Ensure only PEnv can create new symbols (and thus they are unique).

git-svn-id: http://svn.drobilla.net/resp/tuplr@63 ad02d1e2-f140-0410-9f75-f8b11f17cedd

1 files changed, 2 insertions, 1 deletions

diff --git a/tuplr.hpp b/tuplr.hpp
index 87cc743..7c28112 100644
--- a/tuplr.hpp
+++ b/tuplr.hpp
@@ -111,11 +111,12 @@ struct ASTLiteral : public AST {
 
 /// Symbol, e.g. "a"
 struct ASTSymbol : public AST {
-	ASTSymbol(const string& s, Cursor c=Cursor()) : loc(c), cppstr(s) {}
 	bool   operator==(const AST& rhs) const { return this == &rhs; }
 	string str()                      const { return cppstr; }
 	CValue compile(CEnv& cenv);
 private:
+	friend class PEnv;
+	ASTSymbol(const string& s, Cursor c=Cursor()) : loc(c), cppstr(s) {}
 	Cursor       loc;
 	const string cppstr;
 };