maikeulb

brew install llvm
ln -s "/usr/local/opt/llvm/bin/clang-format" "/usr/local/bin/clang-format"
ln -s "/usr/local/opt/llvm/bin/clang-tidy" "/usr/local/bin/clang-tidy"

use cmake file

  find_program(CLANG_TIDY_BIN clang-tidy)
 find_program(RUN_CLANG_TIDY_BIN /usr/local/Cellar/llvm/10.0.0_3/share/clang/run-clang-tidy.py)

maikeulb

-- Two datatypes
data Optional a = Some a | Empty deriving (Eq, Show)
data Or a b = A a | B b deriving (Eq, Show)

-- functor instances
instance Functor Optional where
  fmap f (Some a) = Some (f a)
  fmap _ Empty = Empty

instance Functor (Or a) where