Documentation
¶
Overview ¶
Package readerreaderioeither provides a functional programming abstraction that combines four powerful concepts: Reader, Reader, IO, and Either monads in a nested structure.
Type Parameter Ordering Convention ¶
This package follows a consistent convention for ordering type parameters in function signatures. The general rule is: R -> C -> E -> T (outer context, inner context, error, type), where:
- R: The outer Reader context/environment type
- C: The inner Reader context/environment type (for the ReaderIOEither)
- E: The Either error type
- T: The value type(s) (A, B, etc.)
However, when some type parameters can be automatically inferred by the Go compiler from function arguments, the convention is modified to minimize explicit type annotations:
Rule: Undetectable types come first, followed by detectable types, while preserving the relative order within each group (R -> C -> E -> T).
Examples:
All types detectable from first argument: MonadMap[R, C, E, A, B](fa ReaderReaderIOEither[R, C, E, A], f func(A) B) - R, C, E, A are detectable from fa - B is detectable from f - Order: R, C, E, A, B (standard order, all detectable)
Some types undetectable: FromReader[C, E, R, A](ma Reader[R, A]) ReaderReaderIOEither[R, C, E, A] - R, A are detectable from ma - C, E are undetectable (not in any argument) - Order: C, E, R, A (C, E first as undetectable, then R, A in standard order)
Multiple undetectable types: Local[C, E, A, R1, R2](f func(R2) R1) func(ReaderReaderIOEither[R1, C, E, A]) ReaderReaderIOEither[R2, C, E, A] - C, E, A are undetectable - R1, R2 are detectable from f - Order: C, E, A, R1, R2 (undetectable first, then detectable)
Functions returning Kleisli arrows: ChainReaderOptionK[R, C, A, B, E](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, B] - Canonical order would be R, C, E, A, B - E is detectable from onNone parameter - R, C, A, B are not detectable (they're in the Kleisli argument type) - Order: R, C, A, B, E (undetectable R, C, A, B first, then detectable E)
This convention allows for more ergonomic function calls:
// Without convention - need to specify all types: result := FromReader[OuterCtx, InnerCtx, error, User](readerFunc) // With convention - only specify undetectable types: result := FromReader[InnerCtx, error](readerFunc) // R and A inferred from readerFunc
The reasoning behind this approach is to reduce the number of explicit type parameters that developers need to specify when calling functions, improving code readability and reducing verbosity while maintaining type safety.
Additional examples demonstrating the convention:
FromReaderOption[R, C, A, E](onNone Lazy[E]) Kleisli[R, C, E, ReaderOption[R, A], A] - Canonical order would be R, C, E, A - E is detectable from onNone parameter - R, C, A are not detectable (they're in the return type's Kleisli) - Order: R, C, A, E (undetectable R, C, A first, then detectable E)
MapLeft[R, C, A, E1, E2](f func(E1) E2) func(ReaderReaderIOEither[R, C, E1, A]) ReaderReaderIOEither[R, C, E2, A] - Canonical order would be R, C, E1, E2, A - E1, E2 are detectable from f parameter - R, C, A are not detectable (they're in the return type) - Order: R, C, A, E1, E2 (undetectable R, C, A first, then detectable E1, E2)
Additional special cases:
- Ap[B, R, C, E, A]: B is undetectable (in function return type), so B comes first
- ChainOptionK[R, C, A, B, E]: R, C, A, B are undetectable, E is detectable from onNone
- FromReaderIO[C, E, R, A]: C, E are undetectable, R, A are detectable from ReaderIO[R, A]
All functions in this package follow this convention consistently.
Fantasy Land Specification ¶
This is a monad transformer combining:
- Reader monad: https://github.com/fantasyland/fantasy-land
- Reader monad (nested): https://github.com/fantasyland/fantasy-land
- IO monad: https://github.com/fantasyland/fantasy-land
- Either monad: https://github.com/fantasyland/fantasy-land#either
Implemented Fantasy Land algebras:
- Functor: https://github.com/fantasyland/fantasy-land#functor
- Bifunctor: https://github.com/fantasyland/fantasy-land#bifunctor
- Apply: https://github.com/fantasyland/fantasy-land#apply
- Applicative: https://github.com/fantasyland/fantasy-land#applicative
- Chain: https://github.com/fantasyland/fantasy-land#chain
- Monad: https://github.com/fantasyland/fantasy-land#monad
- Alt: https://github.com/fantasyland/fantasy-land#alt
ReaderReaderIOEither ¶
ReaderReaderIOEither[R, C, E, A] represents a computation that:
- Depends on an outer context/environment of type R (outer Reader)
- Returns a computation that depends on an inner context/environment of type C (inner Reader)
- Performs side effects (IO)
- Can fail with an error of type E or succeed with a value of type A (Either)
This is particularly useful for:
- Multi-level dependency injection patterns
- Layered architectures with different context requirements at each layer
- Composing operations that need access to multiple levels of configuration or context
- Building reusable components that can be configured at different stages
Core Operations ¶
Construction:
- Of/Right: Create a successful computation
- Left: Create a failed computation
- FromEither: Lift an Either into ReaderReaderIOEither
- FromIO: Lift an IO into ReaderReaderIOEither
- FromReader: Lift a Reader into ReaderReaderIOEither
- FromReaderIO: Lift a ReaderIO into ReaderReaderIOEither
- FromIOEither: Lift an IOEither into ReaderReaderIOEither
- FromReaderEither: Lift a ReaderEither into ReaderReaderIOEither
- FromReaderIOEither: Lift a ReaderIOEither into ReaderReaderIOEither
- FromReaderOption: Lift a ReaderOption into ReaderReaderIOEither
Transformation:
- Map: Transform the success value
- MapLeft: Transform the error value
- Chain/Bind: Sequence dependent computations
- Flatten: Flatten nested ReaderReaderIOEither
Combination:
- Ap: Apply a function in a context to a value in a context
- ApSeq: Sequential application
- ApPar: Parallel application
Error Handling:
- Alt: Choose the first successful computation
Context Access:
- Ask: Get the current outer context
- Asks: Get a value derived from the outer context
- Local: Run a computation with a modified outer context
- Read: Execute with a specific outer context
Kleisli Composition:
- ChainEitherK: Chain with Either-returning functions
- ChainReaderK: Chain with Reader-returning functions
- ChainReaderIOK: Chain with ReaderIO-returning functions
- ChainReaderEitherK: Chain with ReaderEither-returning functions
- ChainReaderOptionK: Chain with ReaderOption-returning functions
- ChainIOEitherK: Chain with IOEither-returning functions
- ChainIOK: Chain with IO-returning functions
- ChainOptionK: Chain with Option-returning functions
First/Tap Operations (execute for side effects, return original value):
- ChainFirst/Tap: Execute a computation but return the original value
- ChainFirstEitherK/TapEitherK: Tap with Either-returning functions
- ChainFirstReaderK/TapReaderK: Tap with Reader-returning functions
- ChainFirstReaderIOK/TapReaderIOK: Tap with ReaderIO-returning functions
- ChainFirstReaderEitherK/TapReaderEitherK: Tap with ReaderEither-returning functions
- ChainFirstReaderOptionK/TapReaderOptionK: Tap with ReaderOption-returning functions
- ChainFirstIOK/TapIOK: Tap with IO-returning functions
Example Usage ¶
type OuterConfig struct {
DatabaseURL string
LogLevel string
}
type InnerConfig struct {
APIKey string
Timeout time.Duration
}
// A computation that depends on both OuterConfig and InnerConfig
func fetchUser(id int) readerreaderioeither.ReaderReaderIOEither[OuterConfig, InnerConfig, error, User] {
return func(outerCfg OuterConfig) readerioeither.ReaderIOEither[InnerConfig, error, User] {
// Use outerCfg.DatabaseURL and outerCfg.LogLevel
return func(innerCfg InnerConfig) ioeither.IOEither[error, User] {
// Use innerCfg.APIKey and innerCfg.Timeout to fetch user
return func() either.Either[error, User] {
// Perform the actual IO operation
// Return either.Right(user) or either.Left(err)
}
}
}
}
// Compose operations
result := function.Pipe2(
fetchUser(123),
readerreaderioeither.Map[OuterConfig, InnerConfig, error](func(u User) string { return u.Name }),
readerreaderioeither.Chain[OuterConfig, InnerConfig, error](func(name string) readerreaderioeither.ReaderReaderIOEither[OuterConfig, InnerConfig, error, string] {
return readerreaderioeither.Of[OuterConfig, InnerConfig, error]("Hello, " + name)
}),
)
// Execute with both configs
outerConfig := OuterConfig{DatabaseURL: "postgres://...", LogLevel: "info"}
innerConfig := InnerConfig{APIKey: "secret", Timeout: 30 * time.Second}
outcome := result(outerConfig)(innerConfig)() // Returns either.Either[error, string]
Copyright (c) 2025 IBM Corp. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Index ¶
- func ChainFirstReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- func ChainLeft[R, C, EA, EB, A any](f Kleisli[R, C, EB, EA, A]) func(ReaderReaderIOEither[R, C, EA, A]) ReaderReaderIOEither[R, C, EB, A]
- func ChainOptionK[R, C, A, B, E any](onNone Lazy[E]) func(option.Kleisli[A, B]) Operator[R, C, E, A, B]
- func ChainReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, B]
- func FromOption[R, C, A, E any](onNone Lazy[E]) func(Option[A]) ReaderReaderIOEither[R, C, E, A]
- func FromPredicate[R, C, E, A any](pred func(A) bool, onFalse func(A) E) func(A) ReaderReaderIOEither[R, C, E, A]
- func Local[C, E, A, R1, R2 any](f func(R2) R1) func(ReaderReaderIOEither[R1, C, E, A]) ReaderReaderIOEither[R2, C, E, A]
- func MapLeft[R, C, A, E1, E2 any](f func(E1) E2) func(ReaderReaderIOEither[R, C, E1, A]) ReaderReaderIOEither[R, C, E2, A]
- func Read[C, E, A, R any](r R) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
- func ReadIO[C, E, A, R any](rio IO[R]) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
- func ReadIOEither[A, R, C, E any](rio IOEither[E, R]) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
- func TapReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- type Either
- type IO
- type IOEither
- type Kleisli
- type Lazy
- type Lens
- type Monoid
- func AltMonoid[R, C, E, A any](zero Lazy[ReaderReaderIOEither[R, C, E, A]]) Monoid[R, C, E, A]
- func AlternativeMonoid[R, C, E, A any](m monoid.Monoid[A]) Monoid[R, C, E, A]
- func ApplicativeMonoid[R, C, E, A any](m monoid.Monoid[A]) Monoid[R, C, E, A]
- func ApplicativeMonoidPar[R, C, E, A any](m monoid.Monoid[A]) Monoid[R, C, E, A]
- func ApplicativeMonoidSeq[R, C, E, A any](m monoid.Monoid[A]) Monoid[R, C, E, A]
- type Operator
- func After[R, C, E, A any](timestamp time.Time) Operator[R, C, E, A, A]
- func Alt[R, C, E, A any](second Lazy[ReaderReaderIOEither[R, C, E, A]]) Operator[R, C, E, A, A]
- func Ap[B, R, C, E, A any](fa ReaderReaderIOEither[R, C, E, A]) Operator[R, C, E, func(A) B, B]
- func ApEitherS[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, fa Either[E, T]) Operator[R, C, E, S1, S2]
- func ApEitherSL[R, C, E, S, T any](lens Lens[S, T], fa Either[E, T]) Operator[R, C, E, S, S]
- func ApIOEitherS[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, fa IOEither[E, T]) Operator[R, C, E, S1, S2]
- func ApIOEitherSL[R, C, E, S, T any](lens Lens[S, T], fa IOEither[E, T]) Operator[R, C, E, S, S]
- func ApIOS[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, fa IO[T]) Operator[R, C, E, S1, S2]
- func ApIOSL[R, C, E, S, T any](lens Lens[S, T], fa IO[T]) Operator[R, C, E, S, S]
- func ApReaderIOS[C, E, R, S1, S2, T any](setter func(T) func(S1) S2, fa ReaderIO[R, T]) Operator[R, C, E, S1, S2]
- func ApReaderIOSL[C, E, R, S, T any](lens Lens[S, T], fa ReaderIO[R, T]) Operator[R, C, E, S, S]
- func ApReaderS[C, E, R, S1, S2, T any](setter func(T) func(S1) S2, fa Reader[R, T]) Operator[R, C, E, S1, S2]
- func ApReaderSL[C, E, R, S, T any](lens Lens[S, T], fa Reader[R, T]) Operator[R, C, E, S, S]
- func ApS[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, fa ReaderReaderIOEither[R, C, E, T]) Operator[R, C, E, S1, S2]
- func ApSL[R, C, E, S, T any](lens Lens[S, T], fa ReaderReaderIOEither[R, C, E, T]) Operator[R, C, E, S, S]
- func Bind[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, f func(S1) ReaderReaderIOEither[R, C, E, T]) Operator[R, C, E, S1, S2]
- func BindEitherK[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, f either.Kleisli[E, S1, T]) Operator[R, C, E, S1, S2]
- func BindIOEitherK[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, f ioeither.Kleisli[E, S1, T]) Operator[R, C, E, S1, S2]
- func BindIOEitherKL[R, C, E, S, T any](lens Lens[S, T], f ioeither.Kleisli[E, T, T]) Operator[R, C, E, S, S]
- func BindIOK[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, f io.Kleisli[S1, T]) Operator[R, C, E, S1, S2]
- func BindIOKL[R, C, E, S, T any](lens Lens[S, T], f io.Kleisli[T, T]) Operator[R, C, E, S, S]
- func BindL[R, C, E, S, T any](lens Lens[S, T], f func(T) ReaderReaderIOEither[R, C, E, T]) Operator[R, C, E, S, S]
- func BindReaderIOK[C, E, R, S1, S2, T any](setter func(T) func(S1) S2, f readerio.Kleisli[R, S1, T]) Operator[R, C, E, S1, S2]
- func BindReaderIOKL[C, E, R, S, T any](lens Lens[S, T], f readerio.Kleisli[R, T, T]) Operator[R, C, E, S, S]
- func BindReaderK[C, E, R, S1, S2, T any](setter func(T) func(S1) S2, f reader.Kleisli[R, S1, T]) Operator[R, C, E, S1, S2]
- func BindReaderKL[C, E, R, S, T any](lens Lens[S, T], f reader.Kleisli[R, T, T]) Operator[R, C, E, S, S]
- func BindTo[R, C, E, S1, T any](setter func(T) S1) Operator[R, C, E, T, S1]
- func Chain[R, C, E, A, B any](f Kleisli[R, C, E, A, B]) Operator[R, C, E, A, B]
- func ChainEitherK[R, C, E, A, B any](f either.Kleisli[E, A, B]) Operator[R, C, E, A, B]
- func ChainFirst[R, C, E, A, B any](f Kleisli[R, C, E, A, B]) Operator[R, C, E, A, A]
- func ChainFirstEitherK[R, C, E, A, B any](f either.Kleisli[E, A, B]) Operator[R, C, E, A, A]
- func ChainFirstIOK[R, C, E, A, B any](f io.Kleisli[A, B]) Operator[R, C, E, A, A]
- func ChainFirstReaderEitherK[C, E, R, A, B any](f RE.Kleisli[R, E, A, B]) Operator[R, C, E, A, A]
- func ChainFirstReaderIOK[C, E, R, A, B any](f readerio.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- func ChainFirstReaderK[C, E, R, A, B any](f reader.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- func ChainIOEitherK[R, C, E, A, B any](f IOE.Kleisli[E, A, B]) Operator[R, C, E, A, B]
- func ChainIOK[R, C, E, A, B any](f io.Kleisli[A, B]) Operator[R, C, E, A, B]
- func ChainReaderEitherK[C, E, R, A, B any](f RE.Kleisli[R, E, A, B]) Operator[R, C, E, A, B]
- func ChainReaderIOK[C, E, R, A, B any](f readerio.Kleisli[R, A, B]) Operator[R, C, E, A, B]
- func ChainReaderK[C, E, R, A, B any](f reader.Kleisli[R, A, B]) Operator[R, C, E, A, B]
- func Delay[R, C, E, A any](delay time.Duration) Operator[R, C, E, A, A]
- func Flap[R, C, E, B, A any](a A) Operator[R, C, E, func(A) B, B]
- func Let[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, f func(S1) T) Operator[R, C, E, S1, S2]
- func LetL[R, C, E, S, T any](lens Lens[S, T], f func(T) T) Operator[R, C, E, S, S]
- func LetTo[R, C, E, S1, S2, T any](setter func(T) func(S1) S2, b T) Operator[R, C, E, S1, S2]
- func LetToL[R, C, E, S, T any](lens Lens[S, T], b T) Operator[R, C, E, S, S]
- func Map[R, C, E, A, B any](f func(A) B) Operator[R, C, E, A, B]
- func MapTo[R, C, E, A, B any](b B) Operator[R, C, E, A, B]
- func Tap[R, C, E, A, B any](f Kleisli[R, C, E, A, B]) Operator[R, C, E, A, A]
- func TapEitherK[R, C, E, A, B any](f either.Kleisli[E, A, B]) Operator[R, C, E, A, A]
- func TapIOK[R, C, E, A, B any](f io.Kleisli[A, B]) Operator[R, C, E, A, A]
- func TapReaderEitherK[C, E, R, A, B any](f RE.Kleisli[R, E, A, B]) Operator[R, C, E, A, A]
- func TapReaderIOK[C, E, R, A, B any](f readerio.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- func TapReaderK[C, E, R, A, B any](f reader.Kleisli[R, A, B]) Operator[R, C, E, A, A]
- type Option
- type Predicate
- type Reader
- type ReaderIO
- type ReaderIOEither
- type ReaderOption
- type ReaderReaderIOEither
- func Ask[R, C, E any]() ReaderReaderIOEither[R, C, E, R]
- func Asks[C, E, R, A any](r Reader[R, A]) ReaderReaderIOEither[R, C, E, A]
- func Bracket[R, C, E, A, B, ANY any](acquire ReaderReaderIOEither[R, C, E, A], ...) ReaderReaderIOEither[R, C, E, B]
- func Do[R, C, E, S any](empty S) ReaderReaderIOEither[R, C, E, S]
- func Flatten[R, C, E, A any](mma ReaderReaderIOEither[R, C, E, ReaderReaderIOEither[R, C, E, A]]) ReaderReaderIOEither[R, C, E, A]
- func FromEither[R, C, E, A any](t Either[E, A]) ReaderReaderIOEither[R, C, E, A]
- func FromIO[R, C, E, A any](ma IO[A]) ReaderReaderIOEither[R, C, E, A]
- func FromIOEither[R, C, E, A any](ma IOEither[E, A]) ReaderReaderIOEither[R, C, E, A]
- func FromReader[C, E, R, A any](ma Reader[R, A]) ReaderReaderIOEither[R, C, E, A]
- func FromReaderEither[R, C, E, A any](ma RE.ReaderEither[R, E, A]) ReaderReaderIOEither[R, C, E, A]
- func FromReaderIO[C, E, R, A any](ma ReaderIO[R, A]) ReaderReaderIOEither[R, C, E, A]
- func FromReaderIOEither[C, E, R, A any](ma ReaderIOEither[R, E, A]) ReaderReaderIOEither[R, C, E, A]
- func Left[R, C, A, E any](e E) ReaderReaderIOEither[R, C, E, A]
- func LeftIO[R, C, A, E any](ma IO[E]) ReaderReaderIOEither[R, C, E, A]
- func LeftReader[C, A, R, E any](ma Reader[R, E]) ReaderReaderIOEither[R, C, E, A]
- func LeftReaderIO[C, A, R, E any](me ReaderIO[R, E]) ReaderReaderIOEither[R, C, E, A]
- func MonadAlt[R, C, E, A any](first ReaderReaderIOEither[R, C, E, A], ...) ReaderReaderIOEither[R, C, E, A]
- func MonadAp[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], ...) ReaderReaderIOEither[R, C, E, B]
- func MonadApPar[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], ...) ReaderReaderIOEither[R, C, E, B]
- func MonadApSeq[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], ...) ReaderReaderIOEither[R, C, E, B]
- func MonadChain[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f either.Kleisli[E, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainFirst[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainFirstEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f either.Kleisli[E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainFirstIOK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f io.Kleisli[A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainFirstReaderEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f RE.Kleisli[R, E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainFirstReaderIOK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f readerio.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainFirstReaderK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f reader.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadChainIOEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f IOE.Kleisli[E, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainIOK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f io.Kleisli[A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainLeft[R, C, EA, EB, A any](fa ReaderReaderIOEither[R, C, EA, A], f Kleisli[R, C, EB, EA, A]) ReaderReaderIOEither[R, C, EB, A]
- func MonadChainReaderEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f RE.Kleisli[R, E, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainReaderIOK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f readerio.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadChainReaderK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f reader.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, B]
- func MonadFlap[R, C, E, B, A any](fab ReaderReaderIOEither[R, C, E, func(A) B], a A) ReaderReaderIOEither[R, C, E, B]
- func MonadMap[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f func(A) B) ReaderReaderIOEither[R, C, E, B]
- func MonadMapLeft[R, C, E1, E2, A any](fa ReaderReaderIOEither[R, C, E1, A], f func(E1) E2) ReaderReaderIOEither[R, C, E2, A]
- func MonadMapTo[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], b B) ReaderReaderIOEither[R, C, E, B]
- func MonadTap[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadTapEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f either.Kleisli[E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadTapIOK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f io.Kleisli[A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadTapReaderEitherK[R, C, E, A, B any](ma ReaderReaderIOEither[R, C, E, A], f RE.Kleisli[R, E, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadTapReaderIOK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f readerio.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, A]
- func MonadTapReaderK[C, E, R, A, B any](ma ReaderReaderIOEither[R, C, E, A], f reader.Kleisli[R, A, B]) ReaderReaderIOEither[R, C, E, A]
- func Of[R, C, E, A any](a A) ReaderReaderIOEither[R, C, E, A]
- func Retrying[R, C, E, A any](policy retry.RetryPolicy, action Kleisli[R, C, E, retry.RetryStatus, A], ...) ReaderReaderIOEither[R, C, E, A]
- func Right[R, C, E, A any](a A) ReaderReaderIOEither[R, C, E, A]
- func RightIO[R, C, E, A any](ma IO[A]) ReaderReaderIOEither[R, C, E, A]
- func RightReader[C, E, R, A any](ma Reader[R, A]) ReaderReaderIOEither[R, C, E, A]
- func RightReaderIO[C, E, R, A any](ma ReaderIO[R, A]) ReaderReaderIOEither[R, C, E, A]
- type Trampoline
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ChainFirstReaderOptionK ¶
func ChainFirstReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, A]
func ChainLeft ¶
func ChainLeft[R, C, EA, EB, A any](f Kleisli[R, C, EB, EA, A]) func(ReaderReaderIOEither[R, C, EA, A]) ReaderReaderIOEither[R, C, EB, A]
func ChainOptionK ¶
func ChainReaderOptionK ¶
func ChainReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, B]
func FromOption ¶
func FromPredicate ¶
func Local ¶
func Local[C, E, A, R1, R2 any](f func(R2) R1) func(ReaderReaderIOEither[R1, C, E, A]) ReaderReaderIOEither[R2, C, E, A]
func MapLeft ¶
func MapLeft[R, C, A, E1, E2 any](f func(E1) E2) func(ReaderReaderIOEither[R, C, E1, A]) ReaderReaderIOEither[R, C, E2, A]
func Read ¶
func Read[C, E, A, R any](r R) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
func ReadIO ¶
func ReadIO[C, E, A, R any](rio IO[R]) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
func ReadIOEither ¶
func ReadIOEither[A, R, C, E any](rio IOEither[E, R]) func(ReaderReaderIOEither[R, C, E, A]) ReaderIOEither[C, E, A]
func TapReaderOptionK ¶
func TapReaderOptionK[R, C, A, B, E any](onNone Lazy[E]) func(readeroption.Kleisli[R, A, B]) Operator[R, C, E, A, A]
Types ¶
type Kleisli ¶
type Kleisli[R, C, E, A, B any] = Reader[A, ReaderReaderIOEither[R, C, E, B]]
func FromReaderOption ¶
func FromReaderOption[R, C, A, E any](onNone Lazy[E]) Kleisli[R, C, E, ReaderOption[R, A], A]
type Monoid ¶
func AlternativeMonoid ¶
func ApplicativeMonoid ¶
func ApplicativeMonoidPar ¶
type Operator ¶
type Operator[R, C, E, A, B any] = Kleisli[R, C, E, ReaderReaderIOEither[R, C, E, A], B]
func Alt ¶
func Alt[R, C, E, A any](second Lazy[ReaderReaderIOEither[R, C, E, A]]) Operator[R, C, E, A, A]
func Ap ¶
func Ap[B, R, C, E, A any](fa ReaderReaderIOEither[R, C, E, A]) Operator[R, C, E, func(A) B, B]
func ApEitherS ¶
func ApEitherS[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, fa Either[E, T], ) Operator[R, C, E, S1, S2]
ApEitherS applies an Either computation and attaches its result to the context.
func ApEitherSL ¶
func ApEitherSL[R, C, E, S, T any]( lens Lens[S, T], fa Either[E, T], ) Operator[R, C, E, S, S]
ApEitherSL is a lens-based version of ApEitherS.
func ApIOEitherS ¶
func ApIOEitherS[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, fa IOEither[E, T], ) Operator[R, C, E, S1, S2]
ApIOEitherS applies an IOEither computation and attaches its result to the context.
func ApIOEitherSL ¶
func ApIOEitherSL[R, C, E, S, T any]( lens Lens[S, T], fa IOEither[E, T], ) Operator[R, C, E, S, S]
ApIOEitherSL is a lens-based version of ApIOEitherS.
func ApIOS ¶
func ApIOS[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, fa IO[T], ) Operator[R, C, E, S1, S2]
ApIOS applies an IO computation and attaches its result to the context.
func ApIOSL ¶
func ApIOSL[R, C, E, S, T any]( lens Lens[S, T], fa IO[T], ) Operator[R, C, E, S, S]
ApIOSL is a lens-based version of ApIOS.
func ApReaderIOS ¶
func ApReaderIOS[C, E, R, S1, S2, T any]( setter func(T) func(S1) S2, fa ReaderIO[R, T], ) Operator[R, C, E, S1, S2]
ApReaderIOS applies a ReaderIO computation and attaches its result to the context.
func ApReaderIOSL ¶
func ApReaderIOSL[C, E, R, S, T any]( lens Lens[S, T], fa ReaderIO[R, T], ) Operator[R, C, E, S, S]
ApReaderIOSL is a lens-based version of ApReaderIOS.
func ApReaderS ¶
func ApReaderS[C, E, R, S1, S2, T any]( setter func(T) func(S1) S2, fa Reader[R, T], ) Operator[R, C, E, S1, S2]
ApReaderS applies a Reader computation and attaches its result to the context.
func ApReaderSL ¶
func ApReaderSL[C, E, R, S, T any]( lens Lens[S, T], fa Reader[R, T], ) Operator[R, C, E, S, S]
ApReaderSL is a lens-based version of ApReaderS.
func ApS ¶
func ApS[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, fa ReaderReaderIOEither[R, C, E, T], ) Operator[R, C, E, S1, S2]
ApS applies a computation in parallel (applicative style) and attaches its result to the context. Unlike Bind, this doesn't allow the computation to depend on the current context state.
Example:
readerreaderioeither.ApS(
func(count int) func(State) State {
return func(s State) State { s.Count = count; return s }
},
getCount, // ReaderReaderIOEither[OuterEnv, InnerEnv, error, int]
)
func ApSL ¶
func ApSL[R, C, E, S, T any]( lens Lens[S, T], fa ReaderReaderIOEither[R, C, E, T], ) Operator[R, C, E, S, S]
ApSL is a lens-based version of ApS that uses a lens to focus on a specific field in the context.
func Bind ¶
func Bind[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, f func(S1) ReaderReaderIOEither[R, C, E, T], ) Operator[R, C, E, S1, S2]
Bind attaches the result of a computation to a context [S1] to produce a context [S2]. This enables sequential composition where each step can depend on the results of previous steps and access both the outer (R) and inner (C) reader environments.
The setter function takes the result of the computation and returns a function that updates the context from S1 to S2.
Example:
type State struct {
User User
Posts []Post
}
type OuterEnv struct {
Database string
}
type InnerEnv struct {
UserRepo UserRepository
PostRepo PostRepository
}
result := F.Pipe2(
readerreaderioeither.Do[OuterEnv, InnerEnv, error](State{}),
readerreaderioeither.Bind(
func(user User) func(State) State {
return func(s State) State { s.User = user; return s }
},
func(s State) readerreaderioeither.ReaderReaderIOEither[OuterEnv, InnerEnv, error, User] {
return func(outer OuterEnv) readerioeither.ReaderIOEither[InnerEnv, error, User] {
return readerioeither.Asks(func(inner InnerEnv) ioeither.IOEither[error, User] {
return inner.UserRepo.FindUser(outer.Database)
})
}
},
),
readerreaderioeither.Bind(
func(posts []Post) func(State) State {
return func(s State) State { s.Posts = posts; return s }
},
func(s State) readerreaderioeither.ReaderReaderIOEither[OuterEnv, InnerEnv, error, []Post] {
return func(outer OuterEnv) readerioeither.ReaderIOEither[InnerEnv, error, []Post] {
return readerioeither.Asks(func(inner InnerEnv) ioeither.IOEither[error, []Post] {
return inner.PostRepo.FindPostsByUser(outer.Database, s.User.ID)
})
}
},
),
)
func BindEitherK ¶
func BindEitherK[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, f either.Kleisli[E, S1, T], ) Operator[R, C, E, S1, S2]
BindEitherK binds a computation that returns an Either to the context. The Kleisli function is automatically lifted into ReaderReaderIOEither.
func BindIOEitherK ¶
func BindIOEitherK[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, f ioeither.Kleisli[E, S1, T], ) Operator[R, C, E, S1, S2]
BindIOEitherK binds a computation that returns an IOEither to the context. The Kleisli function is automatically lifted into ReaderReaderIOEither.
func BindIOEitherKL ¶
func BindIOEitherKL[R, C, E, S, T any]( lens Lens[S, T], f ioeither.Kleisli[E, T, T], ) Operator[R, C, E, S, S]
BindIOEitherKL is a lens-based version of BindIOEitherK.
func BindIOK ¶
func BindIOK[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, f io.Kleisli[S1, T], ) Operator[R, C, E, S1, S2]
BindIOK binds a computation that returns an IO to the context. The Kleisli function is automatically lifted into ReaderReaderIOEither.
func BindL ¶
func BindL[R, C, E, S, T any]( lens Lens[S, T], f func(T) ReaderReaderIOEither[R, C, E, T], ) Operator[R, C, E, S, S]
BindL is a lens-based version of Bind that uses a lens to focus on a specific field in the context.
func BindReaderIOK ¶
func BindReaderIOK[C, E, R, S1, S2, T any]( setter func(T) func(S1) S2, f readerio.Kleisli[R, S1, T], ) Operator[R, C, E, S1, S2]
BindReaderIOK binds a computation that returns a ReaderIO to the context. The Kleisli function is automatically lifted into ReaderReaderIOEither.
func BindReaderIOKL ¶
func BindReaderIOKL[C, E, R, S, T any]( lens Lens[S, T], f readerio.Kleisli[R, T, T], ) Operator[R, C, E, S, S]
BindReaderIOKL is a lens-based version of BindReaderIOK.
func BindReaderK ¶
func BindReaderK[C, E, R, S1, S2, T any]( setter func(T) func(S1) S2, f reader.Kleisli[R, S1, T], ) Operator[R, C, E, S1, S2]
BindReaderK binds a computation that returns a Reader to the context. The Kleisli function is automatically lifted into ReaderReaderIOEither.
func BindReaderKL ¶
func BindReaderKL[C, E, R, S, T any]( lens Lens[S, T], f reader.Kleisli[R, T, T], ) Operator[R, C, E, S, S]
BindReaderKL is a lens-based version of BindReaderK.
func BindTo ¶
func BindTo[R, C, E, S1, T any]( setter func(T) S1, ) Operator[R, C, E, T, S1]
BindTo wraps a value of type T into a context S1 using the provided setter function. This is typically used as the first operation after Do to initialize the context.
Example:
F.Pipe1(
readerreaderioeither.Of[OuterEnv, InnerEnv, error](42),
readerreaderioeither.BindTo(func(n int) State { return State{Count: n} }),
)
func ChainEitherK ¶
func ChainFirst ¶
func ChainFirst[R, C, E, A, B any](f Kleisli[R, C, E, A, B]) Operator[R, C, E, A, A]
func ChainFirstEitherK ¶
func ChainFirstIOK ¶
func ChainFirstReaderEitherK ¶
func ChainFirstReaderIOK ¶
func ChainFirstReaderK ¶
func ChainIOEitherK ¶
func ChainReaderEitherK ¶
func ChainReaderIOK ¶
func ChainReaderK ¶
func Let ¶
func Let[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, f func(S1) T, ) Operator[R, C, E, S1, S2]
Let attaches a pure computation result to a context [S1] to produce a context [S2]. Unlike Bind, the computation function f is pure (doesn't perform effects).
Example:
readerreaderioeither.Let(
func(fullName string) func(State) State {
return func(s State) State { s.FullName = fullName; return s }
},
func(s State) string {
return s.FirstName + " " + s.LastName
},
)
func LetL ¶
func LetL[R, C, E, S, T any]( lens Lens[S, T], f func(T) T, ) Operator[R, C, E, S, S]
LetL is a lens-based version of Let that uses a lens to focus on a specific field in the context.
func LetTo ¶
func LetTo[R, C, E, S1, S2, T any]( setter func(T) func(S1) S2, b T, ) Operator[R, C, E, S1, S2]
LetTo attaches a constant value to a context [S1] to produce a context [S2].
Example:
readerreaderioeither.LetTo(
func(status string) func(State) State {
return func(s State) State { s.Status = status; return s }
},
"active",
)
func LetToL ¶
func LetToL[R, C, E, S, T any]( lens Lens[S, T], b T, ) Operator[R, C, E, S, S]
LetToL is a lens-based version of LetTo that uses a lens to focus on a specific field in the context.
func TapEitherK ¶
func TapReaderEitherK ¶
func TapReaderIOK ¶
func TapReaderK ¶
type ReaderIOEither ¶
type ReaderIOEither[R, E, A any] = readerioeither.ReaderIOEither[R, E, A]
type ReaderOption ¶
type ReaderOption[R, A any] = readeroption.ReaderOption[R, A]
type ReaderReaderIOEither ¶
type ReaderReaderIOEither[R, C, E, A any] = Reader[R, ReaderIOEither[C, E, A]]
func Bracket ¶
func Bracket[ R, C, E, A, B, ANY any]( acquire ReaderReaderIOEither[R, C, E, A], use func(A) ReaderReaderIOEither[R, C, E, B], release func(A, Either[E, B]) ReaderReaderIOEither[R, C, E, ANY], ) ReaderReaderIOEither[R, C, E, B]
Bracket ensures that a resource is properly cleaned up regardless of whether the operation succeeds or fails. It follows the acquire-use-release pattern with access to both outer (R) and inner (C) reader contexts.
The release action is always called after the use action completes, whether it succeeds or fails. This makes it ideal for managing resources like file handles, database connections, or locks.
Parameters:
- acquire: Acquires the resource, returning a ReaderReaderIOEither[R, C, E, A]
- use: Uses the acquired resource to perform an operation, returning ReaderReaderIOEither[R, C, E, B]
- release: Releases the resource, receiving both the resource and the result of use
Returns:
- A ReaderReaderIOEither[R, C, E, B] that safely manages the resource lifecycle
The release function receives:
- The acquired resource (A)
- The result of the use function (Either[E, B])
Example:
type OuterConfig struct {
ConnectionPool string
}
type InnerConfig struct {
Timeout time.Duration
}
// Acquire a database connection
acquire := func(outer OuterConfig) readerioeither.ReaderIOEither[InnerConfig, error, *sql.DB] {
return func(inner InnerConfig) ioeither.IOEither[error, *sql.DB] {
return ioeither.TryCatch(
func() (*sql.DB, error) {
return sql.Open("postgres", outer.ConnectionPool)
},
func(err error) error { return err },
)
}
}
// Use the connection
use := func(db *sql.DB) readerreaderioeither.ReaderReaderIOEither[OuterConfig, InnerConfig, error, []User] {
return func(outer OuterConfig) readerioeither.ReaderIOEither[InnerConfig, error, []User] {
return func(inner InnerConfig) ioeither.IOEither[error, []User] {
return queryUsers(db, inner.Timeout)
}
}
}
// Release the connection
release := func(db *sql.DB, result either.Either[error, []User]) readerreaderioeither.ReaderReaderIOEither[OuterConfig, InnerConfig, error, any] {
return func(outer OuterConfig) readerioeither.ReaderIOEither[InnerConfig, error, any] {
return func(inner InnerConfig) ioeither.IOEither[error, any] {
return ioeither.TryCatch(
func() (any, error) {
return nil, db.Close()
},
func(err error) error { return err },
)
}
}
}
result := readerreaderioeither.Bracket(acquire, use, release)
func Do ¶
func Do[R, C, E, S any]( empty S, ) ReaderReaderIOEither[R, C, E, S]
Do creates an empty context of type [S] to be used with the Bind operation. This is the starting point for do-notation style composition with two reader contexts.
Example:
type State struct {
User User
Posts []Post
}
type OuterEnv struct {
Database string
}
type InnerEnv struct {
UserRepo UserRepository
PostRepo PostRepository
}
result := readerreaderioeither.Do[OuterEnv, InnerEnv, error](State{})
func Flatten ¶
func Flatten[R, C, E, A any](mma ReaderReaderIOEither[R, C, E, ReaderReaderIOEither[R, C, E, A]]) ReaderReaderIOEither[R, C, E, A]
func FromEither ¶
func FromEither[R, C, E, A any](t Either[E, A]) ReaderReaderIOEither[R, C, E, A]
func FromIOEither ¶
func FromIOEither[R, C, E, A any](ma IOEither[E, A]) ReaderReaderIOEither[R, C, E, A]
func FromReader ¶
func FromReader[C, E, R, A any](ma Reader[R, A]) ReaderReaderIOEither[R, C, E, A]
func FromReaderEither ¶
func FromReaderEither[R, C, E, A any](ma RE.ReaderEither[R, E, A]) ReaderReaderIOEither[R, C, E, A]
func FromReaderIO ¶
func FromReaderIO[C, E, R, A any](ma ReaderIO[R, A]) ReaderReaderIOEither[R, C, E, A]
func FromReaderIOEither ¶
func FromReaderIOEither[C, E, R, A any](ma ReaderIOEither[R, E, A]) ReaderReaderIOEither[R, C, E, A]
func LeftReader ¶
func LeftReader[C, A, R, E any](ma Reader[R, E]) ReaderReaderIOEither[R, C, E, A]
func LeftReaderIO ¶
func LeftReaderIO[C, A, R, E any](me ReaderIO[R, E]) ReaderReaderIOEither[R, C, E, A]
func MonadAlt ¶
func MonadAlt[R, C, E, A any](first ReaderReaderIOEither[R, C, E, A], second Lazy[ReaderReaderIOEither[R, C, E, A]]) ReaderReaderIOEither[R, C, E, A]
func MonadAp ¶
func MonadAp[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], fa ReaderReaderIOEither[R, C, E, A]) ReaderReaderIOEither[R, C, E, B]
func MonadApPar ¶
func MonadApPar[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], fa ReaderReaderIOEither[R, C, E, A]) ReaderReaderIOEither[R, C, E, B]
func MonadApSeq ¶
func MonadApSeq[R, C, E, A, B any](fab ReaderReaderIOEither[R, C, E, func(A) B], fa ReaderReaderIOEither[R, C, E, A]) ReaderReaderIOEither[R, C, E, B]
func MonadChain ¶
func MonadChain[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, B]
func MonadChainEitherK ¶
func MonadChainFirst ¶
func MonadChainFirst[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, A]
func MonadChainFirstEitherK ¶
func MonadChainFirstIOK ¶
func MonadChainFirstReaderK ¶
func MonadChainIOEitherK ¶
func MonadChainIOK ¶
func MonadChainLeft ¶
func MonadChainLeft[R, C, EA, EB, A any](fa ReaderReaderIOEither[R, C, EA, A], f Kleisli[R, C, EB, EA, A]) ReaderReaderIOEither[R, C, EB, A]
func MonadChainReaderEitherK ¶
func MonadChainReaderIOK ¶
func MonadChainReaderK ¶
func MonadFlap ¶
func MonadFlap[R, C, E, B, A any](fab ReaderReaderIOEither[R, C, E, func(A) B], a A) ReaderReaderIOEither[R, C, E, B]
func MonadMap ¶
func MonadMap[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f func(A) B) ReaderReaderIOEither[R, C, E, B]
func MonadMapLeft ¶
func MonadMapLeft[R, C, E1, E2, A any](fa ReaderReaderIOEither[R, C, E1, A], f func(E1) E2) ReaderReaderIOEither[R, C, E2, A]
func MonadMapTo ¶
func MonadMapTo[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], b B) ReaderReaderIOEither[R, C, E, B]
func MonadTap ¶
func MonadTap[R, C, E, A, B any](fa ReaderReaderIOEither[R, C, E, A], f Kleisli[R, C, E, A, B]) ReaderReaderIOEither[R, C, E, A]
func MonadTapEitherK ¶
func MonadTapIOK ¶
func MonadTapReaderEitherK ¶
func MonadTapReaderIOK ¶
func MonadTapReaderK ¶
func Retrying ¶
func Retrying[R, C, E, A any]( policy retry.RetryPolicy, action Kleisli[R, C, E, retry.RetryStatus, A], check Predicate[Either[E, A]], ) ReaderReaderIOEither[R, C, E, A]
Retrying retries an action according to a retry policy until it succeeds or the policy gives up. The action receives a RetryStatus that tracks the retry attempt number and cumulative delay. The check predicate determines whether a result should trigger a retry.
This is useful for operations that may fail transiently and need to be retried with backoff, while having access to both outer (R) and inner (C) reader contexts.
Parameters:
- policy: The retry policy that determines delays and when to give up
- action: A Kleisli function that takes RetryStatus and returns a ReaderReaderIOEither
- check: A predicate that returns true if the result should trigger a retry
Returns:
- A ReaderReaderIOEither that will retry according to the policy
Example:
type OuterConfig struct {
MaxRetries int
}
type InnerConfig struct {
Endpoint string
}
// Retry a network call with exponential backoff
policy := retry.ExponentialBackoff(100*time.Millisecond, 2.0)
action := func(status retry.RetryStatus) readerreaderioeither.ReaderReaderIOEither[OuterConfig, InnerConfig, error, Response] {
return func(outer OuterConfig) readerioeither.ReaderIOEither[InnerConfig, error, Response] {
return func(inner InnerConfig) ioeither.IOEither[error, Response] {
return ioeither.TryCatch(
func() (Response, error) {
return makeRequest(inner.Endpoint)
},
func(err error) error { return err },
)
}
}
}
// Retry on network errors
check := func(result either.Either[error, Response]) bool {
return either.IsLeft(result) && isNetworkError(either.GetLeft(result))
}
result := readerreaderioeither.Retrying(policy, action, check)
func RightReader ¶
func RightReader[C, E, R, A any](ma Reader[R, A]) ReaderReaderIOEither[R, C, E, A]
func RightReaderIO ¶
func RightReaderIO[C, E, R, A any](ma ReaderIO[R, A]) ReaderReaderIOEither[R, C, E, A]
type Trampoline ¶
type Trampoline[L, B any] = tailrec.Trampoline[L, B]