package dendron.tree;

import dendron.machine.Machine;

import java.util.LinkedList;

import java.util.List;

/**

* @author Liang,Yu(yxl5521)

*/

public class Variable implements ExpressionNode{

private String name;

private List<Machine.Instruction> list;

/**

* Set the name of this new Variable.

* @param name the name of this variable

*/

public Variable(String name){

this.name=name;

this.list=new LinkedList<>();

}

/**

* Print on standard output the Variable's name

*/

public void infixDisplay(){

System.out.print(name);

}

/**

* Evaluate a variable by fetching its values.

* @param symTab symbol table, if needed, to fetch variable values

* @return this variable's current value in the symbol table

*/

public int evaluate(java.util.Map<String,Integer> symTab){

return symTab.get(name);

}

/**

* Emit a LOAD instruction that pushes the Variable's value onto the stack.

* @return a list containing a single LOAD instruction

*/

public java.util.List<Machine.Instruction> emit(){

Machine.Load load = new Machine.Load(name);

list.add(load);

return list;

}

}