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<p class="MsoNormal">I'm trying to give the user the possibility to jump to the definition of a symbol in the source file. You click on the name of a function and you're send to the module where it's defined. So I have an AST, and somewhere down the line I
 have an Id object representing that function call. Then I just use <span style="font-family:&quot;Courier New&quot;">
ppr&nbsp;alwaysQualify id</span> to get the fully qualified name of the function, and I can then use the module name to retrieve the source file etc.<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">No, no, don&#8217;t do this.&nbsp; The ppr alwaysQualify thing tries hard to display the thing *<b>in the current scope</b>*.&nbsp; So if you have<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; import M as N<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">it will, I think, print thing as N.f, N.g, etc, not as M.f, M.g.&nbsp; The intent is to give user-comprehensible error messages.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">What you want is to use<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; idName :: Id -&gt; Name<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nameModule_maybe :: Name -&gt; Maybe Modlue<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">The latter gives you the *<b>defining</b>* module for the Id, which is what you wanted. It returns nothing for local variables (e.g. lambda-bound).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal">This works well in cases, but not in others. It will sound silly to the gurus on the list, but it's when the function has generics that it doesn't work. So a function with a type class in its type signature will never be printed qualified.
 It kinda like makes sense because I suppose some work has been done so that it represents the function with proper types, etc., but how can I get back to the original Id? How can I get back from that unqualified Id to the qualified Id representing the function
 in the original module? I've been looking round Name and OccName and all that but I'm not sure really what I'm looking for.<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">Suppose we have&nbsp; List.sort :: Ord a =&gt; [a] -&gt; [a]. &nbsp;And the program is<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">f x = sort [x,x]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">Then, after type checking, the code looks more like this:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">f :: Ord a =&gt; a -&gt; [a]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">f = /\a. \d:Ord a.&nbsp; let &nbsp;s :: [a] -&gt; [a]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;s = List.sort a d<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; in \(x:a). s [x,x]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">Notice the local function &#8216;s&#8217;.&nbsp; (Well, its string-name is still &#8220;sort&#8221;, but it&#8217;s not the global List.sort.)&nbsp; I think you are poking on &#8216;s&#8217;.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">Happily, GHC 7 takes a simpler approach, and instead generate something more like<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">f :: Ord a =&gt; a -&gt; [a]<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:4.8pt"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">f = /\a. \d:Ord a.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;\(x:a). List.sort a d [x,x]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">So it may &#8220;just work&#8221; in GHC 7.&nbsp;
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><br>
Hope this helps.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D">Good luck with EclipseFP.&nbsp; We need a good Haskell IDE.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:&quot;Verdana&quot;,&quot;sans-serif&quot;;color:#1F497D"><br>
Simon<o:p></o:p></span></p>
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