add update statement

table.go

@@ -9,6 +9,7 @@ import (
 var (
 	insertTableRegexp = regexp.MustCompile("^into ([^ ]+)( (as) ([^ ]+))?$")
 	selectTableRegexp = regexp.MustCompile("^(from|left join|inner join|right join) ([^ ]+)( (as) ([^ ]+))?( (on) ([^ ]+) (=|!=|>|>=|<|<=) ([^ ]+)( (and) ([^ ]+) (=|!=|>|>=|<|<=) ([^ ]+))*)?$")
+	updateTableRegexp = regexp.MustCompile("^([^ ]+)( (as) ([^ ]+))?$")
 )
 
 type InsertTable string
@@ -120,3 +121,31 @@ func RightJoin(def string) SelectTable {
 
 	return SelectTable(fmt.Sprintf("right join %s", def))
 }
+
+type UpdateTable string
+
+func (t UpdateTable) IsValid() bool {
+	return insertTableRegexp.MatchString(string(t))
+}
+
+func (t UpdateTable) Parse() (table, as string, ok bool) {
+	if insertTableRegexp.MatchString(string(t)) {
+		ok = true
+
+		result := insertTableRegexp.FindAllStringSubmatch(string(t), -1)
+
+		for _, r := range result {
+			table = r[1]
+
+			if r[3] == "as" {
+				as = r[4]
+			}
+		}
+	}
+
+	return
+}
+
+func (t UpdateTable) String() string {
+	return string(t)
+}