1 files changed, 21 insertions, 0 deletions
diff --git a/bnf/common.hpp b/bnf/common.hpp
new file mode 100644
index 00000000..2a74a7ba
--- /dev/null
+++ b/bnf/common.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+namespace std {
+
+template <typename T>
+inline ::std::ostream& operator<<(::std::ostream& os, const ::std::vector<T>& v) {
+    if( v.size() > 0 )
+    {
+        bool is_first = true;
+        for( const auto& i : v )
+        {
+            if(!is_first)
+                os << ", ";
+            is_first = false;
+            os << i;
+        }
+    }
+    return os;
+}
+
+};