Add split-second-stopwatch

Author: ryanplusplus

config.json

@@ -1489,6 +1489,19 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 3
+      },
+      {
+        "slug": "split-second-stopwatch",
+        "name": "Split-Second Stopwatch",
+        "uuid": "49a0daf5-ecf8-41ad-8517-f969b770bf32",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3,
+        "topics": [
+          "strings",
+          "text-formatting",
+          "time"
+        ]
       }
     ]
   },

exercises/practice/split-second-stopwatch/.busted

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

exercises/practice/split-second-stopwatch/.docs/instructions.md

@@ -0,0 +1,22 @@
+# Instructions
+
+Your task is to build a stopwatch to keep precise track of lap times.
+
+The stopwatch uses four commands (start, stop, lap, and reset) to keep track of:
+
+1. The current lap's tracked time
+2. Previously recorded lap times
+
+What commands can be used depends on which state the stopwatch is in:
+
+1. Ready: initial state
+2. Running: tracking time
+3. Stopped: not tracking time
+
+| Command | Begin state | End state | Effect                                                   |
+| ------- | ----------- | --------- | -------------------------------------------------------- |
+| Start   | Ready       | Running   | Start tracking time                                      |
+| Start   | Stopped     | Running   | Resume tracking time                                     |
+| Stop    | Running     | Stopped   | Stop tracking time                                       |
+| Lap     | Running     | Running   | Add current lap to previous laps, then reset current lap |
+| Reset   | Stopped     | Ready     | Reset current lap and clear previous laps                |

exercises/practice/split-second-stopwatch/.docs/introduction.md

@@ -0,0 +1,6 @@
+# Introduction
+
+You've always run for the thrill of it — no schedules, no timers, just the sound of your feet on the pavement.
+But now that you've joined a competitive running crew, things are getting serious.
+Training sessions are timed to the second, and every split second counts.
+To keep pace, you've picked up the _Split-Second Stopwatch_ — a sleek, high-tech gadget that's about to become your new best friend.

exercises/practice/split-second-stopwatch/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "ryanplusplus"
+  ],
+  "files": {
+    "solution": [
+      "split-second-stopwatch.lua"
+    ],
+    "test": [
+      "split-second-stopwatch_spec.lua"
+    ],
+    "example": [
+      ".meta/example.lua"
+    ]
+  },
+  "blurb": "Keep track of time through a digital stopwatch.",
+  "source": "Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2547"
+}

exercises/practice/split-second-stopwatch/.meta/example.lua

@@ -0,0 +1,71 @@
+local function time_from_seconds(seconds)
+  local hours = math.floor(seconds / 3600)
+  local minutes = math.floor((seconds % 3600) / 60)
+  local secs = seconds % 60
+  return string.format('%02d:%02d:%02d', hours, minutes, secs)
+end
+
+local function seconds_from_time(timestamp)
+  local hours, minutes, seconds = timestamp:match("(%d+):(%d+):(%d+)")
+  return tonumber(hours) * 3600 + tonumber(minutes) * 60 + tonumber(seconds)
+end
+
+local Stopwatch = {}
+
+function Stopwatch:new()
+  local obj = { _state = 'stopped' }
+  setmetatable(obj, self)
+  self.__index = self
+  obj:reset()
+  return obj
+end
+
+function Stopwatch:start()
+  assert(self._state ~= 'running', 'cannot start an already running stopwatch')
+  self._state = 'running'
+end
+
+function Stopwatch:stop()
+  assert(self._state == 'running', 'cannot stop a stopwatch that is not running')
+  self._state = 'stopped'
+end
+
+function Stopwatch:reset()
+  assert(self._state == 'stopped', 'cannot reset a stopwatch that is not stopped')
+  self._state = 'ready'
+  self._total_time = 0
+  self._lap_time = 0
+  self._previous_laps = {}
+end
+
+function Stopwatch:advance_time(timestamp)
+  if self._state == 'running' then
+    local time_in_seconds = seconds_from_time(timestamp)
+    self._total_time = self._total_time + time_in_seconds
+    self._lap_time = self._lap_time + time_in_seconds
+  end
+end
+
+function Stopwatch:total()
+  return time_from_seconds(self._total_time)
+end
+
+function Stopwatch:lap()
+  assert(self._state == 'running', 'cannot lap a stopwatch that is not running')
+  table.insert(self._previous_laps, time_from_seconds(self._lap_time))
+  self._lap_time = 0
+end
+
+function Stopwatch:current_lap()
+  return time_from_seconds(self._lap_time)
+end
+
+function Stopwatch:previous_laps()
+  return self._previous_laps
+end
+
+function Stopwatch:state()
+  return self._state
+end
+
+return Stopwatch

exercises/practice/split-second-stopwatch/.meta/spec_generator.lua

@@ -0,0 +1,37 @@
+local utils = require 'utils'
+
+local function render_expected(expected)
+  if type(expected) == 'table' then
+    return '{ ' .. table.concat(utils.map(expected, utils.stringify), ', ') .. '}'
+  else
+    return utils.stringify(expected)
+  end
+end
+
+return {
+  module_name = 'Stopwatch',
+
+  generate_test = function(case)
+    local lines = {}
+
+    for _, command in ipairs(case.input.commands) do
+      if command.command == 'new' then
+        table.insert(lines, 'local stopwatch = Stopwatch:new()')
+      elseif command.expected and command.expected.error then
+        table.insert(lines,
+                     ('assert.has_error(function() stopwatch:%s() end, %s)'):format(utils.snake_case(command.command),
+                                                                                    utils.stringify(
+                                                                                      command.expected.error)))
+      elseif command.by then
+        table.insert(lines, ('stopwatch:%s(%s)'):format(utils.snake_case(command.command), render_expected(command.by)))
+      elseif command.expected then
+        table.insert(lines, ('assert.are.same(%s, stopwatch:%s())'):format(render_expected(command.expected),
+                                                                           utils.snake_case(command.command)))
+      else
+        table.insert(lines, ('stopwatch:%s()'):format(utils.snake_case(command.command)))
+      end
+    end
+
+    return table.concat(lines, '\n')
+  end
+}

exercises/practice/split-second-stopwatch/.meta/tests.toml

@@ -0,0 +1,97 @@
+# 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.
+
+[ddb238ea-99d4-4eaa-a81d-3c917a525a23]
+description = "new stopwatch starts in ready state"
+
+[b19635d4-08ad-4ac3-b87f-aca10e844071]
+description = "new stopwatch's current lap has no elapsed time"
+
+[492eb532-268d-43ea-8a19-2a032067d335]
+description = "new stopwatch's total has no elapsed time"
+
+[8a892c1e-9ef7-4690-894e-e155a1fe4484]
+description = "new stopwatch does not have previous laps"
+
+[5b2705b6-a584-4042-ba3a-4ab8d0ab0281]
+description = "start from ready state changes state to running"
+
+[748235ce-1109-440b-9898-0a431ea179b6]
+description = "start does not change previous laps"
+
+[491487b1-593d-423e-a075-aa78d449ff1f]
+description = "start initiates time tracking for current lap"
+
+[a0a7ba2c-8db6-412c-b1b6-cb890e9b72ed]
+description = "start initiates time tracking for total"
+
+[7f558a17-ef6d-4a5b-803a-f313af7c41d3]
+description = "start cannot be called from running state"
+
+[32466eef-b2be-4d60-a927-e24fce52dab9]
+description = "stop from running state changes state to stopped"
+
+[621eac4c-8f43-4d99-919c-4cad776d93df]
+description = "stop pauses time tracking for current lap"
+
+[465bcc82-7643-41f2-97ff-5e817cef8db4]
+description = "stop pauses time tracking for total"
+
+[b1ba7454-d627-41ee-a078-891b2ed266fc]
+description = "stop cannot be called from ready state"
+
+[5c041078-0898-44dc-9d5b-8ebb5352626c]
+description = "stop cannot be called from stopped state"
+
+[3f32171d-8fbf-46b6-bc2b-0810e1ec53b7]
+description = "start from stopped state changes state to running"
+
+[626997cb-78d5-4fe8-b501-29fdef804799]
+description = "start from stopped state resumes time tracking for current lap"
+
+[58487c53-ab26-471c-a171-807ef6363319]
+description = "start from stopped state resumes time tracking for total"
+
+[091966e3-ed25-4397-908b-8bb0330118f8]
+description = "lap adds current lap to previous laps"
+
+[1aa4c5ee-a7d5-4d59-9679-419deef3c88f]
+description = "lap resets current lap and resumes time tracking"
+
+[4b46b92e-1b3f-46f6-97d2-0082caf56e80]
+description = "lap continues time tracking for total"
+
+[ea75d36e-63eb-4f34-97ce-8c70e620bdba]
+description = "lap cannot be called from ready state"
+
+[63731154-a23a-412d-a13f-c562f208eb1e]
+description = "lap cannot be called from stopped state"
+
+[e585ee15-3b3f-4785-976b-dd96e7cc978b]
+description = "stop does not change previous laps"
+
+[fc3645e2-86cf-4d11-97c6-489f031103f6]
+description = "reset from stopped state changes state to ready"
+
+[20fbfbf7-68ad-4310-975a-f5f132886c4e]
+description = "reset resets current lap"
+
+[00a8f7bb-dd5c-43e5-8705-3ef124007662]
+description = "reset clears previous laps"
+
+[76cea936-6214-4e95-b6d1-4d4edcf90499]
+description = "reset cannot be called from ready state"
+
+[ba4d8e69-f200-4721-b59e-90d8cf615153]
+description = "reset cannot be called from running state"
+
+[0b01751a-cb57-493f-bb86-409de6e84306]
+description = "supports very long laps"

exercises/practice/split-second-stopwatch/split-second-stopwatch.lua

@@ -0,0 +1,37 @@
+local Stopwatch = {}
+
+function Stopwatch:new()
+  local obj = {}
+  setmetatable(obj, self)
+  self.__index = self
+  return obj
+end
+
+function Stopwatch:start()
+end
+
+function Stopwatch:stop()
+end
+
+function Stopwatch:reset()
+end
+
+function Stopwatch:advance_time(timestamp)
+end
+
+function Stopwatch:total()
+end
+
+function Stopwatch:lap()
+end
+
+function Stopwatch:current_lap()
+end
+
+function Stopwatch:previous_laps()
+end
+
+function Stopwatch:state()
+end
+
+return Stopwatch