[Haskell-beginners] warning in making instances of Functor class!

[Imants Cekusins]

Hello Abhijit

a properly formatted statement as you intended it is:

instance Functor (Pair1 m n) where
       fmap f (Pair1 (x,y,z))=Pair1 (f x,y,z)

note the indent before fmap.

without the tab,

fmap f (Pair1 (x,y,z))=Pair1 (f x,y,z)
is just a stand alone function delcaration

if you enter  instance.. line #1 but not the fmap line #2, you will
see the same warning you are seeing.

if you enter #2 but not #1, this line:
getPair1 $ fmap (*100) (Pair1 (2,3,1))
will work fine too.


basically, flush (no indent) line begins a new code block