Optimise HandleInput#interpret method. Update specs and readme

Author: SelenaSmall

README.md

@@ -1,12 +1,7 @@
 # Toy Robot
 Toy robot simulator written in Ruby
 
-## Table of Contents
-1. [Installation](#Installation)
-2. [Usage](#Usage)
-3. [Testing](#Testing)
-4. [Design](#Design)
-5. [Specifications](#Specifications)
+***
 
 ## Installation
 Environment: Built on Mac OSx using Ruby -v 2.4.1
@@ -20,78 +15,77 @@ Clone this Repo
 In root of the app run bundle install
 > $ gem install bundler && bundle install
 
+***
+
 ## Usage
 Run the program from the app root
 > $ toy_robot.rb
-	
+
 Expected terminal output:
 > Options: PLACE X,Y,F; MOVE; LEFT; RIGHT; REPORT; EXIT
 
-Available commands
-| Command  | Description |
-| ------------- | ------------- |
-| PLACE X,Y,F  | Place the robot on the table at coordinates x,y and facing the direction f. Valid x andy values are between 0-4. Valid directions are WEST, NORTH, EAST, SOUTH. Example Input: "PLACE 0,0,NORTH"|
-| MOVE  | Move the robot forward 1 step in the direction it is facing.  |
-| LEFT  | Turn the robot's direction 90 degress to the left. I.e. if the robot is facing NORTH, 1 left turn will turn the robot's direction to WEST.  |
-| RIGHT  | Turn the robot's direction 90 degress to the right. I.e. if the robot is facing NORTH, 1 left turn will turn the robot's direction to EAST.  |
-| REPORT  | Output the current position of the robot. Example Output: "Output: 0,0,NORTH" |
-| EXIT  | Gracefully exit the program.  |
+Commands | Description
+--- | ---
+PLACE X,Y,F | Place the robot on the table at coordinates x,y and facing the direction f. Valid x andy values are between 0-4. Valid directions are WEST, NORTH, EAST, SOUTH. Example Input: "PLACE 0,0,NORTH"
+MOVE | Move the robot forward 1 step in the direction it is facing.
+LEFT | Turn the robot's direction 90 degress to the left. I.e. if the robot is facing NORTH, 1 left turn will turn the robot's direction to WEST.
+RIGHT | Turn the robot's direction 90 degress to the right. I.e. if the robot is facing NORTH, 1 left turn will turn the robot's direction to EAST.
+REPORT | Output the current position of the robot. Example Output: "Output: 0,0,NORTH"
+EXIT | Gracefully exit the program.
+
+***
 
 ## Testing
 Test by running rspec http://rspec.info/ 
 > $ bundle exec rspec
 	
 Expected terminal output:
-> ... ..Output: 0,0,NORTH 
->
-> ... ... ... ...Output: 1,2,NORTH 
+> ... ... ... ... ... .Output: 1,2,NORTH
 >
-> ... ... ... ... ... ...
+> ... ... ... ... ... ... .
 >
 > Finished in 0.01938 seconds (files took 0.23698 seconds to load)
 >
 > 35 examples, 0 failures
 
-## Speicifications
-__Description:__
+***
+
+## Specifications
+### Description
 
 The application is a simulation of a toy robot moving on a square tabletop, of dimensions 5 units x 5 units.
 
 There are no other obstructions on the table surface.
 
 The robot is free to roam around the surface of the table, but must be prevented from falling to destruction. Any movement that would result in the robot falling from the table must be prevented, however further valid movement commands must still be allowed.
 
-Create an application that can read in commands of the following form - 
+Create an application that can read in commands of the following form - PLACE X,Y,F | MOVE | LEFT | RIGHT | REPORT
 
-* PLACE X,Y,F
+__PLACE__ 
 
-* MOVE
+* Will put the toy robot on the table in position X,Y and facing NORTH, SOUTH, EAST or WEST.
 
-* LEFT
+* The origin (0,0) can be considered to be the SOUTH WEST most corner.
 
-* RIGHT
+* The first valid command to the robot is a PLACE command, aXer that, any sequence of commands may be issued, in any order, including another PLACE command. The application should discard all commands in the sequence until a valid PLACE command has been executed.
 
-* REPORT
- 
-PLACE will put the toy robot on the table in position X,Y and facing NORTH, SOUTH, EAST or WEST.
+__MOVE__ 
 
-The origin (0,0) can be considered to be the SOUTH WEST most corner.
+* Will move the toy robot one unit forward in the direction it is currently facing.
 
-The first valid command to the robot is a PLACE command, aXer that, any sequence of commands may be issued, in any order, including another PLACE command. The application should discard all commands in the sequence until a valid PLACE command has been executed.
+__LEFT and RIGHT__ 
 
-MOVE will move the toy robot one unit forward in the direction it is currently facing.
+* Will rotate the robot 90 degrees in the specified direction without changing the position of the robot.
 
-LEFT and RIGHT will rotate the robot 90 degrees in the specified direction without changing the position of the robot.
+__REPORT__ 
 
-REPORT will announce the X,Y and F of the robot. This can be in any form, but standard output is sufficient.
+* Will announce the X,Y and F of the robot. This can be in any form, but standard output is sufficient.
 
-A robot that is not on the table can choose the ignore the MOVE, LEFT, RIGHT
- 
-and REPORT commands.
+* A robot that is not on the table can choose the ignore the MOVE, LEFT, RIGHT and REPORT commands.
 
-Input can be from a file, or from standard input, as the developer chooses. . Provide test data to exercise the application.
+* Input can be from a file, or from standard input, as the developer chooses. . Provide test data to exercise the application.
 
-__Constraints:__
+### Constraints
 
 The toy robot must not fall off the table during movement. This also includes the initial placement of the toy robot.
 Any move that would cause the robot to fall must be ignored.
@@ -130,8 +124,7 @@ c)
 >
 > Output: 3,3,NORTH
  
-__Deliverables:__
+### Deliverables
 
 The source files, the test data and any test code.
 It is not required to provide any graphical output showing the movement of the toy robot.
-

lib/action.rb

@@ -1,11 +1,5 @@
 # Action class
 class Action
-  attr_reader :robot
-
-  def initialize(robot)
-    @robot = robot
-  end
-
   # Place method
   # @param command [String]
   # @return Position
@@ -51,6 +45,8 @@ def right(position)
   def report(position)
     message = "Output: #{position.x},#{position.y},#{position.f} \n"
     $stdout.print message
+
+    position
   end
 
   private

lib/handle_input.rb

@@ -6,10 +6,7 @@ class HandleInput
 
   # Command Options
   PLACE   = /^PLACE\s+\d+\s*,\s*\d+\s*,\s*(WEST||NORTH||EAST||SOUTH)$/
-  MOVE    = /^MOVE$/
-  LEFT    = /^LEFT$/
-  RIGHT   = /^RIGHT$/
-  REPORT  = /^REPORT$/
+  ACTIONS = %w[MOVE LEFT RIGHT REPORT].freeze
 
   def initialize(robot, table, action)
     @robot = robot
@@ -21,17 +18,23 @@ def initialize(robot, table, action)
   # @param command [String]
   # @return Position
   def interpret(command)
-    return exec(action.place(command)) if PLACE.match?(command)
+    return unless command.match(PLACE) || ACTIONS.include?(command)
 
+    return exec(action.place(command)) if command.match?(PLACE)
     return if robot.not_in_place?
 
-    return exec(action.move(robot.position)) if MOVE.match?(command)
-
-    return exec(action.left(robot.position)) if LEFT.match?(command)
+    exec(next_position(robot.position, command))
+  end
 
-    return exec(action.right(robot.position)) if RIGHT.match?(command)
+  private
 
-    return action.report(robot.position) if REPORT.match?(command)
+  # Next position method
+  # Find the robot's next position if an action was to be performed
+  # @param position [Object]
+  # @param command [String]
+  # @return Position
+  def next_position(position, command)
+    action.public_send ACTIONS.detect { |e| e == command }.downcase, position
   end
 
   # Exec method

spec/action_spec.rb

@@ -3,17 +3,9 @@
 require './lib/action'
 
 describe Action do
-  describe '#initialize' do
-    it 'should have a current_position attribute which is nil' do
-      instance = Action.new(@robot)
-
-      expect(instance.robot).to be_nil
-    end
-  end
-
   describe '#place' do
     it 'should return an instance of Position' do
-      instance = Action.new(@robot)
+      instance = Action.new
       command = 'PLACE 0,0,NORTH'
 
       expect(instance.place(command)).to be_a Position
@@ -22,7 +14,7 @@
 
   describe '#move' do
     it 'should return an instance of Position' do
-      instance = Action.new(@robot)
+      instance = Action.new
       position = Position.new(0, 0, 'NORTH')
 
       expect(instance.move(position)).to be_a Position
@@ -31,7 +23,7 @@
 
   describe '#left' do
     it 'should return an instance of Position' do
-      instance = Action.new(@robot)
+      instance = Action.new
       position = Position.new(0, 0, 'NORTH')
 
       expect(instance.left(position)).to be_a Position
@@ -40,47 +32,47 @@
 
   describe '#right' do
     it 'should return an instance of Position' do
-      instance = Action.new(@robot)
+      instance = Action.new
       position = Position.new(0, 0, 'NORTH')
 
       expect(instance.right(position)).to be_a Position
     end
   end
 
   describe '#report' do
-    it 'should return nil' do
-      instance = Action.new(@robot)
+    it 'should return an instance of Position' do
+      instance = Action.new
       position = Position.new(0, 0, 'NORTH')
 
-      expect(instance.report(position)).to be_nil
+      expect(instance.right(position)).to be_a Position
     end
   end
 
   describe '#prev_option' do
     it 'should return the previous value in the OPTIONS array' do
-      instance = Action.new(@robot)
+      instance = Action.new
 
       expect(instance.send(:prev_option, 'NORTH')).to be_a String
       expect(instance.send(:prev_option, 'NORTH')).to eq 'WEST'
     end
 
     it 'should return nil if the direction param is empty' do
-      instance = Action.new(@robot)
+      instance = Action.new
 
       expect(instance.send(:prev_option, '')).to be_nil
     end
   end
 
   describe '#next_option' do
     it 'should return the next value in the OPTIONS array' do
-      instance = Action.new(@robot)
+      instance = Action.new
 
       expect(instance.send(:next_option, 'NORTH')).to be_a String
       expect(instance.send(:next_option, 'NORTH')).to eq 'EAST'
     end
 
     it 'should return nil if the direction param is empty' do
-      instance = Action.new(@robot)
+      instance = Action.new
 
       expect(instance.send(:next_option, '')).to be_nil
     end

spec/handle_input_spec.rb

@@ -18,25 +18,22 @@
   end
 
   describe '#interpret' do
-    it 'should return an instance of Position command matches PLACE pattern' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return an instance of Position when command matches PLACE pattern' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command = 'PLACE 1,2,NORTH'
 
       expect(instance.interpret(command)).to be_a Position
     end
 
-    it 'should return nil if robot is not in place' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return nil when robot is not in place' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command = ''
 
       expect(instance.interpret(command)).to be_nil
     end
 
-    it 'should return an instance of Position if command matches MOVE pattern' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return an instance of Position when command matches MOVE pattern' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command1 = 'PLACE 1,2,NORTH'
       command2 = 'MOVE'
 
@@ -45,9 +42,8 @@
       expect(instance.interpret(command2)).to be_a Position
     end
 
-    it 'should return an instance of Position if command matches LEFT pattern' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return an instance of Position when command matches LEFT pattern' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command1 = 'PLACE 1,2,NORTH'
       command2 = 'LEFT'
 
@@ -56,9 +52,8 @@
       expect(instance.interpret(command2)).to be_a Position
     end
 
-    it 'should return an instance of Position if command matches RIGHT pattern' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return an instance of Position when command matches RIGHT pattern' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command1 = 'PLACE 1,2,NORTH'
       command2 = 'RIGHT'
 
@@ -67,33 +62,40 @@
       expect(instance.interpret(command2)).to be_a Position
     end
 
-    it 'should return nil if command matches REPORT pattern' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+    it 'should return an instance of Position when command matches REPORT pattern' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       command1 = 'PLACE 1,2,NORTH'
       command2 = 'REPORT'
 
       instance.interpret(command1)
 
-      expect(instance.interpret(command2)).to be_nil
+      expect(instance.interpret(command2)).to be_a Position
+    end
+  end
+
+  describe '#next_position' do
+    it 'should return an instance of Position' do
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
+      position = Position.new(0, 0, 'NORTH')
+      command = 'MOVE'
+
+      expect(instance.send(:next_position, position, command)).to be_a Position
     end
   end
 
   describe '#exec' do
     it 'should return an instance of Position if position is a valid table position' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       position = Position.new(0, 0, 'NORTH')
 
-      expect(instance.exec(position)).to be_a Position
+      expect(instance.send(:exec, position)).to be_a Position
     end
 
     it 'should return nil if position is not a valid table position' do
-      robot = Robot.new
-      instance = HandleInput.new(robot, Table.new, Action.new(robot))
+      instance = HandleInput.new(Robot.new, Table.new, Action.new)
       position = Position.new(0, 6, 'NORTH')
 
-      expect(instance.exec(position)).to be_nil
+      expect(instance.send(:exec, position)).to be_nil
     end
   end
 end