Lab 8: Domain-Specific Language Pattern

Objectives

During this lab session:

Students will write and test Ruby code that implements the Domain-Specific Language (DSL) pattern.

This activity helps students develop the following skills, values and attitudes: ability to analyze and synthesize, capacity for identifying and solving problems, and efficient use of computer systems.

Activity Description

IMPORTANT NOTE: The lab activities can be developed individually or in pairs. The lab report must be developed individually.

Create a folder called dsl. Inside this folder, create two files called: jankenpon.rb and tc_jankenpon.rb.

All Ruby source files must start with a comment containing the lab’s title, date, and the authors’ personal information. For example:
```
# Lab 8: Domain-Specific Language Pattern
# Date: 3-Apr-2013
# Authors:
# 456654  Thursday Rubinstein 
# 1160611 Anthony Stark
```
In the jankenpon.rb source file, implement an internal Domain-Specific Language (DSL) that allows you to see the results of a Rock-Paper-Scissors-Lizard-Spock (a.k.a. Jan-ken-pon five-weapon expansion) hand game.

The rules of this game are as follows:
- Scissors cut Paper
- Paper covers Rock
- Rock crushes Lizard
- Lizard poisons Spock
- Spock smashes Scissors
- Scissors decapitate Lizard
- Lizard eats Paper
- Paper disproves Spock
- Spock vaporizes Rock
- Rock crushes Scissors
These rules are summarized in the following image:

Your DSL should support five “literal” values: Rock, Paper, Scissors, Lizard, and Spock. These values can be combined with the plus (+), minus (-) and parenthesis operators to conform complex expressions. Let A and B be expressions. The expression “A + B” returns the winner between A and B, while “A - B” returns the loser. Additionally, whenever the + and - operators execute the rule being applied is displayed on the standard output. Precedence and associativity of the operators follow Ruby’s rules.

For example, this DSL code:
```
show Spock - (Lizard + Paper)
```
should display the following:
```
Lizard eats Paper (winner Lizard)
Lizard poisons Spock (loser Spock)
Result = Spock
```
The show command is responsible for the last line of the output, showing the result of the expression it takes as input.

Notice that the result and effect of “A + B” are the same as “B + A”. The same is true for “A - B” and “B - A”.

It’s possible to have a tie. This code:
```
show Spock + Spock
```
should generate this output:
```
Spock tie (winner Spock)
Result = Spock
```

The following unit tests verify the correct behavior of your DSL. Place the test class in the tc_jankenpon.rb source file.

# File: tc_jankenpon.rb

require 'test/unit'
require 'stringio'
require 'jankenpon'

class JakenponTest < Test::Unit::TestCase

  def setup
    @old_stdout = $stdout
    @out = $stdout = StringIO.new
  end

  def teardown
    $stdout = @old_stdout
  end

  def test_simple_cases_plus
    assert_equal Scissors, (Scissors + Paper)
    assert_equal Scissors, (Paper + Scissors)
    assert_equal Paper,    (Paper + Rock)
    assert_equal Paper,    (Rock + Paper)
    assert_equal Rock,     (Rock + Lizard)
    assert_equal Rock,     (Lizard + Rock)
    assert_equal Lizard,   (Lizard + Spock)
    assert_equal Lizard,   (Spock + Lizard)
    assert_equal Spock,    (Spock + Scissors)
    assert_equal Spock,    (Scissors + Spock)
    assert_equal Scissors, (Scissors + Lizard)
    assert_equal Scissors, (Lizard + Scissors)
    assert_equal Lizard,   (Lizard + Paper)
    assert_equal Lizard,   (Paper + Lizard)
    assert_equal Paper,    (Paper + Spock)
    assert_equal Paper,    (Spock + Paper)
    assert_equal Spock,    (Spock + Rock)
    assert_equal Spock,    (Rock + Spock)
    assert_equal Rock,     (Rock + Scissors)
    assert_equal Rock,     (Scissors + Rock)
    assert_equal Scissors, (Scissors + Scissors)
    assert_equal Paper,    (Paper + Paper)
    assert_equal Rock,     (Rock + Rock)
    assert_equal Lizard,   (Lizard + Lizard)
    assert_equal Spock,    (Spock + Spock)
  end

  def test_simple_cases_minus
    assert_equal Paper,    (Scissors - Paper)
    assert_equal Paper,    (Paper - Scissors)
    assert_equal Rock,     (Paper - Rock)
    assert_equal Rock,     (Rock - Paper)
    assert_equal Lizard,   (Rock - Lizard)
    assert_equal Lizard,   (Lizard - Rock)
    assert_equal Spock,    (Lizard - Spock)
    assert_equal Spock,    (Spock - Lizard)
    assert_equal Scissors, (Spock - Scissors)
    assert_equal Scissors, (Scissors - Spock)
    assert_equal Lizard,   (Scissors - Lizard)
    assert_equal Lizard,   (Lizard - Scissors)
    assert_equal Paper,    (Lizard - Paper)
    assert_equal Paper,    (Paper - Lizard)
    assert_equal Spock,    (Paper - Spock)
    assert_equal Spock,    (Spock - Paper)
    assert_equal Rock,     (Spock - Rock)
    assert_equal Rock,     (Rock - Spock)
    assert_equal Scissors, (Rock - Scissors)
    assert_equal Scissors, (Scissors - Rock)
    assert_equal Scissors, (Scissors - Scissors)
    assert_equal Paper,    (Paper - Paper)
    assert_equal Rock,     (Rock - Rock)
    assert_equal Lizard,   (Lizard - Lizard)
    assert_equal Spock,    (Spock - Spock)
  end

  def test_dsl_1
    #---------
    show Spock
    #---------
    assert_equal "Result = Spock\n", @out.string
  end

  def test_dsl_2
    #------------------
    show Spock + Lizard
    #------------------
    assert_equal "Lizard poisons Spock (winner Lizard)\n" \
                 "Result = Lizard\n", \
                 @out.string
  end

  def test_dsl_3
    #------------------
    show Spock - Lizard
    #------------------
    assert_equal "Lizard poisons Spock (loser Spock)\n" \
                 "Result = Spock\n", \
                 @out.string
  end

  def test_dsl_4
    #-------------------------
    show Spock + Lizard + Rock
    #-------------------------
    assert_equal "Lizard poisons Spock (winner Lizard)\n" \
                 "Rock crushes Lizard (winner Rock)\n" \
                 "Result = Rock\n", \
                 @out.string
  end

  def test_dsl_5
    #---------------------------
    show Spock + (Lizard + Rock)
    #---------------------------
    assert_equal "Rock crushes Lizard (winner Rock)\n" \
                 "Spock vaporizes Rock (winner Spock)\n" \
                 "Result = Spock\n", \
                 @out.string
  end

  def test_dsl_6
    #--------------------------------------------
    show Rock + Paper + Scissors + Lizard + Spock
    #--------------------------------------------
    assert_equal "Paper covers Rock (winner Paper)\n" \
                 "Scissors cut Paper (winner Scissors)\n" \
                 "Scissors decapitate Lizard (winner Scissors)\n" \
                 "Spock smashes Scissors (winner Spock)\n" \
                 "Result = Spock\n", \
                 @out.string
  end

  def test_dsl_7
    #--------------------------------------------
    show Rock - Paper - Scissors - Lizard - Spock
    #--------------------------------------------
    assert_equal "Paper covers Rock (loser Rock)\n" \
                 "Rock crushes Scissors (loser Scissors)\n" \
                 "Scissors decapitate Lizard (loser Lizard)\n" \
                 "Lizard poisons Spock (loser Spock)\n" \
                 "Result = Spock\n", \
                 @out.string
  end

  def test_dsl_8
    #-------------------------------------------------
    show((Rock + Paper) - (Scissors + Lizard) + Spock)
    #-------------------------------------------------
    assert_equal "Paper covers Rock (winner Paper)\n" \
                 "Scissors decapitate Lizard (winner Scissors)\n" \
                 "Scissors cut Paper (loser Paper)\n" \
                 "Paper disproves Spock (winner Paper)\n" \
                 "Result = Paper\n", \
                 @out.string
  end

  def test_dsl_9
    #---------------------------------------------
    show Paper + ((Spock + Paper) - Lizard + Rock)
    #---------------------------------------------
    assert_equal "Paper disproves Spock (winner Paper)\n" \
                 "Lizard eats Paper (loser Paper)\n" \
                 "Paper covers Rock (winner Paper)\n" \
                 "Paper tie (winner Paper)\n" \
                 "Result = Paper\n", \
                 @out.string
  end
  
end

Deliverables

To hand in your individual lab work, follow these instructions.

Write your lab report in English according to the specified guidelines. Name your AsciiDoc source file lab8_report_A0MMMMMMM.txt, where A0MMMMMMM is your student ID. From your AsciiDoc source, generate the corresponding HTML file. That file should be called lab8_report_A0MMMMMMM.html. Place these two files in the dsl directory.
Create a tarball file with the full contents of the dsl directory. Call this file dsl.tgz. From a terminal, you can use the following command to create this file (make sure to run it at the same level where the dsl folder resides):
```
tar czf dsl.tgz dsl
```
Using the Online Assignment Delivery System (SETA), deliver the tarball file.

Due date is Tuesday, April 9.

Evaluation

This activity will be evaluated using the following criteria:

50%	Implementation of functional requirements.
50%	Lab report.
DA	The program and/or report was plagiarized.

Software Design and Architecture

Lab 8: Domain-Specific Language Pattern

Objectives

Activity Description

Deliverables

Evaluation