Re: [Haskell-cafe] tokenize parser combinators and free applicatives

18 Oct 2016


      On 18/10/16 18:06, Ruben Astudillo wrote:
...
-- Works in wrong order
    example2 :: Either ParseError String
    example2 = parse (down query) "" "hi number 5"
      where
        query = liftAp (many letter)
                *> liftAp (many letter)
                *> liftAp (many digit)
I got it! I had to use the `runAp` combinator that the `free` package
offered. Changing to this version, of the function above in the previous
code, makes it work as intend. Sorry for bothering you!

    example2 :: Either ParseError String
    example2 = parse (runAp (\f -> f <* skipMany space) query) "" "hi
number 5"
      where
        query = liftAp (many letter)
                *> liftAp (many letter)
                *> liftAp (many digit)

-- 
-- Ruben