Update list-ops tests (#588)

Author: ryanplusplus

exercises/practice/list-ops/.meta/example.lua

@@ -1,24 +1,74 @@
-local function reduce(xs, value, f)
+local function append(xs, ys)
+  local result = {}
   for _, x in ipairs(xs) do
-    value = f(x, value)
+    table.insert(result, x)
+  end
+  for _, y in ipairs(ys) do
+    table.insert(result, y)
+  end
+  return result
+end
+
+local function concat(...)
+  local result = {}
+  for _, list in ipairs({ ... }) do
+    for _, item in ipairs(list) do
+      table.insert(result, item)
+    end
+  end
+  return result
+end
+
+local function length(xs)
+  local count = 0
+  for _ in ipairs(xs) do
+    count = count + 1
+  end
+  return count
+end
+
+local function reverse(xs)
+  local result = {}
+  for i = #xs, 1, -1 do
+    table.insert(result, xs[i])
+  end
+  return result
+end
+
+local function foldl(xs, value, f)
+  for _, x in ipairs(xs) do
+    value = f(value, x)
   end
   return value
 end
 
+local function foldr(xs, value, f)
+  return foldl(reverse(xs), value, f)
+end
+
 local function map(xs, f)
-  return reduce(xs, {}, function(x, acc)
+  return foldl(xs, {}, function(acc, x)
     table.insert(acc, f(x))
     return acc
   end)
 end
 
 local function filter(xs, pred)
-  return reduce(xs, {}, function(x, acc)
+  return foldl(xs, {}, function(acc, x)
     if pred(x) then
       table.insert(acc, x)
     end
     return acc
   end)
 end
 
-return { map = map, reduce = reduce, filter = filter }
+return {
+  append = append,
+  concat = concat,
+  length = length,
+  reverse = reverse,
+  map = map,
+  foldl = foldl,
+  foldr = foldr,
+  filter = filter
+}

exercises/practice/list-ops/.meta/spec_generator.lua

@@ -0,0 +1,70 @@
+local function map(t, f)
+  local result = {}
+  for i, v in ipairs(t) do
+    result[i] = f(v)
+  end
+  return result
+end
+
+local function render_list(list)
+  if type(list) ~= 'table' then
+    return list
+  end
+
+  return '{' .. table.concat(map(list, render_list), ', ') .. '}'
+end
+
+local function render_function(s)
+  s = s:gsub('modulo', '%%')
+  local args, body = s:match('^(.+)%s*->%s*(.+)$')
+  return 'function' .. args .. ' return ' .. body .. ' end'
+end
+
+return {
+  module_name = 'list_ops',
+
+  generate_test = function(case)
+    if case.input.lists then
+      local template = [[
+        local expected = %s
+        local actual = list_ops.%s(%s)
+        assert.are.same(expected, actual)]]
+
+      return template:format(render_list(case.expected), case.property,
+                             render_list(table.concat(map(case.input.lists, render_list), ', ')))
+    elseif case.input.list1 and case.input.list2 then
+      local template = [[
+        local expected = %s
+        local actual = list_ops.%s(%s, %s)
+        assert.are.same(expected, actual)]]
+
+      return template:format(render_list(case.expected), case.property, render_list(case.input.list1),
+                             render_list(case.input.list2))
+    elseif case.input.list and case.input['function'] and case.input.initial then
+      local template = [[
+        local expected = %s
+        local actual = list_ops.%s(%s, %s, %s)
+        assert.are.same(expected, actual)]]
+
+      return template:format(render_list(case.expected), case.property, render_list(case.input.list),
+                             render_list(case.input.initial), render_function(case.input['function']))
+    elseif case.input.list and case.input['function'] then
+      local template = [[
+        local expected = %s
+        local actual = list_ops.%s(%s, %s)
+        assert.are.same(expected, actual)]]
+
+      return template:format(render_list(case.expected), case.property, render_list(case.input.list),
+                             render_function(case.input['function']))
+    elseif case.input.list then
+      local template = [[
+        local expected = %s
+        local actual = list_ops.%s(%s)
+        assert.are.same(expected, actual)]]
+
+      return template:format(render_list(case.expected), case.property, render_list(case.input.list))
+    else
+      error('Unhandled case')
+    end
+  end
+}

exercises/practice/list-ops/.meta/tests.toml

@@ -1,66 +1,103 @@
-# This is an auto-generated file. Regular comments will be removed when this
-# file is regenerated. Regenerating will not touch any manually added keys,
-# so comments can be added in a "comment" key.
+# 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.
 
 [485b9452-bf94-40f7-a3db-c3cf4850066a]
-description = "empty lists"
+description = "append entries to a list and return the new list -> empty lists"
 
 [2c894696-b609-4569-b149-8672134d340a]
-description = "list to empty list"
+description = "append entries to a list and return the new list -> list to empty list"
 
 [71dcf5eb-73ae-4a0e-b744-a52ee387922f]
-description = "non-empty lists"
+description = "append entries to a list and return the new list -> non-empty lists"
 
 [28444355-201b-4af2-a2f6-5550227bde21]
-description = "empty list"
+description = "concatenate a list of lists -> empty list"
 
 [331451c1-9573-42a1-9869-2d06e3b389a9]
-description = "list of lists"
+description = "concatenate a list of lists -> list of lists"
 
 [d6ecd72c-197f-40c3-89a4-aa1f45827e09]
-description = "list of nested lists"
+description = "concatenate a list of lists -> list of nested lists"
 
 [0524fba8-3e0f-4531-ad2b-f7a43da86a16]
-description = "empty list"
+description = "filter list returning only values that satisfy the filter function -> empty list"
 
 [88494bd5-f520-4edb-8631-88e415b62d24]
-description = "non-empty list"
+description = "filter list returning only values that satisfy the filter function -> non-empty list"
 
 [1cf0b92d-8d96-41d5-9c21-7b3c37cb6aad]
-description = "empty list"
+description = "returns the length of a list -> empty list"
 
 [d7b8d2d9-2d16-44c4-9a19-6e5f237cb71e]
-description = "non-empty list"
+description = "returns the length of a list -> non-empty list"
 
 [c0bc8962-30e2-4bec-9ae4-668b8ecd75aa]
-description = "empty list"
+description = "return a list of elements whose values equal the list value transformed by the mapping function -> empty list"
 
 [11e71a95-e78b-4909-b8e4-60cdcaec0e91]
-description = "non-empty list"
+description = "return a list of elements whose values equal the list value transformed by the mapping function -> non-empty list"
 
 [613b20b7-1873-4070-a3a6-70ae5f50d7cc]
-description = "empty list"
+description = "folds (reduces) the given list from the left with a function -> empty list"
+include = false
 
 [e56df3eb-9405-416a-b13a-aabb4c3b5194]
-description = "direction independent function applied to non-empty list"
+description = "folds (reduces) the given list from the left with a function -> direction independent function applied to non-empty list"
+include = false
 
 [d2cf5644-aee1-4dfc-9b88-06896676fe27]
-description = "direction dependent function applied to non-empty list"
+description = "folds (reduces) the given list from the left with a function -> direction dependent function applied to non-empty list"
+include = false
+
+[36549237-f765-4a4c-bfd9-5d3a8f7b07d2]
+description = "folds (reduces) the given list from the left with a function -> empty list"
+reimplements = "613b20b7-1873-4070-a3a6-70ae5f50d7cc"
+
+[7a626a3c-03ec-42bc-9840-53f280e13067]
+description = "folds (reduces) the given list from the left with a function -> direction independent function applied to non-empty list"
+reimplements = "e56df3eb-9405-416a-b13a-aabb4c3b5194"
+
+[d7fcad99-e88e-40e1-a539-4c519681f390]
+description = "folds (reduces) the given list from the left with a function -> direction dependent function applied to non-empty list"
+reimplements = "d2cf5644-aee1-4dfc-9b88-06896676fe27"
 
 [aeb576b9-118e-4a57-a451-db49fac20fdc]
-description = "empty list"
+description = "folds (reduces) the given list from the right with a function -> empty list"
+include = false
 
 [c4b64e58-313e-4c47-9c68-7764964efb8e]
-description = "direction independent function applied to non-empty list"
+description = "folds (reduces) the given list from the right with a function -> direction independent function applied to non-empty list"
+include = false
 
 [be396a53-c074-4db3-8dd6-f7ed003cce7c]
-description = "direction dependent function applied to non-empty list"
+description = "folds (reduces) the given list from the right with a function -> direction dependent function applied to non-empty list"
+include = false
+
+[17214edb-20ba-42fc-bda8-000a5ab525b0]
+description = "folds (reduces) the given list from the right with a function -> empty list"
+reimplements = "aeb576b9-118e-4a57-a451-db49fac20fdc"
+
+[e1c64db7-9253-4a3d-a7c4-5273b9e2a1bd]
+description = "folds (reduces) the given list from the right with a function -> direction independent function applied to non-empty list"
+reimplements = "c4b64e58-313e-4c47-9c68-7764964efb8e"
+
+[8066003b-f2ff-437e-9103-66e6df474844]
+description = "folds (reduces) the given list from the right with a function -> direction dependent function applied to non-empty list"
+reimplements = "be396a53-c074-4db3-8dd6-f7ed003cce7c"
 
 [94231515-050e-4841-943d-d4488ab4ee30]
-description = "empty list"
+description = "reverse the elements of the list -> empty list"
 
 [fcc03d1e-42e0-4712-b689-d54ad761f360]
-description = "non-empty list"
+description = "reverse the elements of the list -> non-empty list"
 
 [40872990-b5b8-4cb8-9085-d91fc0d05d26]
-description = "list of lists is not flattened"
+description = "reverse the elements of the list -> list of lists is not flattened"

exercises/practice/list-ops/list-ops.lua

@@ -1,10 +1,42 @@
-local function reduce(xs, value, f)
+local function append(xs, ys)
+
+end
+
+local function concat(...)
+
+end
+
+local function length(xs)
+
+end
+
+local function reverse(xs)
+
+end
+
+local function foldl(xs, value, f)
+
+end
+
+local function foldr(xs, value, f)
+
 end
 
 local function map(xs, f)
+
 end
 
 local function filter(xs, pred)
+
 end
 
-return { map = map, reduce = reduce, filter = filter }
+return {
+  append = append,
+  concat = concat,
+  length = length,
+  reverse = reverse,
+  map = map,
+  foldl = foldl,
+  foldr = foldr,
+  filter = filter
+}