<div dir="ltr"><div><div><div><div><div>OK, it's 22 years, not a quarter century:<br><a href="http://heasarc.nasa.gov/docs/heasarc/ofwg/docs/ofwg_recomm/r13.html">http://heasarc.nasa.gov/docs/heasarc/ofwg/docs/ofwg_recomm/r13.html</a><br></div>But the convention as written has been used in millions of files since then.<br></div>As Peter said, it may, in hindsight, not be the most beautiful solution (and<br></div>if we were designing it today, we might have chosen your proposal), but it<br></div>works, and has been working for 20+ years, so let's just live with it.<br><br></div><div>Cheers,<br></div><div><br></div> - Arnold<br></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr">-------------------------------------------------------------------------------------------------------------<br>Arnold H. Rots Chandra X-ray Science Center<br>Smithsonian Astrophysical Observatory tel: +1 617 496 7701<br>60 Garden Street, MS 67 fax: +1 617 495 7356<br>Cambridge, MA 02138 <a href="mailto:arots@cfa.harvard.edu" target="_blank">arots@cfa.harvard.edu</a><br>USA <a href="http://hea-www.harvard.edu/~arots/" target="_blank">http://hea-www.harvard.edu/~arots/</a><br>--------------------------------------------------------------------------------------------------------------<br><br></div></div></div>
<br><div class="gmail_quote">On Thu, Mar 10, 2016 at 8:59 AM, Demitri Muna <span dir="ltr"><<a href="mailto:demitri.muna@gmail.com" target="_blank">demitri.muna@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Hi Peter,<div><br><div><span class=""><div><div>On Mar 9, 2016, at 4:13 AM, Peter Weilbacher <<a href="mailto:pweilbacher@aip.de" target="_blank">pweilbacher@aip.de</a>> wrote:</div><br></div><blockquote type="cite"><div><div><blockquote type="cite" style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">There is a standard here that is used in virtually every (every)<br>computer language - continuation or concatenation characters are<br>located outside of the string being quoted.<br></blockquote><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">But we are not discussing a computer language here, but a file format.</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"></div></div></blockquote><div><br></div></span><div>I mentioned it as the convention will already be familiar to people. But whether it’s a file format or a computer language is irrelevant; the question what is easier to parse and/or read, first by a human and second by a computer. When one sees a line end with an ampersand and a single quote, the current proposal says “this might be a continuation character, or it might not.” When virtually every computer language agrees on a certain syntax, it’s worth paying attention to. Can anyone point to a counterexample where the continuation character is contained within a quoted string anywhere?</div><span class=""><br><blockquote type="cite"><div><div><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">I don't think that the FITS Standard allows to have anything between the</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">value and the '/' that starts the comment. At least that's how I</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">understand Section 4.1.1 and Appendix A. So having the continue</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">character outside the string literals would make a very fundamental</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">change to the FITS format. And quite hard on every FITS header parser.</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"></div></div></blockquote><div><br></div></span><div>The current proposal specifically modifies Section 4.1.1, so that is what is under discussion. Given this:</div><div><br></div><div>STRKEY = 'This keyword value is continued&'</div><div>CONTINUE ' over multiple keyword records.'</div><div><br></div><div>or this:</div><div><br></div><div><div>STRKEY = 'This keyword value is continued' &</div><div>CONTINUE ' over multiple keyword records.'</div><div><br></div></div><div>an existing parser would treat the ampersand as part of the value and see no comment. I don’t see how this is a fundamental change or how it will break existing parsers. Can you provide an example where this would be a problem? You would never have this, for example:</div><div><br></div><div>STRKEY = 'string' & / comment</div><div><br></div><div>This seems to be the edge case, where again the ampersand is not between the '/' and the comment, which is still not a problem:</div><div><br></div><div>STRKEY = 'some string that ends here but is followed by a comment' &</div><div>CONTINUE '' / comment here </div><span class=""><div><br></div><blockquote type="cite"><div><div><blockquote type="cite" style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">If the motivation is to turn into a standard something that someone<br>else decided ad hoc to do, then I’d ask if this really is the best way<br>to define standards? The fact that one institute did something doesn’t<br>necessarily make it the best idea, and in this case I really don’t<br>think it is.<br></blockquote><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">The discussions about the CONTINUE discussion predate my time in</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">astronomy as well, but if you read up on the convention's history, you</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">will find quite a few messages to this list from 1993 and 94. So it was</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">not decided "ad-hoc" at all, and not by one institute, either. (I think</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">this is true for all the conventions that currently exist.)</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"></div></div></blockquote><div><br></div></span><div>The oldest message on the web archive only goes back to March 1996 (which I note with amusement contains a message with the subject "[ANN] New FITS viewer for the Macintosh"). I mean ad hoc in the sense that it wasn't part of the format. But I think the argument that it was discussed a quarter century ago isn't a strong one; I am pointing out very specific reasons why this is not the best idea.</div><span class=""><br><blockquote type="cite"><div><div><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">I agree that this is not the most beautiful way to create FITS headers.</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">But since the motivation here is rather to have an incremental</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">improvement that works (we know, because it has seen usage for 20+</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">years) instead of reinventing the FITS format, I agree with the</span><br style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:14px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">proposal.</span></div></div></blockquote></span></div><div><br></div><div>I think this is a very important point. There has been a lot of discussion about file formats and pretty wide dissatisfaction with FITS. There's no question it's showing its age. I think it would be one thing if there was a commitment to properly addressing the real concerns with a proper FITS v2.0 versus incremental patching. The past should guide the future, not constrain it.</div><div><br></div><div>Cheers,</div>Demitri</div><div><br><div>
<div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><span class=""><div style="color:rgb(0,0,0);font-family:'Gill Sans';font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">_________________________________________<br>Demitri Muna<br><a href="http://muna.com" target="_blank">http://muna.com</a></div></span><div style="color:rgb(0,0,0);font-family:'Gill Sans';font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><br>Department of Astronomy<br>Le Ohio State University<br><br></div><span class=""><div style="color:rgb(0,0,0);font-family:'Gill Sans';font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">My Projects:</div><div style="color:rgb(0,0,0);font-family:'Gill Sans';font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><a href="http://nightlightapp.io" target="_blank">http://nightlightapp.io</a><br><a href="http://trillianverse.org" target="_blank">http://trillianverse.org</a></div><div style="color:rgb(0,0,0);font-family:'Gill Sans';font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word"><a href="http://scicoder.org" target="_blank">http://scicoder.org</a><br><br><br></div></span></div></div></div></div></div></div>
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