Implement v2 using type aliases (#141)

* fix: initial checkin of v2 Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: slowly migrate IO Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate MonadTraverseArray and TraverseArray Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate traversal Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: complete migration of IO Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate ioeither Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: refactorY Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: next step in migration Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: adjust IO generation code Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: get rid of more IO methods Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: get rid of more IO * fix: convert iooption Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: convert reader Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: convert a bit of reader Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: new build script Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: cleanup Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: reformat Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: simplify Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: some cleanup Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: adjust Pair to Haskell semantic Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: documentation and testcases Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: some performance optimizations Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: remove coverage Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: better doc Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> --------- Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2025-11-23 22:14:53 +02:00 · 2025-11-06 09:27:00 +01:00
parent 7874859c4b
commit 3385c705dc
748 changed files with 97722 additions and 24 deletions
--- a/v2/function/generic/cache.go
+++ b/v2/function/generic/cache.go
@@ -0,0 +1,103 @@
+// Copyright (c) 2023 - 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.
+
+package generic
+
+import (
+	"sync"
+
+	L "github.com/IBM/fp-go/v2/internal/lazy"
+)
+
+// Memoize converts a unary function into a unary function that caches the value depending on the parameter
+func Memoize[F ~func(K) T, K comparable, T any](f F) F {
+	return ContramapMemoize[F](func(k K) K { return k })(f)
+}
+
+// ContramapMemoize converts a unary function into a unary function that caches the value depending on the parameter
+func ContramapMemoize[F ~func(A) T, KF func(A) K, A any, K comparable, T any](kf KF) func(F) F {
+	return CacheCallback[func(F) F, func() func() T](kf, getOrCreate[K, T]())
+}
+
+// getOrCreate is a naive implementation of a cache, without bounds
+func getOrCreate[K comparable, T any]() func(K, func() func() T) func() T {
+	cache := make(map[K]func() T)
+	var l sync.Mutex
+
+	return func(k K, cb func() func() T) func() T {
+		// only lock to access a lazy accessor to the value
+		l.Lock()
+		existing, ok := cache[k]
+		if !ok {
+			existing = cb()
+			cache[k] = existing
+		}
+		l.Unlock()
+		// compute the value outside of the lock
+		return existing
+	}
+}
+
+// SingleElementCache is a cache with a capacity of a single element
+func SingleElementCache[
+	LLT ~func() LT, // generator of the generator
+	K comparable, // key into the cache
+	LT ~func() T, // generator of a value
+	T any, // the cached data type
+]() func(K, LLT) LT {
+	var l sync.Mutex
+
+	var key K
+	var value LT
+	hasKey := false
+
+	return func(k K, gen LLT) LT {
+		l.Lock()
+
+		existing := value
+		if !hasKey || key != k {
+			existing = gen()
+			// update state
+			key = k
+			value = existing
+			hasKey = true
+		}
+
+		l.Unlock()
+
+		return existing
+	}
+}
+
+// CacheCallback converts a unary function into a unary function that caches the value depending on the parameter
+func CacheCallback[
+	EM ~func(F) F, // endomorphism of the function
+	LLT ~func() LT, // generator of the generator
+	LT ~func() T, // generator of a value
+	F ~func(A) T, // function to actually cache
+	KF func(A) K, // extracts the cache key from the input
+	C ~func(K, LLT) LT, // the cache callback function
+	A any, K comparable, T any](kf KF, getOrCreate C) EM {
+	return func(f F) F {
+		return func(a A) T {
+			// cache entry
+			return getOrCreate(kf(a), func() LT {
+				return L.Memoize[LT](func() T {
+					return f(a)
+				})
+			})()
+		}
+	}
+}