Improved GC and added a GC pass to the shell

.gitignore

@@ -0,0 +1 @@
+a.out

crank.h

@@ -289,6 +289,26 @@ public:
 
 	void collect()
 	{
+		auto elems = &elements;
+		while(elems->ptr)
+		{
+			auto elems_after = &(elems->ptr->next);
+			while(elems_after->ptr)
+			{
+				if(
+					elems->ptr->data.first == elems_after->ptr->data.first
+				)
+				{
+					*elems_after = std::move(elems_after->ptr->next);
+				}
+				else
+				{
+					elems_after = &(elems_after->ptr->next);
+				}
+			}
+			elems = &(elems->ptr->next);
+		}
+
 		auto cps = &copies;
 		while(cps->ptr)
 		{

main.cpp

@@ -30,6 +30,7 @@ int main()
 		for(auto c : ret)
 			std::cout<<c;
 		std::cout<<std::endl<<"> ";
+		ctx.collect();
 	}
 }