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Author SHA1 Message Date
Dr. Carsten Leue
fd21bdeabf fix: signature of local for context/readerresult
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2026-03-07 22:03:17 +01:00
Dr. Carsten Leue
6834f72856 fix: make signature of Local for context more generic, but backwards compatible
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2026-03-07 21:02:24 +01:00
8 changed files with 110 additions and 70 deletions

View File

@@ -21,6 +21,7 @@ import (
"github.com/IBM/fp-go/v2/function"
"github.com/IBM/fp-go/v2/io"
"github.com/IBM/fp-go/v2/pair"
RIO "github.com/IBM/fp-go/v2/readerio"
)
// Promap is the profunctor map operation that transforms both the input and output of a context-based ReaderIO.
@@ -35,21 +36,24 @@ import (
// The function f returns both a new context and a CancelFunc that should be called to release resources.
//
// Type Parameters:
// - R: The input environment type that f transforms into context.Context
// - A: The original result type produced by the ReaderIO
// - B: The new output result type
//
// Parameters:
// - f: Function to transform the input context (contravariant)
// - f: Function to transform the input environment R into context.Context (contravariant)
// - g: Function to transform the output value from A to B (covariant)
//
// Returns:
// - An Operator that takes a ReaderIO[A] and returns a ReaderIO[B]
// - A Kleisli arrow that takes a ReaderIO[A] and returns a function from R to B
//
// Note: When R is context.Context, this simplifies to an Operator[A, B]
//
//go:inline
func Promap[A, B any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context], g func(A) B) Operator[A, B] {
func Promap[R, A, B any](f pair.Kleisli[context.CancelFunc, R, context.Context], g func(A) B) RIO.Kleisli[R, ReaderIO[A], B] {
return function.Flow2(
Local[A](f),
Map(g),
RIO.Map[R](g),
)
}
@@ -63,15 +67,18 @@ func Promap[A, B any](f pair.Kleisli[context.CancelFunc, context.Context, contex
//
// Type Parameters:
// - A: The result type (unchanged)
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: Function to transform the context, returning a new context and CancelFunc
// - f: Function to transform the input environment R into context.Context, returning a new context and CancelFunc
//
// Returns:
// - An Operator that takes a ReaderIO[A] and returns a ReaderIO[A]
// - A Kleisli arrow that takes a ReaderIO[A] and returns a function from R to A
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
//
//go:inline
func Contramap[A any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context]) Operator[A, A] {
func Contramap[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RIO.Kleisli[R, ReaderIO[A], A] {
return Local[A](f)
}

View File

@@ -634,12 +634,15 @@ func ReadIO[A any](r IO[context.Context]) func(ReaderIO[A]) IO[A] {
//
// Type Parameters:
// - A: The value type of the ReaderIO
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: A function that transforms the context and returns a cancel function
// - f: A function that transforms the input environment R into context.Context and returns a cancel function
//
// Returns:
// - An Operator that runs the computation with the transformed context
// - A Kleisli arrow that runs the computation with the transformed context
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
//
// Example:
//
@@ -649,9 +652,9 @@ func ReadIO[A any](r IO[context.Context]) func(ReaderIO[A]) IO[A] {
// type key int
// const userKey key = 0
//
// addUser := readerio.Local[string](func(ctx context.Context) (context.Context, context.CancelFunc) {
// addUser := readerio.Local[string, context.Context](func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
// newCtx := context.WithValue(ctx, userKey, "Alice")
// return newCtx, func() {} // No-op cancel
// return pair.MakePair(func() {}, newCtx) // No-op cancel
// })
//
// getUser := readerio.FromReader(func(ctx context.Context) string {
@@ -670,19 +673,20 @@ func ReadIO[A any](r IO[context.Context]) func(ReaderIO[A]) IO[A] {
// Timeout Example:
//
// // Add a 5-second timeout to a specific operation
// withTimeout := readerio.Local[Data](func(ctx context.Context) (context.Context, context.CancelFunc) {
// return context.WithTimeout(ctx, 5*time.Second)
// withTimeout := readerio.Local[Data, context.Context](func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
// newCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
// return pair.MakePair(cancel, newCtx)
// })
//
// result := F.Pipe1(
// fetchData,
// withTimeout,
// )
func Local[A any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context]) Operator[A, A] {
return func(rr ReaderIO[A]) ReaderIO[A] {
return func(ctx context.Context) IO[A] {
func Local[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RIO.Kleisli[R, ReaderIO[A], A] {
return func(rr ReaderIO[A]) RIO.ReaderIO[R, A] {
return func(r R) IO[A] {
return func() A {
otherCancel, otherCtx := pair.Unpack(f(ctx))
otherCancel, otherCtx := pair.Unpack(f(r))
defer otherCancel()
return rr(otherCtx)()
}

View File

@@ -22,6 +22,7 @@ import (
"github.com/IBM/fp-go/v2/io"
"github.com/IBM/fp-go/v2/ioresult"
"github.com/IBM/fp-go/v2/pair"
RIOR "github.com/IBM/fp-go/v2/readerioresult"
"github.com/IBM/fp-go/v2/result"
)
@@ -38,21 +39,24 @@ import (
// The error type is fixed as error and remains unchanged through the transformation.
//
// Type Parameters:
// - R: The input environment type that f transforms into context.Context
// - A: The original success type produced by the ReaderIOResult
// - B: The new output success type
//
// Parameters:
// - f: Function to transform the input context (contravariant)
// - f: Function to transform the input environment R into context.Context (contravariant)
// - g: Function to transform the output success value from A to B (covariant)
//
// Returns:
// - An Operator that takes a ReaderIOResult[A] and returns a ReaderIOResult[B]
// - A Kleisli arrow that takes a ReaderIOResult[A] and returns a function from R to B
//
// Note: When R is context.Context, this simplifies to an Operator[A, B]
//
//go:inline
func Promap[A, B any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context], g func(A) B) Operator[A, B] {
func Promap[R, A, B any](f pair.Kleisli[context.CancelFunc, R, context.Context], g func(A) B) RIOR.Kleisli[R, ReaderIOResult[A], B] {
return function.Flow2(
Local[A](f),
Map(g),
RIOR.Map[R](g),
)
}
@@ -66,15 +70,18 @@ func Promap[A, B any](f pair.Kleisli[context.CancelFunc, context.Context, contex
//
// Type Parameters:
// - A: The success type (unchanged)
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: Function to transform the context, returning a new context and CancelFunc
// - f: Function to transform the input environment R into context.Context, returning a new context and CancelFunc
//
// Returns:
// - An Operator that takes a ReaderIOResult[A] and returns a ReaderIOResult[A]
// - A Kleisli arrow that takes a ReaderIOResult[A] and returns a function from R to A
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
//
//go:inline
func Contramap[A any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context]) Operator[A, A] {
func Contramap[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RIOR.Kleisli[R, ReaderIOResult[A], A] {
return Local[A](f)
}

View File

@@ -32,7 +32,6 @@ import (
"github.com/IBM/fp-go/v2/reader"
RIOR "github.com/IBM/fp-go/v2/readerioresult"
"github.com/IBM/fp-go/v2/readeroption"
"github.com/IBM/fp-go/v2/result"
)
const (
@@ -1011,12 +1010,15 @@ func TapLeftIOK[A, B any](f io.Kleisli[error, B]) Operator[A, A] {
//
// Type Parameters:
// - A: The value type of the ReaderIOResult
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: A function that transforms the context and returns a cancel function
// - f: A function that transforms the input environment R into context.Context and returns a cancel function
//
// Returns:
// - An Operator that runs the computation with the transformed context
// - A Kleisli arrow that runs the computation with the transformed context
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
//
// Example:
//
@@ -1026,9 +1028,9 @@ func TapLeftIOK[A, B any](f io.Kleisli[error, B]) Operator[A, A] {
// type key int
// const userKey key = 0
//
// addUser := readerioresult.Local[string](func(ctx context.Context) (context.Context, context.CancelFunc) {
// addUser := readerioresult.Local[string, context.Context](func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
// newCtx := context.WithValue(ctx, userKey, "Alice")
// return newCtx, func() {} // No-op cancel
// return pair.MakePair(func() {}, newCtx) // No-op cancel
// })
//
// getUser := readerioresult.FromReader(func(ctx context.Context) string {
@@ -1047,27 +1049,19 @@ func TapLeftIOK[A, B any](f io.Kleisli[error, B]) Operator[A, A] {
// Timeout Example:
//
// // Add a 5-second timeout to a specific operation
// withTimeout := readerioresult.Local[Data](func(ctx context.Context) (context.Context, context.CancelFunc) {
// return context.WithTimeout(ctx, 5*time.Second)
// withTimeout := readerioresult.Local[Data, context.Context](func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
// newCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
// return pair.MakePair(cancel, newCtx)
// })
//
// result := F.Pipe1(
// fetchData,
// withTimeout,
// )
func Local[A any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context]) Operator[A, A] {
return func(rr ReaderIOResult[A]) ReaderIOResult[A] {
return func(ctx context.Context) IOResult[A] {
return func() Result[A] {
if ctx.Err() != nil {
return result.Left[A](context.Cause(ctx))
}
otherCancel, otherCtx := pair.Unpack(f(ctx))
defer otherCancel()
return rr(otherCtx)()
}
}
}
//
//go:inline
func Local[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RIOR.Kleisli[R, ReaderIOResult[A], A] {
return readerio.Local[Result[A]](f)
}
// WithTimeout adds a timeout to the context for a ReaderIOResult computation.

View File

@@ -13,6 +13,17 @@ import (
// Local modifies the outer environment before passing it to a computation.
// Useful for providing different configurations to sub-computations.
//
// Type Parameters:
// - A: The success type produced by the ReaderReaderIOResult
// - R1: The original outer environment type expected by the ReaderReaderIOResult
// - R2: The new input outer environment type
//
// Parameters:
// - f: A function that transforms R2 to R1
//
// Returns:
// - A function that takes a ReaderReaderIOResult[R1, A] and returns a ReaderReaderIOResult[R2, A]
//
//go:inline
func Local[A, R1, R2 any](f func(R2) R1) func(ReaderReaderIOResult[R1, A]) ReaderReaderIOResult[R2, A] {
return RRIOE.Local[context.Context, error, A](f)

View File

@@ -19,6 +19,8 @@ import (
"context"
"github.com/IBM/fp-go/v2/function"
"github.com/IBM/fp-go/v2/pair"
RR "github.com/IBM/fp-go/v2/readerresult"
)
// Promap is the profunctor map operation that transforms both the input and output of a context-based ReaderResult.
@@ -34,21 +36,24 @@ import (
// The error type is fixed as error and remains unchanged through the transformation.
//
// Type Parameters:
// - R: The input environment type that f transforms into context.Context
// - A: The original success type produced by the ReaderResult
// - B: The new output success type
//
// Parameters:
// - f: Function to transform the input context (contravariant)
// - f: Function to transform the input environment R into context.Context (contravariant)
// - g: Function to transform the output success value from A to B (covariant)
//
// Returns:
// - An Operator that takes a ReaderResult[A] and returns a ReaderResult[B]
// - A Kleisli arrow that takes a ReaderResult[A] and returns a function from R to B
//
// Note: When R is context.Context, this simplifies to an Operator[A, B]
//
//go:inline
func Promap[A, B any](f func(context.Context) (context.Context, context.CancelFunc), g func(A) B) Operator[A, B] {
func Promap[R, A, B any](f pair.Kleisli[context.CancelFunc, R, context.Context], g func(A) B) RR.Kleisli[R, ReaderResult[A], B] {
return function.Flow2(
Local[A](f),
Map(g),
RR.Map[R](g),
)
}
@@ -62,15 +67,18 @@ func Promap[A, B any](f func(context.Context) (context.Context, context.CancelFu
//
// Type Parameters:
// - A: The success type (unchanged)
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: Function to transform the context, returning a new context and CancelFunc
// - f: Function to transform the input environment R into context.Context, returning a new context and CancelFunc
//
// Returns:
// - An Operator that takes a ReaderResult[A] and returns a ReaderResult[A]
// - A Kleisli arrow that takes a ReaderResult[A] and returns a function from R to A
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
//
//go:inline
func Contramap[A any](f func(context.Context) (context.Context, context.CancelFunc)) Operator[A, A] {
func Contramap[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RR.Kleisli[R, ReaderResult[A], A] {
return Local[A](f)
}
@@ -89,16 +97,19 @@ func Contramap[A any](f func(context.Context) (context.Context, context.CancelFu
//
// Type Parameters:
// - A: The result type (unchanged)
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: Function to transform the context, returning a new context and CancelFunc
// - f: Function to transform the input environment R into context.Context, returning a new context and CancelFunc
//
// Returns:
// - An Operator that takes a ReaderResult[A] and returns a ReaderResult[A]
func Local[A any](f func(context.Context) (context.Context, context.CancelFunc)) Operator[A, A] {
return func(rr ReaderResult[A]) ReaderResult[A] {
return func(ctx context.Context) Result[A] {
otherCtx, otherCancel := f(ctx)
// - A Kleisli arrow that takes a ReaderResult[A] and returns a function from R to A
//
// Note: When R is context.Context, this simplifies to an Operator[A, A]
func Local[A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) RR.Kleisli[R, ReaderResult[A], A] {
return func(rr ReaderResult[A]) RR.ReaderResult[R, A] {
return func(r R) Result[A] {
otherCancel, otherCtx := pair.Unpack(f(r))
defer otherCancel()
return rr(otherCtx)
}

View File

@@ -20,6 +20,7 @@ import (
"strconv"
"testing"
"github.com/IBM/fp-go/v2/pair"
R "github.com/IBM/fp-go/v2/result"
"github.com/stretchr/testify/assert"
)
@@ -34,9 +35,9 @@ func TestPromapBasic(t *testing.T) {
return R.Of(0)
}
addKey := func(ctx context.Context) (context.Context, context.CancelFunc) {
addKey := func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
newCtx := context.WithValue(ctx, "key", 42)
return newCtx, func() {}
return pair.MakePair[context.CancelFunc](func() {}, newCtx)
}
toString := strconv.Itoa
@@ -57,9 +58,9 @@ func TestContramapBasic(t *testing.T) {
return R.Of(0)
}
addKey := func(ctx context.Context) (context.Context, context.CancelFunc) {
addKey := func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
newCtx := context.WithValue(ctx, "key", 100)
return newCtx, func() {}
return pair.MakePair[context.CancelFunc](func() {}, newCtx)
}
adapted := Contramap[int](addKey)(getValue)
@@ -79,9 +80,9 @@ func TestLocalBasic(t *testing.T) {
return R.Of("unknown")
}
addUser := func(ctx context.Context) (context.Context, context.CancelFunc) {
addUser := func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
newCtx := context.WithValue(ctx, "user", "Alice")
return newCtx, func() {}
return pair.MakePair[context.CancelFunc](func() {}, newCtx)
}
adapted := Local[string](addUser)(getValue)

View File

@@ -23,6 +23,7 @@ import (
"github.com/IBM/fp-go/v2/internal/statet"
"github.com/IBM/fp-go/v2/pair"
"github.com/IBM/fp-go/v2/result"
SRIOE "github.com/IBM/fp-go/v2/statereaderioeither"
)
// Left creates a StateReaderIOResult that represents a failed computation with the given error.
@@ -215,24 +216,28 @@ func FromResult[S, A any](ma Result[A]) StateReaderIOResult[S, A] {
// Type Parameters:
// - S: The state type
// - A: The result type
// - R: The input environment type that f transforms into context.Context
//
// Parameters:
// - f: Function to transform the context, returning a new context and CancelFunc
// - f: Function to transform the input environment R into context.Context, returning a new context and CancelFunc
//
// Returns:
// - A function that takes a StateReaderIOResult[S, A] and returns a StateReaderIOResult[S, A]
// - A Kleisli arrow that takes a StateReaderIOResult[S, A] and returns a StateReaderIOEither[S, R, error, A]
//
// Note: When R is context.Context, the return type simplifies to func(StateReaderIOResult[S, A]) StateReaderIOResult[S, A]
//
// Example:
//
// // Add a timeout to a specific operation
// withTimeout := statereaderioresult.Local[AppState, Data](
// func(ctx context.Context) (context.Context, context.CancelFunc) {
// return context.WithTimeout(ctx, 60*time.Second)
// withTimeout := statereaderioresult.Local[AppState, Data, context.Context](
// func(ctx context.Context) pair.Pair[context.CancelFunc, context.Context] {
// newCtx, cancel := context.WithTimeout(ctx, 60*time.Second)
// return pair.MakePair(cancel, newCtx)
// },
// )
// result := withTimeout(computation)
func Local[S, A any](f pair.Kleisli[context.CancelFunc, context.Context, context.Context]) Operator[S, A, A] {
return func(ma StateReaderIOResult[S, A]) StateReaderIOResult[S, A] {
func Local[S, A, R any](f pair.Kleisli[context.CancelFunc, R, context.Context]) SRIOE.Kleisli[S, R, error, StateReaderIOResult[S, A], A] {
return func(ma StateReaderIOResult[S, A]) SRIOE.StateReaderIOEither[S, R, error, A] {
return function.Flow2(ma, RIORES.Local[Pair[S, A]](f))
}
}