Golang ordered sets using container/list

ordered_set.go

package main

import "container/list"

// ListUnion merges the second list into the first list while retaining order.
func ListUnion(dst *list.List, src *list.List) {
	for e1, e2 := src.Front(), dst.Front(); e2 != nil; {
		if e1 == nil {
			dst.PushBack(e2.Value)
			e2.Next()
			continue
		}
		v1, v2 := e1.Value.(uint), e2.Value.(uint)
		if v1 == v2 {
			e2.Next()
		} else if v1 < v2 {
			e1.Next()
		} else {
			dst.InsertBefore(v2, e1)
		}
	}
}

// Convert list to uint slice.
func toSlice(l *list.List) []uint {
	output := make([]uint, 0, l.Len())
	for ptr := l.Front(); ptr != nil; ptr = ptr.Next() {
		output = append(output, ptr.Value.(uint))
	}
	return output
}