about = <<"STUFF"
This example defines a class with accessors, some default
and some none-default parameters to its constructor. There's
also a demonstration of a comparator method that return one
of two objects it compares.

Below, you'll find a sample program which runs when this class
file is called on its own, but is skipped when this file is
included in another application - an ideal test harness.

STUFF

class Train
attr_accessor :uclass
attr_accessor :nstaff

def initialize(ncars,uclass="125",nstaff=3)
        @length = ncars
        @uclass = uclass
        @nstaff = nstaff
        end

def getdftdesiredlength()
        return @length-1
        end

def getspc()
        (@nstaff*1.0)/@length
        end

def betterstaffed(second)
        # First input - function call
        # the "self" can be omitted (job protection coding)
        first_val = self.getspc()
        # Second input - call the method
        second_val = second.getspc()
        # return an OBJECT - not the best ratio
        # that way - you can report what you want!
        first_val < second_val ? second : self
        end
end

# Test Harness!

if __FILE__ == $0

        morning = Train.new(2,"150",2)
        diversion = Train.new(7)
        evening = Train.new(1,"153",2)
        # Next line - pretty awful if it expects an int!
        late = Train.new("Usually 1, sometimes 2")

# Following will FAIL - Constructor needs 1 to 3 params
# in this case!
# ghost = Train.new

        puts morning.nstaff
        puts evening.nstaff

        puts morning.getdftdesiredlength
        puts evening.getdftdesiredlength

        puts morning.uclass()
        puts evening.uclass()

        puts morning.getspc
        puts evening.getspc

# How to call a comparator in Ruby
        service1 = morning.betterstaffed(evening)
        service2 = evening.betterstaffed(morning)
# tested both ways to test both bits of logic!

        print service1.uclass()," - ",service2.uclass(),"\n"

        end

result = <<"EXAMPLE"

Sample output:

Dorothy:rn grahamellis$ ruby train.rb
2
2
1
0
150
153
1.0
2.0
153 - 153
Dorothy:rn grahamellis$

EXAMPLE