Monkey/Language/Lists

What are Lists? In Monkey, lists are a set of objects that are encapsulated in an object, and read in a set sequential order. Lists have the power to be read forwards, backwards, traversed object-by-object, sorted, and offer a node-level access for insertion and queries. Example: Class Obj Field x:Int, y:Int, z:Int Method New(xx:Int,yy:Int,zz:Int) x=xx; y=yy; z=zz End End Function Main() mylist = New List<Obj> mylist.AddLast(New Obj(1,1,1)) mylist.AddLast(New Obj(2,2,2)) mylist.AddFirst(New Obj(3,3,3)) Print "list:" For Local o:Obj = Eachin mylist Print o.x+" "+o.y+" "+o.z Next End A list is created like any other object with the 'NEW' keyword. It differs from other objects because it requires a type specifier. Type specifiers (or type parameters) are defined using the greater than-less than signs: < and >. In the above example, the list 'mylist' is a list of 'Obj's, which is a class of three fields: x, y, and z. 'EachIn' will automatically iterate through a list, assigning the object to the iterating variable. EachIn will exit the loop when a NULL is reached, signaling the end of the list. What are Nodes? Syntax for a list's node: Local mynode:list.Node<Obj> mynode = mylist.FirstNode() Nodes are also created when an object is added to a list: Local mynode:list.Node<Obj> = mylist.AddLast(New Obj(4,4,4)) Nodes can return a value from the list: Local o:Obj = mynode.Value() Print o.x+" "+o.y+" "+o.z Nodes can be used to iterate through a list backwards: Local mynode:list.Node<Obj> = mylist.LastNode() While mynode Local o:Obj o = mynode.Value() Print o.x+" "+o.y+" "+o.z mynode = mynode.PrevNode() Wend Nodes can insert a value into a list, using the Node constructor (the New command): Local mynode:list.Node<Obj> = mylist.FirstNode() Local insertdata:Obj = New Obj(9,9,9) While mynode If mynode.Value.x = 2 ''insert after New list.Node<Obj>( mynode.NextNode(), mynode, insertdata) Endif mynode = mynode.NextNode() Wend Nodes can remove a value from a list, although be sure to be done with that node before you remove it: Local mynode:list.Node<Obj> = mylist.FirstNode() Local removenode:list.Node<Obj> While mynode If mynode.Value.x = 2 ''remove removenode = mynode Endif mynode = mynode.NextNode() removenode.Remove() Wend