Functional Programming Synonyms

So you enjoy FP, but every time you stumble upon a tutorial written for a specific language or library, everything seems new all over again. Or is it?

In fact it often relies on the same foundations, but different naming are applied to these concepts in Haskell, Scala, F#, Fantasy Land…

I'll try to list common synonyms on this page.


Maybe, Option

Either, Result


Just, Some

Nothing, None

Left, Ok

Right, Error


all, every

any, some

map, fmap, lift, select, collect, transform, <$>,

filter, select

find, detect

reduce, fold, inject

pure, return, point, of, wrap, unit, yield

ap, apply, <*>

bind, chain, flatMap, then, >>=