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99 lines
3.9 KiB
Go
99 lines
3.9 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 readeroption
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import (
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G "github.com/IBM/fp-go/v2/readeroption/generic"
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)
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// From functions convert Go functions that take a context as the first parameter
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// and return (value, bool) into ReaderOption functions with uncurried parameters.
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//
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// Unlike Curry functions which return fully curried functions, From functions
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// return functions that take multiple parameters at once (uncurried style).
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//
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// This follows the Go convention of passing context as the first parameter
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// (see https://pkg.go.dev/context), while providing a functional programming interface.
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//
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// The bool return value indicates success (true) or failure (false), which maps to
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// Some or None in the Option monad.
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// From0 converts a function that takes only a context and returns (A, bool)
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// into a function that returns a ReaderOption[R, A].
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//
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// Example:
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//
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// getConfig := func(ctx context.Context) (Config, bool) {
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// cfg, ok := ctx.Value("config").(Config)
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// return cfg, ok
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// }
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// roFunc := readeroption.From0(getConfig)
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// ro := roFunc() // Returns a ReaderOption[context.Context, Config]
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// result := ro(ctx) // Returns option.Some(config) or option.None()
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func From0[R, A any](f func(R) (A, bool)) func() ReaderOption[R, A] {
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return G.From0[ReaderOption[R, A]](f)
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}
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// From1 converts a function that takes a context and one argument, returning (A, bool),
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// into a function that takes one argument and returns a ReaderOption.
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//
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// This is equivalent to Curry1 but provided for consistency with the From naming convention.
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//
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// Example:
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//
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// findUser := func(ctx context.Context, id int) (User, bool) {
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// // Query database using context
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// return user, found
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// }
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// roFunc := readeroption.From1(findUser)
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// ro := roFunc(123) // Returns a ReaderOption[context.Context, User]
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// result := ro(ctx) // Returns option.Some(user) or option.None()
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func From1[R, T1, A any](f func(R, T1) (A, bool)) Kleisli[R, T1, A] {
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return G.From1[ReaderOption[R, A]](f)
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}
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// From2 converts a function that takes a context and two arguments, returning (A, bool),
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// into a function that takes two arguments (uncurried) and returns a ReaderOption.
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//
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// Example:
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//
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// query := func(ctx context.Context, table string, id int) (Record, bool) {
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// // Query database using context
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// return record, found
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// }
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// roFunc := readeroption.From2(query)
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// ro := roFunc("users", 123) // Returns a ReaderOption[context.Context, Record]
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// result := ro(ctx) // Returns option.Some(record) or option.None()
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func From2[R, T1, T2, A any](f func(R, T1, T2) (A, bool)) func(T1, T2) ReaderOption[R, A] {
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return G.From2[ReaderOption[R, A]](f)
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}
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// From3 converts a function that takes a context and three arguments, returning (A, bool),
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// into a function that takes three arguments (uncurried) and returns a ReaderOption.
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//
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// Example:
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//
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// complexQuery := func(ctx context.Context, db string, table string, id int) (Record, bool) {
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// // Query database using context
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// return record, found
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// }
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// roFunc := readeroption.From3(complexQuery)
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// ro := roFunc("mydb", "users", 123) // Returns a ReaderOption[context.Context, Record]
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// result := ro(ctx) // Returns option.Some(record) or option.None()
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func From3[R, T1, T2, T3, A any](f func(R, T1, T2, T3) (A, bool)) func(T1, T2, T3) ReaderOption[R, A] {
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return G.From3[ReaderOption[R, A]](f)
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}
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