title: What does t0,t1,t2 and a0 mean in Haskell?
body: <p>I have been coding in Haskell for couple of weeks now and I keep on seeing errors with t0,t1,t2 and a0. I'm wondering, do they have any in particular meaning or they are just variables? I am asking because I would like to understand better the errors that the compiler spits at me.</p>