SE 498 Sample Code

todo.zip: Rails project from CoffeeScript Programming with jQuery, Rails, and Node.js - illustrates using jQuery with Rails 4.2.1 and Ruby 2.0.0.
phones.rb: simple phone book based on arrays
revised-phones.rb: revised phone book using hash tables
gpa.rb: computing semester gpa from input strings; illustrates string and array processing.
csv-select: Ruby program to select specified field from input containing comma-separated values. This is based on a state machine (also available in visio format). The file data.csv can be used for testing. This also illustrates command-line argument processing (see main) and making a stand-alone program (see the first line in the file).
hicscore.rb: program to process CS 143 server data and compute lab scores (not quite complete - does not handle grace dates). Running it on lab0.dat by the command
```
        ruby hicscore.rb <lab0.dat
```
gives the output in lab0.out.

Overloading operator ==:

        class Pair
          attr_reader :x, :y
          attr_writer :x, :y
          # two Pairs are defined to be the same if their products are:
          def ==(other)
            @x * @y == other.x * other.y
          end
        end

Using it:

        irb(main):042:0> a = Pair.new; a.x = 5; a.y = 6
        => 6
        irb(main):043:0> b = Pair.new; b.x = 3; b.y = 10
        => 10
        irb(main):044:0> a == b
        => true
        irb(main):045:0> b.y = 9
        => 9
        irb(main):046:0> a == b
        => false

lazy.rb: Lazy evaluation:

        p = Promise.new { puts '>>>> evaluating <<<<'; 5 * 5 }
        p
        p.force
        p.force
        p.to_s

karel-formatter.rb: uses recursive descent to format (simplified) Karel programs. See the source code for the syntax. A sample input file: karel-test.txt.