1 files changed, 12 insertions, 0 deletions
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 28049bb0d638..2e26d50817fb 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -336,4 +336,16 @@ string ExprLambda::showNamePos()
 }
 
 
+
+/* Symbol table. */
+
+size_t SymbolTable::totalSize() const
+{
+    size_t n = 0;
+    foreach (Symbols::const_iterator, i, symbols)
+        n += i->size();
+    return n;
+}
+
+
 }