IEEE P1164 Working Group - Change Proposal

ID:	  CP-009

Proposer: Peter Ashenden <peter@ashenden.com.au>
	  (Based on requirements gathering)

Status:	  Proposed (1-Jun-2001)
	  Analyzed (07-Dec-2002)
	  Resolved (17-Feb-2003)

Summary:  Provide 'image attribute

Detail:

(From slides presented at VIUF-1999)

[Provide] image attribute for one dimensional arrays of type bit and
std_logic

Workshop summary

  - pass to VHDL 200x for all enumerated types


Analysis:

	By Peter Ashenden <peter@ashenden.com.au>, 07-Dec-2002

	The 'image attribute is defined in the base VHDL standard.
	There is no mechanism to extend the attribute to accept
	further prefix types.  Hence any proposal for extending the
	attribute must be considered by the VASG rather than the P1164
	Working Group.

	Note that the requirement to be able to produce a string
	representation of a std_logic_vector or std_ulogic_vector
	value can be met by text I/O procedures that work in the same
	way as the std.textio.write procedures.  Such procedures
	could be used to write into a string variable designated by a
	LINE access variable.  CP-007 addresses text I/O procedures
	for 1164.


Resolution:

  Analysis accepted

  Member votes: Accept 13 (100%)   Reject 0 (0%)   Abstain 0 (0%)
  All votes:    Accept 15 (100%)   Reject 0 (0%)   Abstain 0 (0%)

  From Steve Bailey

  I agree with the analysis and recommendation.  If this issue is as
  "hot" as unary reduction, then let's also add this to the 200x "fast
  lane" issues.

  From Jim Lewis

  With respect to CP-009, when CP-007 and CP-008 get implemented,
  there will need to be a corresponding to_string of some type in
  std_logic_textio.  I would like this function made visible the
  package declaration.  Hence we would have something that is
  effectively the same as 'image.  I have a similar request for 200X.
  This suits me better from a usability standpoint anyway: with
  to_string:

    write(OUTPUT, to_str(My_slv) & CR) ;

  with 'image it is more verbose:

    write(OUTPUT, std_logic_vector'image(My_slv) & CR) ;