<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:D="DAV:" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:wf="http://schemas.microsoft.com/sharepoint/soap/workflow/" xmlns:mver="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:mrels="http://schemas.openxmlformats.org/package/2006/relationships" xmlns:ex12t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:ex12m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:Z="urn:schemas-microsoft-com:" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page Section1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-GB link=blue vlink=purple>
<div class=Section1>
<div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'>
<div>
<p class=MsoNormal style='margin-bottom:12.0pt'>I understand that with the
proposed base package breakup [1], SYB will be moved to a separate package. But
I still don't know how this will reflect on the development of the library. In
particular:<br>
<br>
1) Where is the source code going to be hosted? Here in Utrecht we currently
have a repository with several (cabalized) generic programming libraries, SYB
included. But maybe SYB will stay in the same repository as GHC?<span
style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>I don’t think it
matters too much where it’s hosted. For us it might be convenient if it
was on darcs.haskell.org because it reduces the number of ways in which you can
get stuck. But servers are fairly reliable so this probably isn’t very
important.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><br>
2) Can development proceed independently of GHC, i.e. can a new version of SYB
be released without a new version of GHC?<span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Yes, I think that independent
development is part of the goal. The easiest way to achieve this is for SYB *<b>not</b>*
to be a GHC “core package”. That is, not needed to build GHC (or
GHCi, or the GHC library). Then it’s “just a library” like
GtK or LibCurl, and you can upgrade it whenever you like.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>It’s more complicated
if it’s a core package. For example, if the GHC API uses SYB to implement
something, then package “ghc-6.9” will depend on package “SYB-2.7”,
and while you can also have SYB-3.2 installed the ghc-6.9 package will still
use the “SYB-2.7”.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><br>
3) How does the separation affect the automatic instance deriving mechanism?<br>
<br>
<span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>It think it’d make
sense for the classes Data and Typable themselves to remain in a “core
package”, precisely because the deriving mechanism generates code for
them. If you change the method signatures, the code has to change, for
example. But all the library code layered on top can be in the SYB package.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>I hope I have this right!<o:p></o:p></span></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Simon<o:p></o:p></span></p>
</div>
</div>
</div>
</body>
</html>