case FuncName.CONTAINS: default: throw new UnsupportedException("Some functions are not supported");
case FuncName.CONTAINS:	throw new UnsupportedException("Some functions are not supported"); default: if (isNumerical()){ double d = evalNumber(vn); if (d==0 || d!=d) return false; return true; }else{ return evalString(vn).length()!=0; }
	public boolean evalBoolean(VTDNav vn){	  	  switch(opCode){			case FuncName.TRUE: if (argCount()!=0){									throw new IllegalArgumentException("true() doesn't take any argument");								}								return true;						case FuncName.FALSE:if (argCount()!=0){									throw new IllegalArgumentException("false() doesn't take any argument");								}								return false;				case FuncName.BOOLEAN: if (argCount()!=1){										throw new IllegalArgumentException("boolean() doesn't take any argument");								   }									return argumentList.e.evalBoolean(vn);				case FuncName.NOT:	if (argCount()!=1){										throw new IllegalArgumentException("not() doesn't take any argument");			   					}								return !argumentList.e.evalBoolean(vn);			case FuncName.CONTAINS:				default: throw new UnsupportedException("Some functions are not supported");		  }	}