From 3dd33af2d66785075d1b2f00d9bc0306dceb9005 Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Fri, 11 Apr 2014 23:32:10 +0800
Subject: [PATCH] add SeqFilter

---
 filter.go | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/filter.go b/filter.go
index 072bc589..60caaf29 100644
--- a/filter.go
+++ b/filter.go
@@ -1,6 +1,9 @@
 package core
 
-import "strings"
+import (
+	"fmt"
+	"strings"
+)
 
 // Filter is an interface to filter SQL
 type Filter interface {
@@ -40,3 +43,22 @@ func (i *IdFilter) Do(sql string, dialect Dialect, table *Table) string {
 	}
 	return sql
 }
+
+// SeqFilter filter SQL replace ?, ? ... to $1, $2 ...
+type SeqFilter struct {
+	Prefix string
+	Start  int
+}
+
+func (s *SeqFilter) Do(sql string, dialect Dialect, table *Table) string {
+	segs := strings.Split(sql, "?")
+	size := len(segs)
+	res := ""
+	for i, c := range segs {
+		if i < size-1 {
+			res += c + fmt.Sprintf("%s%v", s.Prefix, i+s.Start)
+		}
+	}
+	res += segs[size-1]
+	return res
+}