Add helper functions for making shared pointers to rules

- start work on item set class

src/rules/symbol.cpp

@@ -1,25 +1,23 @@
 #include "symbol.h"
+#include "blank.h"
 #include "transition_map.h"
 
 namespace tree_sitter  {
     namespace rules {
-        Symbol::Symbol(int id) : id(id) {};
+        Symbol::Symbol(const std::string &name) : name(name) {};
+        Symbol::Symbol(const char *name) : name(name) {};
 
         TransitionMap<Rule> Symbol::transitions() const {
-            return TransitionMap<Rule>({ copy() }, { new Blank() });
+            return TransitionMap<Rule>({ rule_ptr(new Symbol(name)) }, { rule_ptr(new Blank()) });
         }
         
         bool Symbol::operator==(const Rule &rule) const {
             const Symbol *other = dynamic_cast<const Symbol *>(&rule);
-            return (other != NULL) && (other->id == id);
-        }
-        
-        Symbol * Symbol::copy() const {
-            return new Symbol(id);
+            return (other != NULL) && (other->name == name);
         }
         
         std::string Symbol::to_string() const {
-            return std::to_string(id);
-        }        
+            return name;
+        }
     }
 }