package nl.bluering;
import java.io.*;
import java.util.*;
import java.math.BigInteger;


public abstract class Interpreter
{
 RootLib root;
 
 static Class numberclass=new Integer(0).getClass();
 static Class stringclass="".getClass();
 
 
 Hashtable libdef=new Hashtable();
 
 
 public void mount(functionpointer f)
 {functionpointer olddef=getfp(f.getprototype());
  if (olddef!=null&&!olddef.isnormal())
  {System.out.println("mount failed");
   return;
  }
  if(f.isnormal())  
   olddef=getfp(f.getprototype(),f.a1class);  
  if(olddef!=null)
  {System.out.println("mount of normal failed");
   return;
  }
  mount2(f);
 }
 
 private void mount2(functionpointer f)
 {
  
  if (f.isnormal())
  {
  // System.out.println("mount "+f.getextendedprototype()+" : "+f);
   libdef.put(f.getextendedprototype(),f);
  }
  //System.out.println("mount "+f.getprototype()+" : "+f);
  libdef.put(f.getprototype(),f);
  if(root!=null&&root!=this)
  	root.mount(f);
 }
 	
 abstract void mountall();
 
 abstract Variable run(Variable result,Expression e,int index) 
  throws Exception;
 
 Interpreter()
 {}
 
 void installin(RootLib r)
 {root=r;
  mountall(); 
 }
 
 void mnormal(String name,int arity,int index,String help,Class c)
 {mount(new functionpointer(name,arity,this,index,help,c));}
 void mspecial(String name,int arity,int index,String help)
 {mount(new functionpointer(name,arity,this,index,help));}
  
 static File getfile(Variable result)
 {
  Object o=result.getobject();
  if(o instanceof File)
  	return (File)o;
  return null;
 }
 static ExpParser getexpparser(Variable result)
 {
  Object o=result.getobject();
  if(o instanceof ExpParser)
  	return (ExpParser)o;
  return null;
 }
 static ExpWriter getexpwriter(Variable result)
 {
  Object o=result.getobject();
  if(o instanceof ExpWriter)
  	return (ExpWriter)o;
  return null;
 }
 static RandomAccessFile getraf(Variable result)
 {
  Object o=result.getobject();
  if(o instanceof RandomAccessFile)
  	return (RandomAccessFile)o;
  return null;
 }
 static byte[] getba(Variable result)
 {
  Object o=result.getobject();
  if(o instanceof byte[])
  	return (byte[])o;
  return null;
 }	
  
 BigInteger getbi(Variable result,Expression e,int pos)
 throws Exception
 {Object o1=root.run(result,e.get(pos)).getobject();
  if(o1 instanceof String) o1=new BigInteger((String)o1);
  if(o1==null || !(o1 instanceof BigInteger))
   throw new Exception("BigInteger expected:"+o1.getClass().getName());
  return (BigInteger)o1; 
 } 


 functionpointer getfp(String name,int arity)
 {functionpointer result=getfp(functionpointer.makeprototype(name,arity));
  if(result==null&&arity>0) 
   result=getfp(functionpointer.makeprototype(name,100));
  return result;
 }

/**
* get the functionpointer
* @param prototype a (not-extended) prototype 
* @return a functionpointer if there is any
*/

 functionpointer getfp(String prototype)
 {return (functionpointer)libdef.get(prototype);
 }

 functionpointer getfp(String name,int arity,Class c)
 {functionpointer result=getfp(functionpointer.makeprototype(name,arity),c);
  if(result==null&&arity>0) 
   result=getfp(functionpointer.makeprototype(name,100),c);
  return result;
 }

 
/**
* get the functionpointer. This only gets normal functions. You 
* should try the other getfp first to also find special functions.
* @param prototype a (not-extended) prototype 
* @param c the class it must work on
* @return a functionpointer if there is any for that specific class
*/ 
 functionpointer getfp(String prototype,Class c1)
 {
  functionpointer result=null;
  Class c=c1;
  while (c!=null)
  {
   result=(functionpointer)libdef.get(
    functionpointer.extendprototype(prototype,c)
   );
   if(result!=null)
   	return result;
   c=Variable.getsuperclass(c);
  }
  if (c1==stringclass)
   result=(functionpointer)
      libdef.get(functionpointer.extendprototype(prototype,numberclass));
  else if (c1==numberclass)
   result=(functionpointer)
      libdef.get(functionpointer.extendprototype(prototype,stringclass));
 
  return result;
 }

  
}