1 files changed, 150 insertions, 0 deletions
diff --git a/listbox.go b/listbox.go
new file mode 100644
index 0000000..774f553
--- /dev/null
+++ b/listbox.go
@@ -0,0 +1,150 @@
+// 14 february 2014
+
+package ui
+
+import (
+	"fmt"
+)
+
+// A Listbox is a vertical list of items, of which either at most one or any number of items can be selected at any given time.
+// On creation, no item is selected.
+// For information on scrollbars, see "Scrollbars" in the Overview.
+// Due to implementation issues, the presence of horizontal scrollbars is currently implementation-defined.
+type Listbox struct {
+	created   bool
+	sysData   *sysData
+	initItems []string
+}
+
+func newListbox(multiple bool, items ...string) (l *Listbox) {
+	l = &Listbox{
+		sysData:   mksysdata(c_listbox),
+		initItems: items,
+	}
+	l.sysData.alternate = multiple
+	return l
+}
+
+// NewListbox creates a new single-selection Listbox with the given items loaded initially.
+func NewListbox(items ...string) *Listbox {
+	return newListbox(false, items...)
+}
+
+// NewMultiSelListbox creates a new multiple-selection Listbox with the given items loaded initially.
+func NewMultiSelListbox(items ...string) *Listbox {
+	return newListbox(true, items...)
+}
+
+// Append adds items to the end of the Listbox's list.
+// Append will panic if something goes wrong on platforms that do not abort themselves.
+func (l *Listbox) Append(what ...string) {
+	if l.created {
+		for _, s := range what {
+			l.sysData.append(s)
+		}
+		return
+	}
+	l.initItems = append(l.initItems, what...)
+}
+
+// InsertBefore inserts a new item in the Listbox before the item at the given position. It panics if the given index is out of bounds.
+// InsertBefore will also panic if something goes wrong on platforms that do not abort themselves.
+func (l *Listbox) InsertBefore(what string, before int) {
+	var m []string
+
+	if l.created {
+		if before < 0 || before >= l.sysData.len() {
+			goto badrange
+		}
+		l.sysData.insertBefore(what, before)
+		return
+	}
+	if before < 0 || before >= len(l.initItems) {
+		goto badrange
+	}
+	m = make([]string, 0, len(l.initItems)+1)
+	m = append(m, l.initItems[:before]...)
+	m = append(m, what)
+	l.initItems = append(m, l.initItems[before:]...)
+	return
+badrange:
+	panic(fmt.Errorf("index %d out of range in Listbox.InsertBefore()", before))
+}
+
+// Delete removes the given item from the Listbox. It panics if the given index is out of bounds.
+func (l *Listbox) Delete(index int) {
+	if l.created {
+		if index < 0 || index >= l.sysData.len() {
+			goto badrange
+		}
+		l.sysData.delete(index)
+		return
+	}
+	if index < 0 || index >= len(l.initItems) {
+		goto badrange
+	}
+	l.initItems = append(l.initItems[:index], l.initItems[index+1:]...)
+	return
+badrange:
+	panic(fmt.Errorf("index %d out of range in Listbox.Delete()", index))
+}
+
+// Selection returns a list of strings currently selected in the Listbox, or an empty list if none have been selected. This list will have at most one item on a single-selection Listbox.
+func (l *Listbox) Selection() []string {
+	if l.created {
+		return l.sysData.selectedTexts()
+	}
+	return nil
+}
+
+// SelectedIndices returns a list of the currently selected indexes in the Listbox, or an empty list if none have been selected. This list will have at most one item on a single-selection Listbox.
+func (l *Listbox) SelectedIndices() []int {
+	if l.created {
+		return l.sysData.selectedIndices()
+	}
+	return nil
+}
+
+// Len returns the number of items in the Listbox.
+//
+// On platforms for which this function may return an error, it panics if one is returned.
+func (l *Listbox) Len() int {
+	if l.created {
+		return l.sysData.len()
+	}
+	return len(l.initItems)
+}
+
+func (l *Listbox) make(window *sysData) (err error) {
+	err = l.sysData.make(window)
+	if err != nil {
+		return err
+	}
+	for _, s := range l.initItems {
+		l.sysData.append(s)
+	}
+	l.created = true
+	return nil
+}
+
+func (l *Listbox) allocate(x int, y int, width int, height int, d *sysSizeData) []*allocation {
+	return []*allocation{&allocation{
+		x:       x,
+		y:       y,
+		width:   width,
+		height:  height,
+		this:		l,
+	}}
+}
+
+func (l *Listbox) preferredSize(d *sysSizeData) (width int, height int) {
+	return l.sysData.preferredSize(d)
+}
+
+func (l *Listbox) commitResize(a *allocation, d *sysSizeData) {
+	l.sysData.commitResize(a, d)
+}
+
+func (l *Listbox) getAuxResizeInfo(d *sysSizeData) {
+	l.sysData.getAuxResizeInfo(d)
+}