(UPDATED)
I have made an interface using a Free Monad to a generic data store. I want to place the specific interpreter (:: DataStore a -> IO a) chosen by the user at run time into a state monad along with some other information. I cannot seem to…
I want to use Reader in my DSL that I created using a Free monad.
I notice that there is a instance of MonadReader for Free here:
https://hackage.haskell.org/package/free-4.12.1/docs/src/Control-Monad-Free.html#line-264
If I try to call ask inside…
This is a follow up to Is it possible to extend free monad interpreters? or better the reverse.
I recently revisited the project that the previous question stemmed from. This time I try to parse the file into the data structure.
Problem is that I…
I have a ConnectionIO[Option[Int]] and map over the Option to produce a ConnectionIO[Option[String]] with a query the Some[Int] otherwise keep the Nones. I was able to do this with aforcomprehension and amatch`:
def findWidgetByOwner(name: String):…
I've been spending time lately to grasp FP concepts and especially the free monad. I think I understand the idea behind free monads quite well, but a question arose.
I've been using Doobie for a bit which is built on top of free monads. For me, it…
I'm playing with free monads in Haskell and I got stuck with defining the functions that lift the functor constructors in the Free monad.
I have the AppF functor as a sum of several functors, each representing an effect. One of these functors is…
I am trying to learn how to use FreeMonads to implement interpreters for my services.
Suppose I have
sealed trait ServiceAction[T] extends Product with Serializable
case class ConsumeCommand(cmd: AccruePoints) extends…
module Main where
data Toy b next =
Output b next
| Bell next
| Done
data FixE f e = Fix (f (FixE f e)) | Throw e
-- The working monadic function
catch :: (Functor f) => FixE f e1 -> (e1 -> FixE f e2) -> FixE f e2
catch (Fix x) f = Fix…
Suppose I need to add generate an RSS/Atom feed for a blog site. I am thinking about the "Feed Monad Interpreter" pattern. That is, I would define a DSL with primitives Blog and BlogPost, a Free monad, which is just a tree of these primitives, and…
I'm trying to get my head around monads and Cats. Following some examples (e.g.cats) I wrote the code like below. But can't figure out how to make compiler to do what I need and to compile, actually.
import cats.Id
import cats.free.Free
import…
