/** Saves a copy of the item on the stack at depth to var. */
Node saveCopy(Symbol var, int depth);

/** Loads var on the stack at delve. */
Node loadTemp(Symbol var, int delve);

/** Stores var from the stack at delve. */
Node storeTemp(Symbol var, int delve);

Node virtualNode(int op, Symbol s, int depth);

/** Returns a STACKP node, for TOS */ 
Node TOS(Symbol s, int depth);

Node dropTop(int temp, int depth);

Node storeTop(int temp, int depth);

Node storeToStack(Symbol s, int index, int depth);

void popTemp(Symbol temp, Block b);

void pushTemp(Symbol temp, Block b);

/** Returns a STACKP node. 
  *  var - The variable.
  *  index - Location on stack, 1 is TOS.
  *  depth - Stack depth before this node */
Node stackReg(Symbol var, int index, int depth);

Node dummyToStack(Symbol s, int index);