[Haskell-cafe] parsec get line number of lexems

Olivier Duhart olivier.duhart at gmail.com
Mon Jul 18 14:28:46 UTC 2016

thanks for your answer, exactly what I was looking for. Now I have parsers 
like this :

ifStmt :: Parser Stmt
ifStmt =
  do reserved "if"
     *pos <- getPosition*
     cond  <- expression
     reserved "then"
     stmt1 <- statement
     reserved "else"
     stmt2 <- statement
     return $ If cond stmt1 stmt2 *pos*

My AST is not fully "positioned" though as I don't get how to add position 
in expression (more precisely on operators).
I am using the buildExpressionParser to build expression parsers so I have

operators = [ [Prefix (reservedOp "-"   >> return (Neg ))          ]
             , [Infix  (reservedOp "*"   >> return (Binary Multiply)) 
AssocLeft, .....

And I dont known how to tell parsec to add a SourcePos to my operators.

Any suggestion please ?

Le dimanche 17 juillet 2016 19:09:32 UTC+2, Francesco Ariis a écrit :
> On Sun, Jul 17, 2016 at 09:50:27AM -0700, Olivier Duhart wrote:
> > is ther a way to get the line numbers at parsers level?
> Hi Olivier,
>     maybe you are looking for
> http://hackage.haskell.org/package/parsec-3.1.11/docs/Text-Parsec.html#v:getPosition
> (which is very simple and used mainly for error reporting) or you could
> just keep track of `currLine` into a State of your choice (the 's' in
> ParsecT s ...).
> Does that help?
> -F
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