list, ring and sort from Go source converted into gotemplates

list/example_test.go

@@ -0,0 +1,30 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package list_test
+
+import (
+	"container/list"
+	"fmt"
+)
+
+func Example() {
+	// Create a new list and put some numbers in it.
+	l := list.New()
+	e4 := l.PushBack(4)
+	e1 := l.PushFront(1)
+	l.InsertBefore(3, e4)
+	l.InsertAfter(2, e1)
+
+	// Iterate through list and and print its contents.
+	for e := l.Front(); e != nil; e = e.Next() {
+		fmt.Println(e.Value)
+	}
+
+	// Output:
+	// 1
+	// 2
+	// 3
+	// 4
+}

list/list.go

@@ -0,0 +1,202 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// Modified into a gotemplate by Nick Craig-Wood <nick@craig-wood.com>
+
+// Package list implements a doubly linked list.
+//
+// To iterate over a list (where l is a *List):
+//	for e := l.Front(); e != nil; e = e.Next() {
+//		// do something with e.Value
+//	}
+//
+package list
+
+// template type List(A)
+type A int
+
+// ListElement is an element of a linked list.
+type ListElement struct {
+	// Next and previous pointers in the doubly-linked list of elements.
+	// To simplify the implementation, internally a list l is implemented
+	// as a ring, such that &l.root is both the next element of the last
+	// list element (l.Back()) and the previous element of the first list
+	// element (l.Front()).
+	next, prev *ListElement
+
+	// The list to which this element belongs.
+	list *List
+
+	// The value stored with this element.
+	Value A
+}
+
+// Next returns the next list element or nil.
+func (e *ListElement) Next() *ListElement {
+	if p := e.next; p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+// Prev returns the previous list element or nil.
+func (e *ListElement) Prev() *ListElement {
+	if p := e.prev; p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+// List represents a doubly linked list.
+// The zero value for List is an empty list ready to use.
+type List struct {
+	root ListElement // sentinel list element, only &root, root.prev, and root.next are used
+	len  int         // current list length excluding (this) sentinel element
+}
+
+// Init initializes or clears list l.
+func (l *List) Init() *List {
+	l.root.next = &l.root
+	l.root.prev = &l.root
+	l.len = 0
+	return l
+}
+
+// New returns an initialized list.
+func NewList() *List { return new(List).Init() }
+
+// Len returns the number of elements of list l.
+func (l *List) Len() int { return l.len }
+
+// Front returns the first element of list l or nil
+func (l *List) Front() *ListElement {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.next
+}
+
+// Back returns the last element of list l or nil.
+func (l *List) Back() *ListElement {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.prev
+}
+
+// lazyInit lazily initializes a zero List value.
+func (l *List) lazyInit() {
+	if l.root.next == nil {
+		l.Init()
+	}
+}
+
+// insert inserts e after at, increments l.len, and returns e.
+func (l *List) insert(e, at *ListElement) *ListElement {
+	n := at.next
+	at.next = e
+	e.prev = at
+	e.next = n
+	n.prev = e
+	e.list = l
+	l.len++
+	return e
+}
+
+// insertValue is a convenience wrapper for insert(&ListElement{Value: v}, at).
+func (l *List) insertValue(v A, at *ListElement) *ListElement {
+	return l.insert(&ListElement{Value: v}, at)
+}
+
+// remove removes e from its list, decrements l.len, and returns e.
+func (l *List) remove(e *ListElement) *ListElement {
+	e.prev.next = e.next
+	e.next.prev = e.prev
+	e.next = nil // avoid memory leaks
+	e.prev = nil // avoid memory leaks
+	e.list = nil
+	l.len--
+	return e
+}
+
+// Remove removes e from l if e is an element of list l.
+// It returns the element value e.Value.
+func (l *List) Remove(e *ListElement) A {
+	if e.list == l {
+		// if e.list == l, l must have been initialized when e was inserted
+		// in l or l == nil (e is a zero ListElement) and l.remove will crash
+		l.remove(e)
+	}
+	return e.Value
+}
+
+// Pushfront inserts a new element e with value v at the front of list l and returns e.
+func (l *List) PushFront(v A) *ListElement {
+	l.lazyInit()
+	return l.insertValue(v, &l.root)
+}
+
+// PushBack inserts a new element e with value v at the back of list l and returns e.
+func (l *List) PushBack(v A) *ListElement {
+	l.lazyInit()
+	return l.insertValue(v, l.root.prev)
+}
+
+// InsertBefore inserts a new element e with value v immediately before mark and returns e.
+// If mark is not an element of l, the list is not modified.
+func (l *List) InsertBefore(v A, mark *ListElement) *ListElement {
+	if mark.list != l {
+		return nil
+	}
+	// see comment in List.Remove about initialization of l
+	return l.insertValue(v, mark.prev)
+}
+
+// InsertAfter inserts a new element e with value v immediately after mark and returns e.
+// If mark is not an element of l, the list is not modified.
+func (l *List) InsertAfter(v A, mark *ListElement) *ListElement {
+	if mark.list != l {
+		return nil
+	}
+	// see comment in List.Remove about initialization of l
+	return l.insertValue(v, mark)
+}
+
+// MoveToFront moves element e to the front of list l.
+// If e is not an element of l, the list is not modified.
+func (l *List) MoveToFront(e *ListElement) {
+	if e.list != l || l.root.next == e {
+		return
+	}
+	// see comment in List.Remove about initialization of l
+	l.insert(l.remove(e), &l.root)
+}
+
+// MoveToBack moves element e to the back of list l.
+// If e is not an element of l, the list is not modified.
+func (l *List) MoveToBack(e *ListElement) {
+	if e.list != l || l.root.prev == e {
+		return
+	}
+	// see comment in List.Remove about initialization of l
+	l.insert(l.remove(e), l.root.prev)
+}
+
+// PushBackList inserts a copy of an other list at the back of list l.
+// The lists l and other may be the same.
+func (l *List) PushBackList(other *List) {
+	l.lazyInit()
+	for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
+		l.insertValue(e.Value, l.root.prev)
+	}
+}
+
+// PushFrontList inserts a copy of an other list at the front of list l.
+// The lists l and other may be the same.
+func (l *List) PushFrontList(other *List) {
+	l.lazyInit()
+	for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
+		l.insertValue(e.Value, &l.root)
+	}
+}