[Hat] Possible bug with left section expressions

[Olaf Chitil]

Dear Nikolaos,

indeed you are right that this is a bug. I recently introduced it when 
extending the position information in nhc98 and hat.
I just committed a fix to cvs which you can obtain easily with cvs update.

Thank you very much for the clear bug report,
Olaf


Nikolaos S. Papaspyrou wrote:

>
> Hello,
>
> I just checked out the latest Hat sources from the CVS.  After
> successful compilation and installation, I think I have a bug
> at hand, in the treatment of left section expressions, e.g. (2+).
>
> A very simple program that generates the bug (let's call the
> file hattest.hs):
>
>    generator = ("Hello " ++) . ("world!" ++)
>    main        = putStrLn (generator "")
>
> Here's what I get:
>
>    formal:~/foo> hmake -hat hattest
>    hat-trans  hattest.hs
>
>    Fail: mergePos 1:23-1:24 1:14-1:21
>
> As I understand it, (1:23-1:24) is the first "++" and 1:14-1:21
> is the string "Hello ".  The left section is (correctly) converted
> to the application:
>
>    (++) "Hello "
>
> but then possitions of the two subexpressions come the wrong way
> and mergePos complains.
>
> I know it can be fixed by writing the expression above instead of
> the left section, but (as this occurs in all Show instances several
> times) I think it is not an acceptable solution.
>
> Am I missing something?  If not, could somebody fix it?
>
> Thank you in advance,
> Nikos.
>
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Nikolaos S. Papaspyrou                      | Tel:  +30-210-7723393
> National Technical University of Athens     | Home: +30-210-7524801
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