More efficient implementations of NonEmptySet and NonEmptyMap, and the plus operators.

Author: ragnese

src/commonMain/kotlin/com/quickbirdstudios/nonEmptyCollection/map/NonEmptyMap+plus.kt

@@ -1,34 +1,29 @@
 package com.quickbirdstudios.nonEmptyCollection.map
 
-operator fun <K, V> NonEmptyMap<K, V>.plus(entry: Pair<K, V>) = copy(rest = rest + entry)
+import kotlin.collections.plus as stdPlus
 
-operator fun <K, V> Map<K, V>.plus(entry: Pair<K, V>) = run {
-    val first = entries.first()
+operator fun <K, V> NonEmptyMap<K, V>.plus(entry: Pair<K, V>): NonEmptyMap<K, V> = full + entry
 
-    NonEmptyMap(
-        first = first.key to first.value,
-        rest = this + mapOf(entry) - first.key
-    )
-}
+operator fun <K, V> Map<K, V>.plus(entry: Pair<K, V>): NonEmptyMap<K, V> = NonEmptyMap(this.stdPlus(entry))
 
-operator fun <K, V> NonEmptyMap<K, V>.plus(other: Map<K, V>) = copy(rest = rest + other)
+operator fun <K, V> NonEmptyMap<K, V>.plus(other: Map<K, V>): NonEmptyMap<K, V> = NonEmptyMap(full.stdPlus(other))
 
 operator fun <K, V> Map<K, V>.plus(
     other: NonEmptyMap<K, V>
-): NonEmptyMap<K, V> = other + this
+): NonEmptyMap<K, V> = NonEmptyMap(this.stdPlus(other.full))
 
 operator fun <K, V> NonEmptyMap<K, V>.plus(
     other: NonEmptyMap<K, V>
-): NonEmptyMap<K, V> = this as Map<K, V> + other
+): NonEmptyMap<K, V> = full + other
 
 operator fun <K, V> NonEmptyMap<K, V>.plus(
     other: Iterable<Pair<K, V>>
-): NonEmptyMap<K, V> = this + other.toMap()
+): NonEmptyMap<K, V> = NonEmptyMap(full.stdPlus(other))
 
 operator fun <K, V> NonEmptyMap<K, V>.plus(
     other: Sequence<Pair<K, V>>
-): NonEmptyMap<K, V> = this + other.toMap()
+): NonEmptyMap<K, V> = NonEmptyMap(full.stdPlus(other))
 
 operator fun <K, V> NonEmptyMap<K, V>.plus(
     other: Array<Pair<K, V>>
-): NonEmptyMap<K, V> = this + other.toMap()
+): NonEmptyMap<K, V> = NonEmptyMap(full.stdPlus(other))

src/commonMain/kotlin/com/quickbirdstudios/nonEmptyCollection/map/NonEmptyMap.kt

@@ -1,34 +1,18 @@
 package com.quickbirdstudios.nonEmptyCollection.map
 
-import com.quickbirdstudios.nonEmptyCollection.NonEmptyCollection
-import com.quickbirdstudios.nonEmptyCollection.set.NonEmptySet
-import com.quickbirdstudios.nonEmptyCollection.unsafe.UnsafeNonEmptyCollectionApi
-import com.quickbirdstudios.nonEmptyCollection.unsafe.toNonEmptyList
-import com.quickbirdstudios.nonEmptyCollection.unsafe.toNonEmptySet
-
-data class NonEmptyMap<K, V> internal constructor(
-    internal val first: Pair<K, V>,
-    internal val rest: Map<K, V>
-) : Map<K, V> by mapOf(first) + rest {
-
-    private val map by lazy {
-        mapOf(first) + rest
+class NonEmptyMap<K, out V> internal constructor(internal val full: Map<K, V>) : Map<K, V> by full {
+    constructor(
+        first: Pair<K, V>,
+        rest: Map<K, V>
+    ) : this(LinkedHashMap<K, V>(rest.size + 1).apply { put(first.first, first.second); putAll(rest) })
+
+    init {
+        require(full.isNotEmpty()) { "Fatal Error! This is a bug. Please contact the library author." }
     }
 
-    @OptIn(UnsafeNonEmptyCollectionApi::class)
-    override val entries: NonEmptySet<Map.Entry<K, V>>
-        get() = map.entries.toNonEmptySet()
-
-    @OptIn(UnsafeNonEmptyCollectionApi::class)
-    override val keys: NonEmptySet<K>
-        get() = map.keys.toNonEmptySet()
-
-    @OptIn(UnsafeNonEmptyCollectionApi::class)
-    override val values: NonEmptyCollection<V>
-        get() = map.values.toNonEmptyList()
-
-    override fun equals(other: Any?): Boolean = toMap() == other
+    override fun toString(): String = full.toString()
 
-    override fun hashCode(): Int = toMap().hashCode()
+    override fun equals(other: Any?): Boolean = full == other
 
+    override fun hashCode(): Int = full.hashCode()
 }

src/commonMain/kotlin/com/quickbirdstudios/nonEmptyCollection/set/NonEmptySet+plus.kt

@@ -1,34 +1,29 @@
 package com.quickbirdstudios.nonEmptyCollection.set
 
-operator fun <T> NonEmptySet<T>.plus(value: T) = copy(rest = rest + value)
+import kotlin.collections.plus as stdPlus
 
-operator fun <T> Set<T>.plus(value: T) = run {
-    val first = firstOrNull() ?: value
+operator fun <T> NonEmptySet<T>.plus(value: T): NonEmptySet<T> = full + value
 
-    NonEmptySet(
-        first = first,
-        rest = (this.plusElement(value)) - first
-    )
-}
+operator fun <T> Set<T>.plus(value: T): NonEmptySet<T> = NonEmptySet(this.stdPlus(value))
 
-operator fun <T> NonEmptySet<T>.plus(other: Set<T>) = copy(rest = rest union other)
+operator fun <T> NonEmptySet<T>.plus(other: Set<T>) = NonEmptySet(full.stdPlus(other))
 
 operator fun <T> Set<T>.plus(
     other: NonEmptySet<T>
-): NonEmptySet<T> = other + this
+): NonEmptySet<T> = NonEmptySet(this.stdPlus(other.full))
 
 operator fun <T> NonEmptySet<T>.plus(
     other: NonEmptySet<T>
-): NonEmptySet<T> = this as Set<T> + other
+): NonEmptySet<T> = this + other.full
 
 operator fun <T> NonEmptySet<T>.plus(
     other: Iterable<T>
-): NonEmptySet<T> = this + other.toSet()
+): NonEmptySet<T> = NonEmptySet(full.stdPlus(other))
 
 operator fun <T> NonEmptySet<T>.plus(
     other: Sequence<T>
-): NonEmptySet<T> = this + other.toSet()
+): NonEmptySet<T> = NonEmptySet(full.stdPlus(other))
 
 operator fun <T> NonEmptySet<T>.plus(
     other: Array<T>
-): NonEmptySet<T> = this + other.toSet()
+): NonEmptySet<T> = NonEmptySet(full.stdPlus(other))

src/commonMain/kotlin/com/quickbirdstudios/nonEmptyCollection/set/NonEmptySet.kt

@@ -2,12 +2,17 @@ package com.quickbirdstudios.nonEmptyCollection.set
 
 import com.quickbirdstudios.nonEmptyCollection.NonEmptyCollection
 
-data class NonEmptySet<T> internal constructor(
-    internal val first: T,
-    internal val rest: Set<T>
-) : Set<T> by rest.plusElement(first), NonEmptyCollection<T> {
+class NonEmptySet<T> internal constructor(
+    internal val full: Set<T>
+) : Set<T> by full, NonEmptyCollection<T> {
+    constructor(
+        first: T,
+        rest: Set<T>
+    ) : this(HashSet<T>(rest.size + 1).apply { add(first); addAll(rest) })
 
-    override fun equals(other: Any?): Boolean = toSet() == other
+    override fun toString(): String = full.toString()
 
-    override fun hashCode(): Int = toSet().hashCode()
+    override fun equals(other: Any?): Boolean = full == other
+
+    override fun hashCode(): Int = full.hashCode()
 }