/* function types for tiger  */
/* Chuck Liang */

package Types;

public class FUNC extends Type
{
  public tlist domain;  // parameter types
  public Type range;    // return type
  FUNC(tlist d, Type r)  { domain = d;  range = r; }

  public boolean coerceTo(Type ti)
   { if (!(ti.actual() instanceof FUNC))return false;
     FUNC t = (FUNC) ti;
     return (coerceDomain(t.domain) && coerceRange(t.range));
   }
	      

  public boolean coerceDomain(tlist args)  // compare parameter types
   { if (args.length() != domain.length()) return false;
     boolean answer = true;
     tlist current1 = domain;
     tlist current2 = args;
     while (current1 != null)
	{ answer = answer && (current1.head.coerceTo(current2.head));
          current1 = current1.tail;  
          current2 = current2.tail;
        }
     return answer;
   }

  public boolean coerceRange(Type t)      // compare return type
   { return range.coerceTo(t); }


}// end of class FUNC