Dear list,
I am trying to make a compiler and we are having a hard time getting Alex to
work. We have succeded to work out Alex using older version, but with the the
2.2 version we keep getting this error and we havent been able to figure it out.
So this is our tokens definition:
{
module Lexico where
import Alex
}
%wrapper "posn"
$digit = 0-9 -- digits
$alpha = [a-zA-Z] -- alphabetic characters
tokens :-
$white+ ; --Los espacios en blanco los omito
\/\/.* ; --Lo que venga después de dos barras
omito
\/\*.*\*\/ ; --Lo que está entre las barras de
comentario omito
$digit+ { \p s -> TokenEntero p (read s) }
\' [$alpha $digit \_]* \' { \p s -> TokenString p (read s)}
[$digit]+\.[$digit]+ { \p s -> TokenDouble p (read s) }
$alpha [$alpha $digit \_]* { \p s -> TokenVar p (read s) }
And when we call the alexScanTokens "hello" we get this error:
[TokenVar (AlexPn 0 1 1) "*** Exception: Prelude.read: no parse
So we are concerned about the "TokenVar p (read s)" . Would that be the way to
read a string?
We just get this error with TokenVar and TokenString, whenever we call the
function like: alexScanTokens 19 , for instance we dont get any problems and
the token 19 is recognized ok.
Please, any ideas on what am i doing wrong????????
regards,
L
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