Hoogle Search

Within LTS Haskell 24.64 (ghc-9.10.3)

Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.

Exact lookup

1. void :: Monad m => m a -> m ()

   network-transport	Network.Transport.Internal

   Not all versions of "base" export void

2. traceId :: String -> String

   relude	Relude.Debug

   Warning: traceId remains in code

3. traceShowId :: Show a => a -> a

   relude	Relude.Debug

   Warning: traceShowId remains in code

4. void :: Functor f => f a -> f ()

   relude	Relude.Functor.Reexport

   void value discards or ignores the result of evaluation, such as the return value of an IO action.

   Examples

   Replace the contents of a Maybe Int with unit:

   >>> void Nothing
   Nothing
   

   >>> void (Just 3)
   Just ()
   

   Replace the contents of an Either Int Int with unit, resulting in an Either Int ():

   >>> void (Left 8675309)
   Left 8675309
   

   >>> void (Right 8675309)
   Right ()
   

   Replace every element of a list with unit:

   >>> void [1,2,3]
   [(),(),()]
   

   Replace the second element of a pair with unit:

   >>> void (1,2)
   (1,())
   

   Discard the result of an IO action:

   >>> mapM print [1,2]
   1
   2
   [(),()]
   

   >>> void $ mapM print [1,2]
   1
   2
   

5. module Relude.Monoid

   Reexports functions to work with monoids plus adds extra useful functions.

6. class Semigroup a => Monoid a

   relude	Relude.Monoid

   The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following:

   • Right identity x <> mempty = x
   • Left identity mempty <> x = x
   • Associativity x <> (y <> z) = (x <> y) <> z (Semigroup law)
   • Concatenation mconcat = foldr (<>) mempty
   You can alternatively define mconcat instead of mempty, in which case the laws are:
   • Unit mconcat (pure x) = x
   • Multiplication mconcat (join xss) = mconcat (fmap mconcat xss)
   • Subclass mconcat (toList xs) = sconcat xs
   The method names refer to the monoid of lists under concatenation, but there are many other instances. Some types can be viewed as a monoid in more than one way, e.g. both addition and multiplication on numbers. In such cases we often define newtypes and make those instances of Monoid, e.g. Sum and Product. NOTE: Semigroup is a superclass of Monoid since base-4.11.0.0.

7. data WrappedMonoid m

   relude	Relude.Monoid

   Provide a Semigroup for an arbitrary Monoid. NOTE: This is not needed anymore since Semigroup became a superclass of Monoid in base-4.11 and this newtype be deprecated at some point in the future.

8. maybeToMonoid :: Monoid m => Maybe m -> m

   relude	Relude.Monoid

   Extracts Monoid value from Maybe returning mempty if Nothing.

   >>> maybeToMonoid (Just [1,2,3] :: Maybe [Int])
   [1,2,3]
   
   >>> maybeToMonoid (Nothing :: Maybe [Int])
   []
   

9. stimesIdempotent :: Integral b => b -> a -> a

   relude	Relude.Monoid

   This is a valid definition of stimes for an idempotent Semigroup. When x <> x = x, this definition should be preferred, because it works in <math> rather than <math>.

10. stimesIdempotentMonoid :: (Integral b, Monoid a) => b -> a -> a

    relude	Relude.Monoid

    This is a valid definition of stimes for an idempotent Monoid. When x <> x = x, this definition should be preferred, because it works in <math> rather than <math>

Page 516 of many | Previous | Next