[fitsbits] reopening of Public Comment Period on the CONTINUE convention

[Tom McGlynn (NASA/GSFC Code 660.1)]

I don't see any significant issues with this proposal.  Tiny nits below.
     Tom McGlynn


    - I don't like the difference in the requirement that there be a 
space before the / in comments
      in CONTINUE versus a recommendation that there be such a space in 
other keywords.  It seems
     cleaner to have the same rules both places.  This kind if niggling 
difference is a trap waiting to cause problems to some
     poor soul in the future.  Given that we can't invalidate existing 
FITS files, I prefer to simply
     recommend the space both places (not really sure why we make this 
recommendation anyway).

   - Given that there is some reference to the historical background of 
this convention I think it might
     be appropriate to note that this convention is now to be applied 
regardless of the existence of
     a LONGSTRN key in the header.  Maybe the reference in the appendix 
is enough...

   - It would be nice if there were some discussion of the value of the 
comment section when there
     are multiple comments.  E.g., what is the value of the comment 
associated with KEY in the following

KEY = 'abc&' ./ Comment1.
CONTINUE 'def&' /          Ten spaces after /.
CONTINUE '' / More...

Do I preserve spaces after the /, are they completely insignificant, 
should I simply put a single space between lines and ignore leading
and trailing spaces otherwise.  I could imagine:
    ' Comment1          Ten spaces after /. More ...'
or
   'Comment1Ten spaces after/.More ...'
or
   'Comment1. Ten spaces after /. More ...'

I think I'd prefer the last.  [Leading and trailing spaces 
insignificant, but all lines but the first preceded by space.]  I 
wouldn't mandate this but some statement indicating preferred practice 
would make sense.

    - Not  clear to me what

KEY = 'abc&'
CONTINUE

is supposed to mean.  Is the CONTINUE keyword conforming so that KEY=abc 
or non-conforming (no string in it) so the ampersand is significant?  I 
think I prefer the former, but not obvious what 'conforming' means.

    - Do we want to dis/encourage this convention to be used when the 
string value would fit, but we have a long comment?  E.g.,
KEY = 'short&' / The start of a very, very, very...
CONTINUE '&' / very, very, very, ...
CONTINUE '&' / very, very, very, ...
CONTINUE '' / long comment

If this is a practice we want to encourage, then the limitation of 
CONTINUE to after string keywords makes less sense.


Lucio Chiappetti wrote:
> ANNOUNCEMENT:  START OF FORMAL PUBLIC COMMENT PERIOD
>
> This is to announce the official reopening of a formal Public Comment 
> Period on the incorporation of the long string keyword convention (aka 
> CONTINUE) in the FITS Standard.
>
> A previous PCP was held in June-July (started on 19 Jun 2015).
>
> We are now re-opening the Public Comment Period to collect comments on 
> the modified text of the various conventions.
>
> The fourth convention of the list, to be discussed NOW defines the use 
> of the CONTINUE keyword to allow string-valued keywords to have values 
> longer than 68 char.
>
> An updated draft text (sentences hilighted in brown) is available at 
> http://sax.iasf-milano.inaf.it/~lucio/FITS/Conventions/continue-rev.pdf
>
> - minor rewording in/and final sentence of 4.1.1
> - change title of section 4.2.1.1 (which describes the "traditional"
>   Single record string keyword) and last sentence thereof
> - new section 4.2.1.2
> - cross-reference sentence in 4.4.2.4
>
> The differences w.r.t. the earlier version, requested during the 
> previous PCP, consist in
>
> - the above change of title
> - the restriction for excluding just a few keywords from using the
>   continuation convention has been removed
> - a way to extend the comment field over multiple header records is
>   described
> - rewording on orphaned CONTINUE keywords
>
> Considering previous discussion already had, I am reopening the PCP 
> for TWO WEEKS (in order to speed up the cumulative process dealing 
> with all conventions), but this can be extended if requested and 
> motivated.
>
> - as usual appendices C and H.3 (not shown) will be updated 
> accordingly at
>    the end of the entire convention incorporation procedure
>
> Please review the text carefully and post any comments, criticisms, or
> suggestions on the FITSBITS mailing list.
>
> Supporting material for the PREVIOUS public comment period 
> announcement can be retrieved from the FITSBITS archives starting from 
> https://listmgr.nrao.edu/pipermail/fitsbits/2015-June/002616.html
>
> ==================================================================
>
> The reopened Public Comment Period starts today 26 February 2016 and 
> will last until 13 March 2016, unless extensions are requested and 
> motivated.
>