Add choose and rename Choice to Choose

Author: kyay10

library/src/jvmMain/kotlin/dsl.kt

@@ -10,48 +10,53 @@ private class PromptFail<R>(private val prompt: Prompt<R>, private val failValue
   override fun raise(e: Unit): Nothing = prompt.abort(failValue)
 }
 
-public typealias Choice = Prompt<Unit>
+public typealias Choose = Prompt<Unit>
 
-public suspend fun <R> Choice.pushChoice(body: suspend () -> R, handler: suspend (R) -> Unit) {
+public suspend fun <R> Choose.pushChoice(body: suspend () -> R, handler: suspend (R) -> Unit) {
   pushPrompt {
     handler(body())
   }
 }
 
 public suspend fun <R> runChoice(
-  body: suspend context(SingletonRaise<Unit>, Choice) () -> R, handler: suspend (R) -> Unit
+  body: suspend context(SingletonRaise<Unit>, Choose) () -> R, handler: suspend (R) -> Unit
 ) {
   val prompt = Prompt<Unit>()
   prompt.pushChoice({
     body(SingletonRaise(PromptFail(prompt, Unit)), prompt)
   }, handler)
 }
 
-public suspend fun <R> Choice.pushList(body: suspend () -> R): List<R> =
+public suspend fun <R> Choose.pushList(body: suspend () -> R): List<R> =
   runForkingReader(mutableListOf(), MutableList<R>::toMutableList) {
     pushChoice(body) {
       ask().add(it)
     }
     ask()
   }
 
-public suspend fun <R> runList(body: suspend context(SingletonRaise<Unit>, Choice) () -> R): List<R> =
+public suspend fun <R> runList(body: suspend context(SingletonRaise<Unit>, Choose) () -> R): List<R> =
   runForkingReader(mutableListOf(), MutableList<R>::toMutableList) {
     runChoice(body) {
       ask().add(it)
     }
     ask()
   }
 
-public suspend fun <R> listReset(body: suspend context(SingletonRaise<Unit>, Choice) () -> R): List<R> =
+public suspend fun <R> listReset(body: suspend context(SingletonRaise<Unit>, Choose) () -> R): List<R> =
   runCC { runList(body) }
 
-context(Choice)
+context(Choose)
 public suspend fun <T> List<T>.bind(): T = shift { continuation ->
   for (item in 0..lastIndex) continuation(this[item])
 }
 
-context(Choice)
+public suspend fun <T> Choose.choose(left: T, right: T): T = shift { continuation ->
+  continuation(left)
+  continuation(right)
+}
+
+context(Choose)
 public suspend fun IntRange.bind(): Int = shift { continuation ->
   for (i in start..endInclusive) continuation(i)
 }
@@ -61,14 +66,14 @@ public suspend fun <T> replicate(amount: Int, producer: suspend (Int) -> T): Lis
 }
 
 public fun <R> flowReset(
-  body: suspend context(SingletonRaise<Unit>, Choice) () -> R
+  body: suspend context(SingletonRaise<Unit>, Choose) () -> R
 ): Flow<R> = channelFlow {
   runCC {
     runChoice(body, this::send)
   }
 }
 
-context(Choice)
+context(Choose)
 @OptIn(ExperimentalCoroutinesApi::class)
 public suspend fun <T> Flow<T>.bind(): T = shift { continuation ->
   // TODO using coroutineScope in such a way is generally unsafe unless a nonReentrant block is used

library/src/jvmTest/kotlin/ListTest.kt

@@ -127,22 +127,20 @@ class ListTest {
 
   @Test
   fun allEightBitPatterns() = runTest {
-    val bits = listOf(0, 1)
     val result = listReset {
       replicate(8) {
-        bits.bind()
+        choose(0, 1)
       }
     }
     result.map { it.joinToString("").toInt(2) } shouldBe (0..255).toList()
   }
 
   @Test
   fun allEightBitPatternsWithOnlyChange() = runTest {
-    val bits = listOf(0, 1)
     val result = buildString {
       listReset {
         repeat(8) {
-          append(bits.bind())
+          append(choose(0, 1))
         }
         appendLine()
       }