Split compose applier

mongox/query/compose.go

@@ -14,7 +14,9 @@ func Compose(filters ...interface{}) *Query {
 
 		ok := false
 		ok = ok || applyBson(q, f)
-		ok = ok || applyLimits(q, f)
+		ok = ok || applyLimit(q, f)
+		ok = ok || applySort(q, f)
+		ok = ok || applySkip(q, f)
 
 		if !ok {
 			panic(errors.InternalErrorf("unknown filter %v", f))
@@ -27,29 +29,43 @@ func Compose(filters ...interface{}) *Query {
 // applyBson is a fallback for a custom bson.M
 func applyBson(q *Query, f interface{}) bool {
 
-	switch f := f.(type) {
-	case bson.M:
+	if f, ok := f.(bson.M); ok {
 		q.And(f)
-	default:
-		return false
+		return true
 	}
 
-	return true
+	return false
 }
 
-// applyLimits extends query with contol functions
-func applyLimits(q *Query, f interface{}) bool {
+// applyLimits extends query with a limiter
+func applyLimit(q *Query, f interface{}) bool {
 
-	switch f := f.(type) {
-	case Limiter:
+	if f, ok := f.(Limiter); ok {
 		q.limiter = f
-	case Sorter:
-		q.sorter = f
-	case Skipper:
-		q.skipper = f
-	default:
+		return true
+	}
+
 	return false
+}
+
+// applySort extends query with a sort rule
+func applySort(q *Query, f interface{}) bool {
+
+	if f, ok := f.(Sorter); ok {
+		q.sorter = f
+		return true
 	}
 
+	return false
+}
+
+// applySkip extends query with a skip number
+func applySkip(q *Query, f interface{}) bool {
+
+	if f, ok := f.(Skipper); ok {
+		q.skipper = f
 		return true
+	}
+
+	return false
 }