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<P><SPAN LANG="es"><FONT FACE="Times New Roman">Hi,<BR>
In Prelude.hs you can find the definition<BR>
enumFrom x = map toEnum [ fromEnum x ..]<BR>
Load a file.hs of just one line:<BR>
data TBool = Falsity | Undefined |Truth deriving (Enum, Show)<BR>
Then, I evaluate<BR>
enumFrom Falsity<BR>
and, as expected, it gives<BR>
[Falsity,Undefined,Truth]<BR>
However, the expression<BR>
map toEnum [ fromEnum Falsity ..]<BR>
gives first an ambiguity problem and then the problem I expected </FONT></SPAN>
<BR><SPAN LANG="es"><FONT FACE="Times New Roman">Main> map toEnum [ fromEnum Falsity ..]<BR>
ERROR - Unresolved overloading<BR>
*** Type : Enum a => [a]<BR>
*** Expression : map toEnum (enumFrom (fromEnum Falsity)) </FONT></SPAN>
<BR><SPAN LANG="es"><FONT FACE="Times New Roman">Main> map toEnum [ fromEnum Falsity ..]::[TBool]<BR>
[Falsity,Undefined,Truth,<BR>
Program error: {_toEnum TBool_Falsity 3}<BR>
(98 reductions, 301 cells) </FONT></SPAN>
<BR><SPAN LANG="es"><FONT FACE="Times New Roman">Why the function enumFrom works perfectly in spite of its erroneous definition?<BR>
Thanks in advance,<BR>
Paqui </FONT></SPAN>
<BR><SPAN LANG="es"><FONT COLOR="#0000FF" FACE="Times New Roman">P.D. </FONT></SPAN>
<BR><SPAN LANG="es"><FONT COLOR="#000000" FACE="Times New Roman">I am using the<BR>
|| || || || || || ||__ Hugs 98: Based on the Haskell 98 standard<BR>
||___|| ||__|| ||__|| __|| Copyright (c) 1994-2002<BR>
||---|| ___|| World Wide Web:</FONT> </SPAN><A HREF="http://haskell.org/hugs"><SPAN LANG="es"><U></U><U><FONT COLOR="#0000FF" FACE="Times New Roman">http://haskell.org/hugs</FONT></U></SPAN></A><SPAN LANG="es"><FONT COLOR="#000000" FACE="Times New Roman"><BR>
|| || Report bugs to: hugs-bugs@haskell.org<BR>
|| || Version: Nov 2002</FONT> </SPAN>
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<P><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">--------------------------------- </FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Paqui Lucio </FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Dpto de LSI </FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Facultad de Informática</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Paseo Manuel de Lardizabal, 1</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">20080-San Sebastián</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">SPAIN</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">---------------------------------</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">e-mail: paqui.lucio@ehu.es</FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Tfn: (+34) (9)43 015049 </FONT></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">Fax: (+34) (9)43 015590</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">Web: </FONT></SPAN><A HREF="http://www.sc.ehu.es/paqui"><SPAN LANG="en-gb"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Courier New">http://www.sc.ehu.es/paqui</FONT></U></SPAN></A><SPAN LANG="en-gb"></SPAN>
<BR><SPAN LANG="es"><FONT SIZE=2 FACE="Courier New">---------------------------------</FONT></SPAN><SPAN LANG="es"></SPAN>
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