September 2017 Update

Task/Doubly-linked-list-Element-definition/Bracmat/doubly-linked-list-element-definition.bracmat

@@ -0,0 +1 @@
+link=(prev=) (next=) (data=)

Task/Doubly-linked-list-Element-definition/Kotlin/doubly-linked-list-element-definition.kotlin

@@ -0,0 +1,24 @@
+// version 1.1.2
+
+class Node<T: Number>(var data: T, var prev: Node<T>? = null, var next: Node<T>? = null) {
+    override fun toString(): String {
+        val sb = StringBuilder(this.data.toString())
+        var node = this.next
+        while (node != null) {
+            sb.append(" -> ", node.data.toString())
+            node = node.next
+        }
+        return sb.toString()
+    }
+}
+
+fun main(args: Array<String>) {
+    val n1 = Node(1)
+    val n2 = Node(2, n1)
+    n1.next = n2
+    val n3 = Node(3, n2)
+    n2.next = n3
+    println(n1)
+    println(n2)
+    println(n3)
+}

Task/Doubly-linked-list-Element-definition/Oberon-2/doubly-linked-list-element-definition.oberon-2

@@ -0,0 +1,19 @@
+MODULE Box;
+TYPE
+        Object* = POINTER TO ObjectDesc;
+	ObjectDesc* = (* ABSTRACT *) RECORD
+	END;
+
+        (* ... *)
+END Box.
+
+MODULE Collections;
+TYPE
+	Node* = POINTER TO NodeDesc;
+	NodeDesc* = (* ABSTRACT *) RECORD
+		prev-,next-: Node;
+                value-: Box.Object;
+	END;
+
+        (* ... *)
+END Collections.

Task/Doubly-linked-list-Element-definition/Phix/doubly-linked-list-element-definition.phix

@@ -0,0 +1,4 @@
+enum NEXT,PREV,DATA
+type slnode(object x)
+    return (sequence(x) and length(x)=DATA and <i>udt</i>(x[DATA]) and integer(x[NEXT] and integer(x[PREV]))
+end type

Task/Doubly-linked-list-Element-definition/Rust/doubly-linked-list-element-definition-2.rust

@@ -1,17 +1,12 @@
-pub struct LinkedList<T> { // User-facing implementation
-    length: usize,
-    list_head: Link<T>,
-    list_tail: Rawlink<Node<T>>,
-}
-
-type Link<T> = Option<Box<Node<T>>>; // Type definition
-
-struct Rawlink<T> { // Pointer is wrapped in struct so that Option-like methods can be added to it later (wrappers around NULL checks)
-    p: *mut T, // Raw mutable pointer
+pub struct LinkedList<T> {
+    head: Option<Shared<Node<T>>>,
+    tail: Option<Shared<Node<T>>>,
+    len: usize,
+    marker: PhantomData<Box<Node<T>>>, // Indicates that we logically own a boxed (owned pointer) Node<T>>
 }
 
 struct Node<T> {
-    next: Link<T>,
-    prev: Rawlink<Node<T>>,
-    value: T,
+    next: Option<Shared<Node<T>>>,
+    prev: Option<Shared<Node<T>>>,
+    element: T,
 }

Task/Doubly-linked-list-Element-definition/Zkl/doubly-linked-list-element-definition-1.zkl

@@ -0,0 +1,5 @@
+class Node{
+   fcn init(_value,_prev=Void,_next=Void)
+      { var value=_value, prev=_prev, next=_next; }
+   fcn toString{ value.toString() }
+}

Task/Doubly-linked-list-Element-definition/Zkl/doubly-linked-list-element-definition-2.zkl

@@ -0,0 +1,3 @@
+a,b:=Node(1),Node("three");
+a.next=b; b.prev=a;
+println(a.next,"  ",b.prev);