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<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'>It’s expected but unfortunate.
Template Haskell runs *<b><span style='font-weight:bold'>during</span></b>*
type checking. So when you reify a local type, it may not yet be fully worked
out. In this case it would be worse if you said<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'> let a=10 <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'> in ( $(…reify ‘a…),
a+1::Int )<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'>Here it’s “clear” that
a has type Int, but it won’t be clear to Template Haskell until after it’s
typechecked the whole expression. But it has to run the splice before that! <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'>That’s a shortcoming I don’t
know how to solve at the moment.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'>Simon<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Verdana><span style='font-size:
10.0pt;font-family:Verdana;color:blue'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>
template-haskell-bounces@haskell.org
[mailto:template-haskell-bounces@haskell.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Oleg Mürk<br>
<b><span style='font-weight:bold'>Sent:</span></b> 23 April 2006 22:53<br>
<b><span style='font-weight:bold'>To:</span></b> template-haskell@haskell.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Template-haskell] Type
inference</span></font><span lang=EN-US><o:p></o:p></span></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hello,<br>
<br>
I have the following problem. I'd like to infer types of local bindings using
'reify':<br>
------------------------------------<br>
testValue = <br>
let<br>
a = 10<br>
in<br>
$(do<br>
VarI _ t _ _ <-
reify 'a<br>
lift (pprint t)<br>
)<br>
-------------------------------------<br>
But this code prints only:<br>
-------------------------------------<br>
*Debug> testValue<br>
"t_0"<br>
-------------------------------------<br>
Is this intended behavior? Are there any workarounds? <br>
Things work fine if symbol is defined in another module.<br>
I do realise that in general $(...) may add additional constraints on local
variables.<br>
<br>
<st1:place w:st="on">OM</st1:place><o:p></o:p></span></font></p>
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