Implement skipper interface

mongox/query/compose.go

@@ -45,6 +45,8 @@ func applyLimits(q *Query, f interface{}) bool {
 		q.limiter = f
 	case Sorter:
 		q.sorter = f
+	case Skipper:
+		q.skipper = f
 	default:
 		return false
 	}

mongox/query/query.go

@@ -11,6 +11,7 @@ type Query struct {
 	m       bson.M
 	limiter Limiter
 	sorter  Sorter
+	skipper Skipper
 }
 
 // And function pushes the elem query to the $and array of the query
@@ -52,6 +53,16 @@ func (q *Query) Sorter() interface{} {
 	return q.sorter.Sort()
 }
 
+// Skipper is a skipper for a query
+func (q *Query) Skipper() *int64 {
+
+	if q.skipper == nil {
+		return nil
+	}
+
+	return q.skipper.Skip()
+}
+
 // Empty checks the query for any content
 func (q *Query) Empty() bool {
 

mongox/query/skip.go

@@ -0,0 +1,22 @@
+package query
+
+// Skipper is a filter to skip the result
+type Skipper interface {
+	Skip() *int64
+}
+
+// Skip is a simple implementation of the Skipper filter
+type Skip int64
+
+var _ Skipper = Skip(0)
+
+// Skip returns a skip number
+func (l Skip) Skip() *int64 {
+
+	lim := int64(l)
+	if lim <= 0 {
+		return nil
+	}
+
+	return &lim
+}