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131 lines
4.2 KiB
Go
131 lines
4.2 KiB
Go
// Copyright (c) 2023 - 2025 IBM Corp.
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// All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package generic
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import (
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"github.com/IBM/fp-go/v2/either"
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A "github.com/IBM/fp-go/v2/internal/apply"
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C "github.com/IBM/fp-go/v2/internal/chain"
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F "github.com/IBM/fp-go/v2/internal/functor"
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)
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// Bind creates an empty context of type [S] to be used with the [Bind] operation
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func Do[GRS ~func(R) GS, GS ~func() either.Either[E, S], R, E, S any](
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empty S,
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) GRS {
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return Of[GRS, GS, R, E, S](empty)
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}
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// Bind attaches the result of a computation to a context [S1] to produce a context [S2]
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func Bind[GRS1 ~func(R) GS1, GRS2 ~func(R) GS2, GRT ~func(R) GT, GS1 ~func() either.Either[E, S1], GS2 ~func() either.Either[E, S2], GT ~func() either.Either[E, T], R, E, S1, S2, T any](
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setter func(T) func(S1) S2,
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f func(S1) GRT,
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) func(GRS1) GRS2 {
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return C.Bind(
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Chain[GRS1, GRS2, GS1, GS2, R, E, S1, S2],
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Map[GRT, GRS2, GT, GS2, R, E, T, S2],
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setter,
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f,
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)
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}
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// Let attaches the result of a computation to a context [S1] to produce a context [S2]
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func Let[GRS1 ~func(R) GS1, GRS2 ~func(R) GS2, GS1 ~func() either.Either[E, S1], GS2 ~func() either.Either[E, S2], R, E, S1, S2, T any](
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key func(T) func(S1) S2,
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f func(S1) T,
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) func(GRS1) GRS2 {
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return F.Let(
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Map[GRS1, GRS2, GS1, GS2, R, E, S1, S2],
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key,
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f,
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)
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}
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// LetTo attaches the a value to a context [S1] to produce a context [S2]
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func LetTo[GRS1 ~func(R) GS1, GRS2 ~func(R) GS2, GS1 ~func() either.Either[E, S1], GS2 ~func() either.Either[E, S2], R, E, S1, S2, B any](
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key func(B) func(S1) S2,
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b B,
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) func(GRS1) GRS2 {
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return F.LetTo(
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Map[GRS1, GRS2, GS1, GS2, R, E, S1, S2],
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key,
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b,
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)
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}
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// BindTo initializes a new state [S1] from a value [T]
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func BindTo[GRS1 ~func(R) GS1, GRT ~func(R) GT, GS1 ~func() either.Either[E, S1], GT ~func() either.Either[E, T], R, E, S1, T any](
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setter func(T) S1,
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) func(GRT) GRS1 {
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return C.BindTo(
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Map[GRT, GRS1, GT, GS1, R, E, T, S1],
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setter,
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)
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}
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// ApS attaches a value to a context [S1] to produce a context [S2] by considering
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// the context and the value concurrently (using Applicative rather than Monad).
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// This allows independent computations to be combined without one depending on the result of the other.
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//
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// Unlike Bind, which sequences operations, ApS can be used when operations are independent
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// and can conceptually run in parallel.
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//
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// Example:
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//
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// type State struct {
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// User User
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// Config Config
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// }
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// type Env struct {
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// UserRepo UserRepository
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// ConfigRepo ConfigRepository
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// }
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//
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// // These operations are independent and can be combined with ApS
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// getUser := func(env Env) ioeither.IOEither[error, User] {
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// return env.UserRepo.FindUser()
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// }
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// getConfig := func(env Env) ioeither.IOEither[error, Config] {
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// return env.ConfigRepo.LoadConfig()
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// }
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//
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// result := F.Pipe2(
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// generic.Do[ReaderIOEither[Env, error, State], IOEither[error, State], Env, error, State](State{}),
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// generic.ApS[...](
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// func(user User) func(State) State {
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// return func(s State) State { s.User = user; return s }
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// },
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// getUser,
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// ),
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// generic.ApS[...](
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// func(cfg Config) func(State) State {
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// return func(s State) State { s.Config = cfg; return s }
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// },
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// getConfig,
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// ),
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// )
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func ApS[GRTS1 ~func(R) GTS1, GRS1 ~func(R) GS1, GRS2 ~func(R) GS2, GRT ~func(R) GT, GTS1 ~func() either.Either[E, func(T) S2], GS1 ~func() either.Either[E, S1], GS2 ~func() either.Either[E, S2], GT ~func() either.Either[E, T], R, E, S1, S2, T any](
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setter func(T) func(S1) S2,
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fa GRT,
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) func(GRS1) GRS2 {
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return A.ApS(
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Ap[GRT, GRS2, GRTS1, GT, GS2, GTS1, R, E, T, S2],
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Map[GRS1, GRTS1, GS1, GTS1, R, E, S1, func(T) S2],
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setter,
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fa,
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)
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}
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