feat(stdlib): Add toList, fromList, toArray, fromArray to Stack (#2198)

spotandjake · ospencer · web-flow · commit b815bcd17fe0 · 2025-01-02T21:44:05.000Z
Co-authored-by: Oscar Spencer &lt;oscar.spen@gmail.com&gt;
diff --git a/compiler/test/stdlib/stack.test.gr b/compiler/test/stdlib/stack.test.gr
@@ -56,6 +56,44 @@ let stack2 = Stack.make(size=1)
 Stack.push(0, stack2)
 assert stack == stack2
 
+// Stack.toList
+let s = Stack.make()
+assert Stack.toList(s) == []
+Stack.push(1, s)
+Stack.push(2, s)
+Stack.push(3, s)
+assert Stack.toList(s) == [3, 2, 1]
+Stack.pop(s)
+assert Stack.toList(s) == [2, 1]
+
+// Stack.fromList
+let s = Stack.fromList([3, 2, 1])
+assert Stack.pop(s) == Some(3)
+assert Stack.pop(s) == Some(2)
+assert Stack.pop(s) == Some(1)
+assert Stack.pop(s) == None
+let s = Stack.fromList([])
+assert Stack.pop(s) == None
+
+// Stack.toArray
+let s = Stack.make()
+assert Stack.toArray(s) == [>]
+Stack.push(1, s)
+Stack.push(2, s)
+Stack.push(3, s)
+assert Stack.toArray(s) == [> 3, 2, 1]
+Stack.pop(s)
+assert Stack.toArray(s) == [> 2, 1]
+
+// Stack.fromArray
+let s = Stack.fromArray([> 3, 2, 1])
+assert Stack.pop(s) == Some(3)
+assert Stack.pop(s) == Some(2)
+assert Stack.pop(s) == Some(1)
+assert Stack.pop(s) == None
+let s = Stack.fromArray([>])
+assert Stack.pop(s) == None
+
 module Immutable {
   use Stack.{ module Immutable as Stack }
 
@@ -90,4 +128,32 @@ module Immutable {
   assert Stack.size(Stack.empty) == 0
   assert Stack.size(sampleStack) == 3
   assert Stack.size(Stack.pop(Stack.pop(sampleStack))) == 1
+
+  // Stack.toList
+  let stack = Stack.empty
+  let stack = Stack.push(1, stack)
+  let stack = Stack.push(2, stack)
+  assert Stack.toList(stack) == [2, 1]
+
+  // Stack.fromList
+  let stack = Stack.fromList([2, 1])
+  assert Stack.peek(stack) == Some(2)
+  let stack = Stack.pop(stack)
+  assert Stack.peek(stack) == Some(1)
+  let stack = Stack.pop(stack)
+  assert Stack.isEmpty(stack)
+
+  // Stack.toArray
+  let stack = Stack.empty
+  let stack = Stack.push(1, stack)
+  let stack = Stack.push(2, stack)
+  assert Stack.toArray(stack) == [> 2, 1]
+
+  // Stack.fromArray
+  let stack = Stack.fromArray([> 2, 1])
+  assert Stack.peek(stack) == Some(2)
+  let stack = Stack.pop(stack)
+  assert Stack.peek(stack) == Some(1)
+  let stack = Stack.pop(stack)
+  assert Stack.isEmpty(stack)
 }
diff --git a/stdlib/stack.gr b/stdlib/stack.gr
@@ -30,7 +30,7 @@ abstract record Stack<a> {
  *
  * @param size: The initial storage size of the stack
  * @returns An empty stack
- * 
+ *
  * @since v0.6.0
  */
 provide let make = (size=16) => {
@@ -134,6 +134,95 @@ provide let copy = stack => {
   { size, array: Array.copy(array) }
 }
 
+/**
+ * Creates a list containing the elements of a stack.
+ *
+ * @param stack: The stack to convert
+ * @returns A list containing all stack values
+ *
+ * @example
+ * let stack = Stack.make()
+ * Stack.push(1, stack)
+ * Stack.push(2, stack)
+ * assert Stack.toList(stack) == [2, 1]
+ *
+ * @since v0.7.0
+ */
+provide let toList = stack => {
+  let size = stack.size
+  List.init(size, i => match (stack.array[size - i - 1]) {
+    Some(v) => v,
+    None => fail "Impossible: None in stack bounds on toList",
+  })
+}
+
+/**
+ * Creates a stack from a list.
+ *
+ * @param list: The list to convert
+ * @returns A stack containing all list values
+ *
+ * @example
+ * let stack = Stack.fromList([3, 2, 1])
+ * assert Stack.pop(stack) == Some(3)
+ * assert Stack.pop(stack) == Some(2)
+ * assert Stack.pop(stack) == Some(1)
+ * assert Stack.pop(stack) == None
+ *
+ * @since v0.7.0
+ */
+provide let fromList = list => {
+  let stack = make(size=List.length(list))
+  List.forEach(v => push(v, stack), List.reverse(list))
+  stack
+}
+
+/**
+ * Creates an array containing the elements of a stack.
+ *
+ * @param stack: The stack to convert
+ * @returns An array containing all stack values
+ *
+ * @example
+ * let stack = Stack.make()
+ * Stack.push(1, stack)
+ * Stack.push(2, stack)
+ * assert Stack.toArray(stack) == [> 2, 1]
+ *
+ * @since v0.7.0
+ */
+provide let toArray = stack => {
+  let size = stack.size
+  Array.init(size, i => match (stack.array[size - i - 1]) {
+    Some(v) => v,
+    None => fail "Impossible: None in stack bounds on toList",
+  })
+}
+
+/**
+ * Creates a stack from an array.
+ *
+ * @param arr: The array to convert
+ * @returns A stack containing all array values
+ *
+ * @example
+ * let s = Stack.fromArray([> 3, 2, 1])
+ * assert Stack.pop(s) == Some(3)
+ * assert Stack.pop(s) == Some(2)
+ * assert Stack.pop(s) == Some(1)
+ * assert Stack.pop(s) == None
+ *
+ * @since v0.7.0
+ */
+provide let fromArray = arr => {
+  let arrLen = Array.length(arr)
+  let stack = make(size=arrLen)
+  for (let mut i = arrLen - 1; i >= 0; i -= 1) {
+    push(arr[i], stack)
+  }
+  stack
+}
+
 /**
  * An immutable stack implementation.
  */
@@ -237,4 +326,84 @@ provide module Immutable {
       { data } => List.length(data),
     }
   }
+
+  /**
+   * Creates a list containing the elements of a stack.
+   *
+   * @param stack: The stack to convert
+   * @returns A list containing all stack values
+   *
+   * @example
+   * use Stack.{ module Immutable as Stack }
+   * let stack = Stack.empty
+   * let stack = Stack.push(1, stack)
+   * let stack = Stack.push(2, stack)
+   * assert Stack.toList(stack) == [2, 1]
+   *
+   * @since v0.7.0
+   */
+  provide let toList = stack => {
+    stack.data
+  }
+
+  /**
+   * Creates a stack from a list.
+   *
+   * @param list: The list to convert
+   * @returns A stack containing all list values
+   *
+   * @example
+   * use Stack.{ module Immutable as Stack }
+   * let stack = Stack.fromList([2, 1])
+   * assert Stack.peek(stack) == Some(2)
+   * let stack = Stack.pop(stack)
+   * assert Stack.peek(stack) == Some(1)
+   * let stack = Stack.pop(stack)
+   * assert Stack.isEmpty(stack)
+   *
+   * @since v0.7.0
+   */
+  provide let fromList = list => {
+    { data: list, }
+  }
+
+  /**
+   * Creates an array containing the elements of a stack.
+   *
+   * @param stack: The stack to convert
+   * @returns An array containing all stack values
+   *
+   * @example
+   * use Stack.{ module Immutable as Stack }
+   * let stack = Stack.empty
+   * let stack = Stack.push(1, stack)
+   * let stack = Stack.push(2, stack)
+   * assert Stack.toArray(stack) == [> 2, 1]
+   *
+   * @since v0.7.0
+   */
+  provide let toArray = stack => {
+    Array.fromList(stack.data)
+  }
+
+  /**
+   * Creates a stack from an array.
+   *
+   * @param arr: The array to convert
+   * @returns A stack containing all array values
+   *
+   * @example
+   * use Stack.{ module Immutable as Stack }
+   * let stack = Stack.fromArray([> 2, 1])
+   * assert Stack.peek(stack) == Some(2)
+   * let stack = Stack.pop(stack)
+   * assert Stack.peek(stack) == Some(1)
+   * let stack = Stack.pop(stack)
+   * assert Stack.isEmpty(stack)
+   *
+   * @since v0.7.0
+   */
+  provide let fromArray = arr => {
+    { data: Array.toList(arr), }
+  }
 }
diff --git a/stdlib/stack.md b/stdlib/stack.md
