Another constructs a Quantity out of just a String:

class Quantity

{

double multiplier;

StringList numerator;

StringList denominator;

 

.... other constructors  for Quantity ....

 

Quantity(String unit) 		// constructor head

  {				// constructor body

  this.multiplier = 1.0;

  this.numerator = Stringlist.cons(unit, Stringlist.nil);

  this.denominator = Stringlist.nil;

  }

 

.... other constructors and methods for Quantity ....

}

 

Notice that outside the class Stringlist we must qualify the value or method by prefixing the classname: Stringlist.cons