View Source Funx.Monad.Effect.Right (funx v0.1.7)

Represents the Right variant of the Effect monad, used to model a successful computation in an asynchronous context.

This module implements the following protocols:

Funx.Monad: Implements the bind/2, map/2, and ap/2 functions to handle monadic operations within an effectful, lazy execution context.
String.Chars: Provides a to_string/1 function to represent Right values as strings.

The Right effect allows the computation to proceed with successful values, supporting lazy, asynchronous tasks and capturing execution context through the Effect.Context struct.

Reader Operations

ask/1 – Returns the environment passed to run/2 as a Right.
asks/2 – Applies a function to the environment passed to run/2, wrapping the result in a Right.

Summary

Types

t()

t(right)

Represents an asynchronous computation that produces a Right value.

Functions

ask(opts_or_context \\ [])

Returns a Funx.Monad.Effect.Right that yields the environment passed to Funx.Monad.Effect.run/2.

asks(f, opts_or_context \\ [])

Returns a Funx.Monad.Effect.Right that applies the given function to the environment passed to Funx.Monad.Effect.run/2.

pure(value, opts_or_context \\ [])

Creates a new Right effect.

Types

t()

@type t() :: t(term())

t(right)

@type t(right) :: %Funx.Monad.Effect.Right{
  context: Funx.Monad.Effect.Context.t(),
  effect: (term() -> Task.t()) | (term() -> Funx.Monad.Either.Right.t(right))
}

Represents an asynchronous computation that produces a Right value.

The effect function is typically a deferred task that takes an environment and returns a Task. Since Elixir does not support parameterized Task.t() types, the return type is described as a union: either a Task.t() or a plain Either.Right.t(right) for testability and flexibility.

The context carries telemetry and trace information used during execution.

Functions

ask(opts_or_context \\ [])

@spec ask(Funx.Monad.Effect.Context.opts_or_context()) :: t(env) when env: term()

Returns a Funx.Monad.Effect.Right that yields the environment passed to Funx.Monad.Effect.run/2.

This is the Reader monad's equivalent of ask, giving access to the entire injected environment for further computation.

Example

iex> Funx.Monad.Effect.Right.ask()
...> |> Funx.Monad.map(& &1[:user])
...> |> Funx.Monad.Effect.run(%{user: "alice"})
%Funx.Monad.Either.Right{right: "alice"}

asks(f, opts_or_context \\ [])

@spec asks(
  (Funx.Monad.Effect.Context.t() -> result),
  Funx.Monad.Effect.Context.opts_or_context()
) ::
  t(result)
when result: term()

Returns a Funx.Monad.Effect.Right that applies the given function to the environment passed to Funx.Monad.Effect.run/2.

This allows extracting a value from the environment and using it in an effectful computation, following the Reader pattern.

Example

iex> Funx.Monad.Effect.Right.asks(fn env -> env[:user] end)
...> |> Funx.Monad.bind(fn user -> Funx.Monad.Effect.right(user) end)
...> |> Funx.Monad.Effect.run(%{user: "alice"})
%Funx.Monad.Either.Right{right: "alice"}

pure(value, opts_or_context \\ [])

@spec pure(right, Funx.Monad.Effect.Context.opts_or_context()) :: t(right)
when right: term()

Creates a new Right effect.

The pure/2 function wraps a value in the Right effect monad, representing an asynchronous success.

Examples

iex> effect = Funx.Monad.Effect.Right.pure("success")
iex> Funx.Monad.Effect.run(effect)
%Funx.Monad.Either.Right{right: "success"}