An Introduction to Functors in Haskell
The Functor typeclass is the first and most fundamental structure that serves as a basis for Applicative Functors and finally also for Monads. Learn about Functors, and some other concepts, like kind signatures, in the attached video clip below. I will give several examples and relate to Monoids as introduced in the previous post "An Introduction to Monoids in Haskell".
The clip doesn't contain any sound. This is quite deliberate for several reasons. You should adjust the playback speed to your needs and pause when you need to contemplate. It would be annoying and disruptive if the video included sound.
Where to go from Here
The typclass Functor is defined in Data.Functor. Its documentation is also available online. The Category Theory / Functor page in the Haskellwiki defines Functors from Mathematical point of view and contrasts to those used in Haskell.
About this Series
This is the second contribution of a series.