[Haskell-beginners] Parse string with optional entries [Parsec]
Antoine Latter
aslatter at gmail.com
Mon Aug 8 17:17:16 CEST 2011
On Mon, Aug 8, 2011 at 9:44 AM, <Stefan.Lukasser-EE at infineon.com> wrote:
> Ah, thanks. The next step would then be to replace empty strings with Nothing, and the others with
> Just Value
>
> I forgot to mention that the values are Double.
> I tried the following:
>
> numberP :: Parser Double -- From RWH
> numberP = do
> s <- getInput
> case readSigned readFloat s of
> [(n, s')] -> n <$ setInput s'
> _ -> empty
> <?> "number"
>
> valueP :: Parser [Double]
> valueP = do
> (many numberP) `sepBy` (char '\t')
> <?> "value list"
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