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Akhilesh Srikanth akhileshs

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@akhileshs
akhileshs / lc_study_prep.md
Last active November 6, 2025 20:09
lc_study_prep
@akhileshs
akhileshs / combinator.scala
Created February 23, 2018 07:07
@ def id[A](x: A): A = x
defined function id
@ def k[A, B](x: A, y: B): A = x
defined function k
@ def a[A, B](f: A => B, x: A): B = f(x)
defined function a
@ a((x: Int) => x + 1, 1)
@akhileshs
akhileshs / profunctor.hs
Created April 29, 2017 18:42
import Control.Monad
class Profunctor p where
dimap :: (a -> b) -> (c -> d) -> p b c -> p a d
-- lmap :: (a -> b) -> p b c -> p a c
-- rmap :: (c -> d) -> p b c -> p b d
instance Profunctor (->) where
-- dimap :: (a -> b) -> (c -> d) -> (->) b c -> (->) a d
@akhileshs
akhileshs / contravariant.hs
Created April 29, 2017 18:32
class Contravariant f where
fmap :: (b -> a) -> f a -> f b
newtype Predicate a = Predicate { runPredicate :: a -> Bool }
instance Contravariant Predicate where
fmap f (Predicate a) = Predicate (a . f)
data MyOrdering = LT | EQ | GT
@akhileshs
akhileshs / t1.scala
Created May 24, 2016 07:44
scala> "{ /* hello */ def foo(bar: Int) = bar }".parse[Term].get
res0: scala.meta.Term = { /* hello */ def foo(bar: Int) = bar }
scala> res0 transform { case q"bar" => q"baz" }
x.origin: Parsed(Input.String("{ /* hello */ def foo(bar: Int) = bar }"),Scala211,[18..21) in Input.String("{ /* hello */ def foo(bar: Int) = bar }"))
x : foo
x.origin: Transformed(bar)
x : baz
@akhileshs
akhileshs / trialtypelambdas.scala
Created May 7, 2016 16:43
scala> type Foo[A, B] = Map[A, B]
defined type alias Foo
scala> type World[M[_]] = M[Int]
warning: there was one feature warning; re-run with -feature for details
defined type alias World
scala> type X[A] = World[({ type M[A] = Foo[String, A] })#M]
defined type alias X
@akhileshs
akhileshs / trial1.hs
Created April 16, 2016 11:35
{-# LANGUAGE RankNTypes #-}
module F where
data User = User { name :: String, age :: Int } deriving Show
data Project = Project { owner :: User } deriving Show
type Lens s a = Functor f => (a -> f a) -> s -> f s
newtype Identity a = Identity { runIdentity :: a }
@akhileshs
akhileshs / free_monad.hs
Created April 5, 2016 19:55
data Toy b next =
Output b next
| Bell next
| Done
deriving (Show)
data FixE f e = Fix (f (FixE f e)) | Throw e
catch :: (Functor f) => FixE f e1 -> (e1 -> FixE f e2) -> FixE f e2
catch (Fix x) f = Fix (fmap (flip catch f) x)
@akhileshs
akhileshs / dt.scala
Last active March 5, 2016 11:17
trait Vect[Size, A]
def ++[n, m, a](v1: Vect[n, a], v2: Vect[m, a]): Vect[(n + m), a]
@akhileshs
akhileshs / sequence.hs
Created February 13, 2016 09:20
sequence :: Monad m => [m a] -> m [a]
sequence = foldr mcons (return [])
where mcons p q = p >>= \x -> q >>= \y -> return (x : y)