exercises(robot-simulator): implement

config.json

@@ -979,6 +979,14 @@
           "events",
           "reactive_programming"
         ]
+      },
+      {
+        "slug": "robot-simulator",
+        "name": "Robot Simulator",
+        "uuid": "cfedbb93-eda4-49f9-92a1-aa1a6cc8453f",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },

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 +1,21 @@
+{
+  "authors": [
+    "ilmanzo"
+  ],
+  "contributors": [
+    "ee7"
+  ],
+  "files": {
+    "solution": [
+      "robot_simulator.nim"
+    ],
+    "test": [
+      "test_robot_simulator.nim"
+    ],
+    "example": [
+      ".meta/example.nim"
+    ]
+  },
+  "blurb": "Write a robot simulator.",
+  "source": "Inspired by an interview question at a famous company."
+}

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

@@ -0,0 +1,29 @@
+type
+  Compass* = enum
+    North, East, South, West
+
+  Robot* = object
+    direction*: Compass
+    x*: int
+    y*: int
+
+func initRobot*(facing = North, x = 0, y = 0): Robot =
+  Robot(direction: facing, x: x, y: y)
+
+func move*(robot: var Robot, instructions: string) =
+  for c in instructions:
+    case c
+    of 'L':
+      robot.direction =
+          if robot.direction == Compass.low: Compass.high else: pred(robot.direction)
+    of 'R':
+      robot.direction =
+          if robot.direction == Compass.high: Compass.low else: succ(robot.direction)
+    of 'A':
+      case robot.direction:
+        of North: inc robot.y
+        of South: dec robot.y
+        of East: inc robot.x
+        of West: dec robot.x
+    else:
+      discard

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.nim

@@ -0,0 +1,14 @@
+type
+  Compass* = enum
+    North, East, South, West
+
+  Robot* = object
+    direction*: Compass
+    x*: int
+    y*: int
+
+proc initRobot*(facing = North, x = 0, y = 0): Robot =
+  discard
+
+proc move*(robot: var Robot, instructions: string) =
+  discard

exercises/practice/robot-simulator/test_robot_simulator.nim

@@ -0,0 +1,125 @@
+import unittest
+import robot_simulator
+
+suite "Robot Simulator":
+  test "create robot: at origin facing north":
+    var robot = initRobot()
+    check robot.direction == North
+
+  test "create robot: at negative position facing south":
+    var robot = initRobot(South, -1, -1)
+    check robot.direction == South
+    check robot.x == -1
+    check robot.y == -1
+
+  test "rotating clockwise: changes north to east":
+    var robot = initRobot()
+    robot.move("R")
+    check robot.direction == East
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating clockwise: changes east to south":
+    var robot = initRobot(East)
+    robot.move("R")
+    check robot.direction == South
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating clockwise: changes south to west":
+    var robot = initRobot(South)
+    robot.move("R")
+    check robot.direction == West
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating clockwise: changes west to north":
+    var robot = initRobot(West)
+    robot.move("R")
+    check robot.direction == North
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating counter-clockwise: changes north to west":
+    var robot = initRobot()
+    robot.move("L")
+    check robot.direction == West
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating counter-clockwise: changes west to south":
+    var robot = initRobot(West)
+    robot.move("L")
+    check robot.direction == South
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating counter-clockwise: changes south to east":
+    var robot = initRobot(South)
+    robot.move("L")
+    check robot.direction == East
+    check robot.x == 0
+    check robot.y == 0
+
+  test "rotating counter-clockwise: changes east to north":
+    var robot = initRobot(East)
+    robot.move("L")
+    check robot.direction == North
+    check robot.x == 0
+    check robot.y == 0
+
+  test "moving forward one: facing north increments Y":
+    var robot = initRobot()
+    robot.move("A")
+    check robot.direction == North
+    check robot.x == 0
+    check robot.y == 1
+
+  test "moving forward one: facing south decrements Y":
+    var robot = initRobot(South)
+    robot.move("A")
+    check robot.direction == South
+    check robot.x == 0
+    check robot.y == -1
+
+  test "moving forward one: facing east increments X":
+    var robot = initRobot(East)
+    robot.move("A")
+    check robot.direction == East
+    check robot.x == 1
+    check robot.y == 0
+
+  test "moving forward one: facing west decrements X":
+    var robot = initRobot(West)
+    robot.move("A")
+    check robot.direction == West
+    check robot.x == -1
+    check robot.y == 0
+
+  test "Follow series of instructions: moving east and north from README":
+    var robot = initRobot(North, 7, 3)
+    robot.move("RAALAL")
+    check robot.direction == West
+    check robot.x == 9
+    check robot.y == 4
+
+  test "Follow series of instructions: moving west and north":
+    var robot = initRobot()
+    robot.move("LAAARALA")
+    check robot.direction == West
+    check robot.x == -4
+    check robot.y == 1
+
+  test "Follow series of instructions: moving west and south":
+    var robot = initRobot(East, 2, -7)
+    robot.move("RRAAAAALA")
+    check robot.direction == South
+    check robot.x == -3
+    check robot.y == -8
+
+  test "Follow series of instructions: moving east and north":
+    var robot = initRobot(South, 8, 4)
+    robot.move("LAAARRRALLLL")
+    check robot.direction == North
+    check robot.x == 11
+    check robot.y == 5