robot-simulator (#49)

Author: glennj

config.json

@@ -374,6 +374,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 4
+      },
+      {
+        "slug": "robot-simulator",
+        "name": "Robot Simulator",
+        "uuid": "55452cf4-0037-4bf5-a518-c16fb5d1da83",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
       }
     ]
   },

exercises/practice/robot-simulator/.busted

@@ -0,0 +1,5 @@
+return {
+  default = {
+    ROOT = { '.' }
+  }
+}

exercises/practice/robot-simulator/.docs/instructions.md

@@ -0,0 +1,25 @@
+# Instructions
+
+Write a robot simulator.
+
+A robot factory's test facility needs a program to verify robot movements.
+
+The robots have three possible movements:
+
+- turn right
+- turn left
+- advance
+
+Robots are placed on a hypothetical infinite grid, facing a particular direction (north, east, south, or west) at a set of {x,y} coordinates,
+e.g., {3,8}, with coordinates increasing to the north and east.
+
+The robot then receives a number of instructions, at which point the testing facility verifies the robot's new position, and in which direction it is pointing.
+
+- The letter-string "RAALAL" means:
+  - Turn right
+  - Advance twice
+  - Turn left
+  - Advance once
+  - Turn left yet again
+- Say a robot starts at {7, 3} facing north.
+  Then running this stream of instructions should leave it at {9, 4} facing west.

exercises/practice/robot-simulator/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "robot_simulator.moon"
+    ],
+    "test": [
+      "robot_simulator_spec.moon"
+    ],
+    "example": [
+      ".meta/example.moon"
+    ]
+  },
+  "blurb": "Write a robot simulator.",
+  "source": "Inspired by an interview question at a famous company."
+}

exercises/practice/robot-simulator/.meta/example.moon

@@ -0,0 +1,29 @@
+Turns = {
+  north: {left: 'west',  right: 'east'},
+  east:  {left: 'north', right: 'south'},
+  south: {left: 'east',  right: 'west'},
+  west:  {left: 'south', right: 'north'},
+}
+
+
+class Robot
+  new: (params) =>
+    @_x = params.x
+    @_y = params.y
+    @_dir = params.direction
+
+  x: => @_x
+  y: => @_y
+  direction: => @_dir
+
+  move: (instructions) =>
+    for instruction in instructions\gmatch('[RLA]')
+      switch instruction
+        when 'R' then @_dir = Turns[@_dir].right
+        when 'L' then @_dir = Turns[@_dir].left
+        when 'A'
+          switch @_dir
+            when 'north' then @_y += 1
+            when 'east'  then @_x += 1
+            when 'south' then @_y -= 1
+            when 'west'  then @_x -= 1

exercises/practice/robot-simulator/.meta/spec_generator.moon

@@ -0,0 +1,26 @@
+{
+  module_name: 'Robot',
+
+  generate_test: (case, level) ->
+    local lines
+    switch case.property
+      when 'create'
+        lines = {
+          "robot = Robot x: #{case.input.position.x}, y: #{case.input.position.y}, direction: #{quote case.input.direction}",
+          "assert.are.equal #{case.expected.position.x}, robot\\x!",
+          "assert.are.equal #{case.expected.position.y}, robot\\y!",
+          "assert.are.equal #{quote case.expected.direction}, robot\\direction!"
+        }
+
+      when 'move'
+        lines = {
+          "robot = Robot x: #{case.input.position.x}, y: #{case.input.position.y}, direction: #{quote case.input.direction}",
+          "robot\\move #{quote case.input.instructions}",
+
+          "assert.are.equal #{case.expected.position.x}, robot\\x!",
+          "assert.are.equal #{case.expected.position.y}, robot\\y!",
+          "assert.are.equal #{quote case.expected.direction}, robot\\direction!"
+        }
+
+    table.concat [indent line, level for line in *lines], '\n'
+}

exercises/practice/robot-simulator/.meta/tests.toml

@@ -0,0 +1,64 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[c557c16d-26c1-4e06-827c-f6602cd0785c]
+description = "Create robot -> at origin facing north"
+
+[bf0dffce-f11c-4cdb-8a5e-2c89d8a5a67d]
+description = "Create robot -> at negative position facing south"
+
+[8cbd0086-6392-4680-b9b9-73cf491e67e5]
+description = "Rotating clockwise -> changes north to east"
+
+[8abc87fc-eab2-4276-93b7-9c009e866ba1]
+description = "Rotating clockwise -> changes east to south"
+
+[3cfe1b85-bbf2-4bae-b54d-d73e7e93617a]
+description = "Rotating clockwise -> changes south to west"
+
+[5ea9fb99-3f2c-47bd-86f7-46b7d8c3c716]
+description = "Rotating clockwise -> changes west to north"
+
+[fa0c40f5-6ba3-443d-a4b3-58cbd6cb8d63]
+description = "Rotating counter-clockwise -> changes north to west"
+
+[da33d734-831f-445c-9907-d66d7d2a92e2]
+description = "Rotating counter-clockwise -> changes west to south"
+
+[bd1ca4b9-4548-45f4-b32e-900fc7c19389]
+description = "Rotating counter-clockwise -> changes south to east"
+
+[2de27b67-a25c-4b59-9883-bc03b1b55bba]
+description = "Rotating counter-clockwise -> changes east to north"
+
+[f0dc2388-cddc-4f83-9bed-bcf46b8fc7b8]
+description = "Moving forward one -> facing north increments Y"
+
+[2786cf80-5bbf-44b0-9503-a89a9c5789da]
+description = "Moving forward one -> facing south decrements Y"
+
+[84bf3c8c-241f-434d-883d-69817dbd6a48]
+description = "Moving forward one -> facing east increments X"
+
+[bb69c4a7-3bbf-4f64-b415-666fa72d7b04]
+description = "Moving forward one -> facing west decrements X"
+
+[e34ac672-4ed4-4be3-a0b8-d9af259cbaa1]
+description = "Follow series of instructions -> moving east and north from README"
+
+[f30e4955-4b47-4aa3-8b39-ae98cfbd515b]
+description = "Follow series of instructions -> moving west and north"
+
+[3e466bf6-20ab-4d79-8b51-264165182fca]
+description = "Follow series of instructions -> moving west and south"
+
+[41f0bb96-c617-4e6b-acff-a4b279d44514]
+description = "Follow series of instructions -> moving east and north"

exercises/practice/robot-simulator/robot_simulator.moon

@@ -0,0 +1,15 @@
+class Robot
+  new: (params) =>
+    error 'Implement the constructor'
+
+  x: =>
+    error 'Implement the x method'
+
+  y: =>
+    error 'Implement the y method'
+
+  direction: =>
+    error 'Implement the direction method'
+
+  move: (instructions) =>
+    error 'Implement the move method'

exercises/practice/robot-simulator/robot_simulator_spec.moon

@@ -0,0 +1,131 @@
+Robot = require 'robot_simulator'
+
+describe 'robot-simulator', ->
+  describe 'Create robot', ->
+    it 'at origin facing north', ->
+      robot = Robot x: 0, y: 0, direction: 'north'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'north', robot\direction!
+
+    pending 'at negative position facing south', ->
+      robot = Robot x: -1, y: -1, direction: 'south'
+      assert.are.equal -1, robot\x!
+      assert.are.equal -1, robot\y!
+      assert.are.equal 'south', robot\direction!
+
+  describe 'Rotating clockwise', ->
+    pending 'changes north to east', ->
+      robot = Robot x: 0, y: 0, direction: 'north'
+      robot\move 'R'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'east', robot\direction!
+
+    pending 'changes east to south', ->
+      robot = Robot x: 0, y: 0, direction: 'east'
+      robot\move 'R'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'south', robot\direction!
+
+    pending 'changes south to west', ->
+      robot = Robot x: 0, y: 0, direction: 'south'
+      robot\move 'R'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'west', robot\direction!
+
+    pending 'changes west to north', ->
+      robot = Robot x: 0, y: 0, direction: 'west'
+      robot\move 'R'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'north', robot\direction!
+
+  describe 'Rotating counter-clockwise', ->
+    pending 'changes north to west', ->
+      robot = Robot x: 0, y: 0, direction: 'north'
+      robot\move 'L'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'west', robot\direction!
+
+    pending 'changes west to south', ->
+      robot = Robot x: 0, y: 0, direction: 'west'
+      robot\move 'L'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'south', robot\direction!
+
+    pending 'changes south to east', ->
+      robot = Robot x: 0, y: 0, direction: 'south'
+      robot\move 'L'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'east', robot\direction!
+
+    pending 'changes east to north', ->
+      robot = Robot x: 0, y: 0, direction: 'east'
+      robot\move 'L'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'north', robot\direction!
+
+  describe 'Moving forward one', ->
+    pending 'facing north increments Y', ->
+      robot = Robot x: 0, y: 0, direction: 'north'
+      robot\move 'A'
+      assert.are.equal 0, robot\x!
+      assert.are.equal 1, robot\y!
+      assert.are.equal 'north', robot\direction!
+
+    pending 'facing south decrements Y', ->
+      robot = Robot x: 0, y: 0, direction: 'south'
+      robot\move 'A'
+      assert.are.equal 0, robot\x!
+      assert.are.equal -1, robot\y!
+      assert.are.equal 'south', robot\direction!
+
+    pending 'facing east increments X', ->
+      robot = Robot x: 0, y: 0, direction: 'east'
+      robot\move 'A'
+      assert.are.equal 1, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'east', robot\direction!
+
+    pending 'facing west decrements X', ->
+      robot = Robot x: 0, y: 0, direction: 'west'
+      robot\move 'A'
+      assert.are.equal -1, robot\x!
+      assert.are.equal 0, robot\y!
+      assert.are.equal 'west', robot\direction!
+
+  describe 'Follow series of instructions', ->
+    pending 'moving east and north from README', ->
+      robot = Robot x: 7, y: 3, direction: 'north'
+      robot\move 'RAALAL'
+      assert.are.equal 9, robot\x!
+      assert.are.equal 4, robot\y!
+      assert.are.equal 'west', robot\direction!
+
+    pending 'moving west and north', ->
+      robot = Robot x: 0, y: 0, direction: 'north'
+      robot\move 'LAAARALA'
+      assert.are.equal -4, robot\x!
+      assert.are.equal 1, robot\y!
+      assert.are.equal 'west', robot\direction!
+
+    pending 'moving west and south', ->
+      robot = Robot x: 2, y: -7, direction: 'east'
+      robot\move 'RRAAAAALA'
+      assert.are.equal -3, robot\x!
+      assert.are.equal -8, robot\y!
+      assert.are.equal 'south', robot\direction!
+
+    pending 'moving east and north', ->
+      robot = Robot x: 8, y: 4, direction: 'south'
+      robot\move 'LAAARRRALLLL'
+      assert.are.equal 11, robot\x!
+      assert.are.equal 5, robot\y!
+      assert.are.equal 'north', robot\direction!