Designs Pty. Ltd.                   www.ashenden.com.au
> > > PO Box 640                                   Ph:  +61 8 8339 7532
> > > Stirling, SA 5152                            Fax: +61 8 8339 2616
> > > Australia                                    Mobile: +61 
> 414 70 9106
> > > 
> > 
> > 
> > -- 
> > -- mailto: johnr@model.com     phone: (503)685-0864
> > --   http://www.model.com        fax: (503)685-0921
> > --
> > 
> > 
>