Extemely broken, but all the code up to 7.3 should be here, now the refactoring begins to make it C code and not Java code.

expr.c

@@ -1,6 +1,18 @@
 #include "expr.h"
 
-void VisitBinary(struct binary);
+char* Parenthesize(char*, int, ...);
+
+void VisitBinary(struct binary expr) {
+
+}
+
 void VisitGrouping(struct grouping);
 void VisitLiteral(Token);
-void VisitUnary(struct unary);
+void VisitUnary(struct unary);
+
+char* Parenthesize(char* operator, int count, ...) {
+    va_list list;
+    va_start(list, count);
+
+    va_arg(list, Expr);
+}