Hi, I'm trying to write a function that finds out the week day using the Zeller congruence (http://en.wikipedia.org/wiki/Zeller's_congruence). However, ghc complains about: parse error on input `=' at the "if m <= 2 then " line. I believe this is some sort of layout error. Can someone point out what I am doing wrong? Here's the code: data DiaSemana = Lunes | Martes | Miercoles | Jueves | Viernes | Sabado | Domingo deriving (Show, Eq, Ord, Enum) diaDeSemana d m a = toEnum num :: DiaSemana where num = zeller x y z zeller x y z = (700 + (26 * x - 2) `div` 10 + d + y + y `div` 4 + z `div` 4 - 2 * z) `mod` 7 if m <= 2 then x = m + 10 y = (a - 1) `mod` 100 z = (a-1) 'div' 100 else x = m - 2 y = a `mod` 100 z = a `div` 100