Add series (#111)

Author: glennj

config.json

@@ -498,6 +498,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "series",
+        "name": "Series",
+        "uuid": "9206db65-e0c9-4ea5-afc2-23910ea6dca2",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "sieve",
         "name": "Sieve",

exercises/practice/series/.busted

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

exercises/practice/series/.docs/instructions.append.md

@@ -0,0 +1,12 @@
+# dummy
+
+## MoonScript-specific Instructions
+
+This exercise requires you to implement the `slices` function as an **iterator**.
+Iterators are described in the manual in "The generic for loop" under the [For Statement][lua-for] section.
+
+There is a thorough tutorial at [Lua Iterators][tutorialspoint].
+
+
+[lua-for]: https://www.lua.org/manual/5.4/manual.html#3.3.5
+[tutorialspoint]: https://www.tutorialspoint.com/lua/lua_iterators.htm

exercises/practice/series/.docs/instructions.md

@@ -0,0 +1,19 @@
+# Instructions
+
+Given a string of digits, output all the contiguous substrings of length `n` in that string in the order that they appear.
+
+For example, the string "49142" has the following 3-digit series:
+
+- "491"
+- "914"
+- "142"
+
+And the following 4-digit series:
+
+- "4914"
+- "9142"
+
+And if you ask for a 6-digit series from a 5-digit string, you deserve whatever you get.
+
+Note that these series are only required to occupy _adjacent positions_ in the input;
+the digits need not be _numerically consecutive_.

exercises/practice/series/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "series.moon"
+    ],
+    "test": [
+      "series_spec.moon"
+    ],
+    "example": [
+      ".meta/example.moon"
+    ]
+  },
+  "blurb": "Given a string of digits, output all the contiguous substrings of length `n` in that string.",
+  "source": "A subset of the Problem 8 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=8"
+}

exercises/practice/series/.meta/example.moon

@@ -0,0 +1,15 @@
+{
+  slices: (series, length) ->
+    assert length > -1, 'slice length cannot be negative'
+    assert length > 0, 'slice length cannot be zero'
+    assert #series > 0, 'series cannot be empty'
+    assert #series >= length, 'slice length cannot be greater than series length'
+
+    -- a "stateful iterator"
+    idx = 0
+    last = #series - length
+    ->
+      if idx <= last
+        idx += 1
+        return series\sub(idx, idx + length - 1)
+}

exercises/practice/series/.meta/spec_generator.moon

@@ -0,0 +1,23 @@
+list_of_words = (list) ->
+  "{#{table.concat [quote word for word in *list], ', '}}"
+
+{
+  module_imports: {'slices'},
+
+  generate_test: (case, level) ->
+    cmd = "slices #{quote case.input.series}, #{case.input.sliceLength}"
+
+    local lines
+    if case.expected.error
+      lines = {
+        "f = -> #{cmd}"
+        "assert.has_error f, #{quote case.expected.error}"
+      }
+    else
+      lines = {
+        "result = [s for s in #{cmd}]"
+        "expected = #{list_of_words case.expected}"
+        "assert.are.same expected, result"
+      }
+    table.concat [indent line, level for line in *lines], '\n'
+}

exercises/practice/series/.meta/tests.toml

@@ -0,0 +1,43 @@
+# 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.
+
+[7ae7a46a-d992-4c2a-9c15-a112d125ebad]
+description = "slices of one from one"
+
+[3143b71d-f6a5-4221-aeae-619f906244d2]
+description = "slices of one from two"
+
+[dbb68ff5-76c5-4ccd-895a-93dbec6d5805]
+description = "slices of two"
+
+[19bbea47-c987-4e11-a7d1-e103442adf86]
+description = "slices of two overlap"
+
+[8e17148d-ba0a-4007-a07f-d7f87015d84c]
+description = "slices can include duplicates"
+
+[bd5b085e-f612-4f81-97a8-6314258278b0]
+description = "slices of a long series"
+
+[6d235d85-46cf-4fae-9955-14b6efef27cd]
+description = "slice length is too large"
+
+[d7957455-346d-4e47-8e4b-87ed1564c6d7]
+description = "slice length is way too large"
+
+[d34004ad-8765-4c09-8ba1-ada8ce776806]
+description = "slice length cannot be zero"
+
+[10ab822d-8410-470a-a85d-23fbeb549e54]
+description = "slice length cannot be negative"
+
+[c7ed0812-0e4b-4bf3-99c4-28cbbfc246a2]
+description = "empty series is invalid"

exercises/practice/series/series.moon

@@ -0,0 +1,4 @@
+{
+  slices: (series, length) ->
+    error 'Implement me'
+}

exercises/practice/series/series_spec.moon

@@ -0,0 +1,52 @@
+import slices from require 'series'
+
+describe 'series', ->
+  it 'slices of one from one', ->
+    result = [s for s in slices '1', 1]
+    expected = {'1'}
+    assert.are.same expected, result
+
+  pending 'slices of one from two', ->
+    result = [s for s in slices '12', 1]
+    expected = {'1', '2'}
+    assert.are.same expected, result
+
+  pending 'slices of two', ->
+    result = [s for s in slices '35', 2]
+    expected = {'35'}
+    assert.are.same expected, result
+
+  pending 'slices of two overlap', ->
+    result = [s for s in slices '9142', 2]
+    expected = {'91', '14', '42'}
+    assert.are.same expected, result
+
+  pending 'slices can include duplicates', ->
+    result = [s for s in slices '777777', 3]
+    expected = {'777', '777', '777', '777'}
+    assert.are.same expected, result
+
+  pending 'slices of a long series', ->
+    result = [s for s in slices '918493904243', 5]
+    expected = {'91849', '18493', '84939', '49390', '93904', '39042', '90424', '04243'}
+    assert.are.same expected, result
+
+  pending 'slice length is too large', ->
+    f = -> slices '12345', 6
+    assert.has_error f, 'slice length cannot be greater than series length'
+
+  pending 'slice length is way too large', ->
+    f = -> slices '12345', 42
+    assert.has_error f, 'slice length cannot be greater than series length'
+
+  pending 'slice length cannot be zero', ->
+    f = -> slices '12345', 0
+    assert.has_error f, 'slice length cannot be zero'
+
+  pending 'slice length cannot be negative', ->
+    f = -> slices '123', -1
+    assert.has_error f, 'slice length cannot be negative'
+
+  pending 'empty series is invalid', ->
+    f = -> slices '', 1
+    assert.has_error f, 'series cannot be empty'