Macroless / Native CTE

.credo.exs

@@ -0,0 +1,153 @@
+# This file contains the configuration for Credo and you are probably reading
+# this after creating it with `mix credo.gen.config`.
+#
+# If you find anything wrong or unclear in this file, please report an
+# issue on GitHub: https://github.com/rrrene/credo/issues
+#
+%{
+  #
+  # You can have as many configs as you like in the `configs:` field.
+  configs: [
+    %{
+      #
+      # Run any exec using `mix credo -C <name>`. If no exec name is given
+      # "default" is used.
+      #
+      name: "default",
+      #
+      # These are the files included in the analysis:
+      files: %{
+        #
+        # You can give explicit globs or simply directories.
+        # In the latter case `**/*.{ex,exs}` will be used.
+        #
+        included: ["lib/", "src/", "test/", "web/", "apps/"],
+        excluded: [~r"/_build/", ~r"/deps/", ~r"/node_modules/"]
+      },
+      #
+      # If you create your own checks, you must specify the source files for
+      # them here, so they can be loaded by Credo before running the analysis.
+      #
+      requires: [],
+      #
+      # If you want to enforce a style guide and need a more traditional linting
+      # experience, you can change `strict` to `true` below:
+      #
+      strict: false,
+      #
+      # If you want to use uncolored output by default, you can change `color`
+      # to `false` below:
+      #
+      color: true,
+      #
+      # You can customize the parameters of any check by adding a second element
+      # to the tuple.
+      #
+      # To disable a check put `false` as second element:
+      #
+      #     {Credo.Check.Design.DuplicatedCode, false}
+      #
+      checks: [
+        #
+        ## Consistency Checks
+        #
+        {Credo.Check.Consistency.ExceptionNames, []},
+        {Credo.Check.Consistency.LineEndings, []},
+        {Credo.Check.Consistency.ParameterPatternMatching, []},
+        {Credo.Check.Consistency.SpaceAroundOperators, []},
+        {Credo.Check.Consistency.SpaceInParentheses, []},
+        {Credo.Check.Consistency.TabsOrSpaces, []},
+
+        #
+        ## Design Checks
+        #
+        # You can customize the priority of any check
+        # Priority values are: `low, normal, high, higher`
+        #
+        {Credo.Check.Design.AliasUsage,
+         [priority: :low, if_nested_deeper_than: 2, if_called_more_often_than: 0]},
+        # You can also customize the exit_status of each check.
+        # If you don't want TODO comments to cause `mix credo` to fail, just
+        # set this value to 0 (zero).
+        #
+        {Credo.Check.Design.TagTODO, [exit_status: 2]},
+        {Credo.Check.Design.TagFIXME, []},
+
+        #
+        ## Readability Checks
+        #
+        {Credo.Check.Readability.AliasOrder, []},
+        {Credo.Check.Readability.FunctionNames, []},
+        {Credo.Check.Readability.LargeNumbers, []},
+        {Credo.Check.Readability.MaxLineLength, [priority: :low, max_length: 120]},
+        {Credo.Check.Readability.ModuleAttributeNames, []},
+        {Credo.Check.Readability.ModuleDoc, []},
+        {Credo.Check.Readability.ModuleNames, []},
+        {Credo.Check.Readability.ParenthesesInCondition, []},
+        {Credo.Check.Readability.ParenthesesOnZeroArityDefs, []},
+        {Credo.Check.Readability.PredicateFunctionNames, []},
+        {Credo.Check.Readability.PreferImplicitTry, []},
+        {Credo.Check.Readability.RedundantBlankLines, []},
+        {Credo.Check.Readability.Semicolons, []},
+        {Credo.Check.Readability.SpaceAfterCommas, []},
+        {Credo.Check.Readability.StringSigils, []},
+        {Credo.Check.Readability.TrailingBlankLine, []},
+        {Credo.Check.Readability.TrailingWhiteSpace, []},
+        {Credo.Check.Readability.VariableNames, []},
+
+        #
+        ## Refactoring Opportunities
+        #
+        {Credo.Check.Refactor.CondStatements, []},
+        {Credo.Check.Refactor.CyclomaticComplexity, []},
+        {Credo.Check.Refactor.FunctionArity, []},
+        {Credo.Check.Refactor.LongQuoteBlocks, []},
+        {Credo.Check.Refactor.MapInto, []},
+        {Credo.Check.Refactor.MatchInCondition, []},
+        {Credo.Check.Refactor.NegatedConditionsInUnless, []},
+        {Credo.Check.Refactor.NegatedConditionsWithElse, []},
+        {Credo.Check.Refactor.Nesting, []},
+        {Credo.Check.Refactor.PipeChainStart,
+         [excluded_argument_types: [:atom, :binary, :fn, :keyword], excluded_functions: []]},
+        {Credo.Check.Refactor.UnlessWithElse, []},
+
+        #
+        ## Warnings
+        #
+        {Credo.Check.Warning.BoolOperationOnSameValues, []},
+        {Credo.Check.Warning.ExpensiveEmptyEnumCheck, []},
+        {Credo.Check.Warning.IExPry, []},
+        {Credo.Check.Warning.IoInspect, []},
+        {Credo.Check.Warning.LazyLogging, []},
+        {Credo.Check.Warning.OperationOnSameValues, []},
+        {Credo.Check.Warning.OperationWithConstantResult, []},
+        {Credo.Check.Warning.RaiseInsideRescue, []},
+        {Credo.Check.Warning.UnusedEnumOperation, []},
+        {Credo.Check.Warning.UnusedFileOperation, []},
+        {Credo.Check.Warning.UnusedKeywordOperation, []},
+        {Credo.Check.Warning.UnusedListOperation, []},
+        {Credo.Check.Warning.UnusedPathOperation, []},
+        {Credo.Check.Warning.UnusedRegexOperation, []},
+        {Credo.Check.Warning.UnusedStringOperation, []},
+        {Credo.Check.Warning.UnusedTupleOperation, []},
+
+        #
+        # Controversial and experimental checks (opt-in, just remove `, false`)
+        #
+        {Credo.Check.Consistency.MultiAliasImportRequireUse, false},
+        {Credo.Check.Design.DuplicatedCode, false},
+        {Credo.Check.Readability.Specs},
+        {Credo.Check.Refactor.ABCSize, false},
+        {Credo.Check.Refactor.AppendSingleItem, false},
+        {Credo.Check.Refactor.DoubleBooleanNegation, false},
+        {Credo.Check.Refactor.VariableRebinding, false},
+        {Credo.Check.Warning.MapGetUnsafePass, false},
+        {Credo.Check.Warning.UnsafeToAtom, false}
+
+        #
+        # Custom checks can be created using `mix credo.gen.check`.
+        #
+      ]
+    }
+  ]
+}

lib/arbor/adapters/postgres.ex

@@ -0,0 +1,70 @@
+defmodule Arbor.Adapters.Postgres do
+  @moduledoc """
+  Postgres tree adapter
+  """
+
+  import Ecto.Query
+
+  @doc """
+  Query for root level records.
+
+  ## Examples
+    Basic Usage:
+      iex> Arbor.Adapters.Postgres.roots(Arbor.Comment)
+      #Ecto.Query<from c0 in Arbor.Comment, where: is_nil(c0.parent_id)>
+
+    Providing parent foreign key name:
+      iex> Arbor.Adapters.Postgres.roots(Arbor.Folder, foreign_key: :parent_uuid)
+      #Ecto.Query<from c0 in Arbor.Comment, where: is_nil(c0.parent_id)>
+
+    Ad-hoc queries:
+      iex> Arbor.Adapters.Postgres.roots("comments")
+      #Ecto.Query<from c0 in "comments", where: is_nil(c0.parent_id)>
+
+    Composing queries:
+      iex> roots = Arbor.Adapters.Postgres.roots(Arbor.Comment)
+      ...> sorted_roots = Arbor.Comment.by_inserted_at(roots)
+      #Ecto.Query<from c0 in Arbor.Comment, where: is_nil(c0.parent_id), order_by: [asc: c0.inserted_at]>
+  """
+  @spec roots(module() | String.t(), Keyword.t()) :: Ecto.Query.t()
+  def roots(schema, opts \\ []) do
+    foreign_key = Keyword.get(opts, :foreign_key, :parent_id)
+    from(t in schema, where: is_nil(field(t, ^foreign_key)))
+  end
+
+  @doc """
+  Query for a child record's parent.
+
+  ## Examples
+  TODO: Add examples
+  """
+  @spec parent(struct(), Keyword.t()) :: Ecto.Query.t()
+  def parent(%{__meta__: meta} = child_struct, opts \\ []) do
+    schema = meta.schema
+    defaults = schema_defaults(schema)
+    merged_opts = Keyword.merge(defaults, opts)
+
+    primary_key = merged_opts[:primary_key]
+    foreign_key = merged_opts[:foreign_key]
+    foreign_key_type = merged_opts[:foreign_key_type]
+    foreign_key_value = Map.get(child_struct, foreign_key)
+
+    from(
+      t in schema,
+      where: field(t, ^primary_key) == type(^foreign_key_value, ^foreign_key_type)
+    )
+  end
+
+  # Generates defaults to be merged with opts given an ecto schema
+  defp schema_defaults(module) do
+    primary_key = :primary_key |> module.__schema__() |> List.first()
+    primary_key_type = module.__schema__(:type, primary_key)
+
+    [
+      primary_key: primary_key,
+      primary_key_type: primary_key_type,
+      foreign_key: :parent_id,
+      foreign_key_type: primary_key_type
+    ]
+  end
+end

lib/arbor/tree.ex

@@ -74,20 +74,18 @@ defmodule Arbor.Tree do
       import Ecto.Query
 
       def roots do
-        from(
-          t in unquote(definition),
-          where: fragment(unquote("#{opts[:foreign_key]} IS NULL"))
-        )
+        schema = unquote(definition)
+        foreign_key = unquote(opts[:foreign_key])
+        Arbor.Adapters.Postgres.roots(schema, foreign_key: foreign_key)
       end
 
       def parent(struct) do
-        from(
-          t in unquote(definition),
-          where:
-            fragment(
-              unquote("#{opts[:primary_key]} = ?"),
-              type(^struct.unquote(opts[:foreign_key]), unquote(opts[:foreign_key_type]))
-            )
+        o = unquote(opts)
+
+        Arbor.Adapters.Postgres.parent(struct,
+          foreign_key: o[:foreign_key],
+          parent_key: o[:parent_key],
+          foreign_key_type: o[:foreign_key_type]
         )
       end
 
@@ -117,28 +115,35 @@ defmodule Arbor.Tree do
       end
 
       def ancestors(struct) do
-        from t in unquote(definition),
-          join: g in fragment(unquote("""
-          (
-            WITH RECURSIVE #{opts[:tree_name]} AS (
-              SELECT #{opts[:primary_key]},
-                    #{opts[:foreign_key]},
-                    0 AS depth
-              FROM #{opts[:table_name]}
-              WHERE #{opts[:primary_key]} = ?
-            UNION ALL
-              SELECT #{opts[:table_name]}.#{opts[:primary_key]},
-                    #{opts[:table_name]}.#{opts[:foreign_key]},
-                    #{opts[:tree_name]}.depth + 1
-              FROM #{opts[:table_name]}
-                JOIN #{opts[:tree_name]}
-                ON #{opts[:tree_name]}.#{opts[:foreign_key]} = #{opts[:table_name]}.#{opts[:primary_key]}
-            )
-            SELECT *
-            FROM #{opts[:tree_name]}
-          )
-          """), type(^struct.unquote(opts[:primary_key]), unquote(opts[:primary_key_type]))),
+        from(t in unquote(definition),
+          join:
+            g in fragment(
+              unquote("""
+              (
+                WITH RECURSIVE #{opts[:tree_name]} AS (
+                  SELECT #{opts[:primary_key]},
+                        #{opts[:foreign_key]},
+                        0 AS depth
+                  FROM #{opts[:table_name]}
+                  WHERE #{opts[:primary_key]} = ?
+                UNION ALL
+                  SELECT #{opts[:table_name]}.#{opts[:primary_key]},
+                        #{opts[:table_name]}.#{opts[:foreign_key]},
+                        #{opts[:tree_name]}.depth + 1
+                  FROM #{opts[:table_name]}
+                    JOIN #{opts[:tree_name]}
+                    ON #{opts[:tree_name]}.#{opts[:foreign_key]} = #{opts[:table_name]}.#{
+                opts[:primary_key]
+              }
+                )
+                SELECT *
+                FROM #{opts[:tree_name]}
+              )
+              """),
+              type(^struct.unquote(opts[:primary_key]), unquote(opts[:primary_key_type]))
+            ),
           on: t.unquote(opts[:primary_key]) == g.unquote(opts[:foreign_key])
+        )
       end
 
       def descendants(struct, depth \\ 2_147_483_647) do

mix.exs

@@ -31,6 +31,11 @@ defmodule Arbor.Mixfile do
     [
       {:ecto_sql, ">= 3.0.0"},
       {:postgrex, ">= 0.0.0"},
+
+      ## Test / Dev
+      {:credo, "~> 1.0.0", only: [:dev, :test], runtime: false},
+      {:mix_test_watch, "~> 1.0", only: :dev, runtime: false},
+      {:dialyxir, "~> 0.5", only: [:dev], runtime: false},
       {:earmark, "~> 1.1", only: [:docs, :dev]},
       {:ex_doc, "~> 0.19", only: [:docs, :dev]}
     ]

mix.lock

@@ -1,13 +1,19 @@
 %{
+  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm"},
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
+  "credo": {:hex, :credo, "1.0.5", "fdea745579f8845315fe6a3b43e2f9f8866839cfbc8562bb72778e9fdaa94214", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
   "decimal": {:hex, :decimal, "1.8.0", "ca462e0d885f09a1c5a342dbd7c1dcf27ea63548c65a65e67334f4b61803822e", [:mix], [], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "0.5.1", "b331b091720fd93e878137add264bac4f644e1ddae07a70bf7062c7862c4b952", [:mix], [], "hexpm"},
   "earmark": {:hex, :earmark, "1.3.5", "0db71c8290b5bc81cb0101a2a507a76dca659513984d683119ee722828b424f6", [:mix], [], "hexpm"},
   "ecto": {:hex, :ecto, "3.1.7", "fa21d06ef56cdc2fdaa62574e8c3ba34a2751d44ea34c30bc65f0728421043e5", [:mix], [{:decimal, "~> 1.6", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm"},
   "ecto_sql": {:hex, :ecto_sql, "3.1.6", "1e80e30d16138a729c717f73dcb938590bcdb3a4502f3012414d0cbb261045d8", [:mix], [{:db_connection, "~> 2.0", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.1.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:mariaex, "~> 0.9.1", [hex: :mariaex, repo: "hexpm", optional: true]}, {:myxql, "~> 0.2.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.14.0 or ~> 0.15.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.21.1", "5ac36660846967cd869255f4426467a11672fec3d8db602c429425ce5b613b90", [:mix], [{:earmark, "~> 1.3", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
+  "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},
+  "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
   "makeup": {:hex, :makeup, "1.0.0", "671df94cf5a594b739ce03b0d0316aa64312cee2574b6a44becb83cd90fb05dc", [:mix], [{:nimble_parsec, "~> 0.5.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.14.0", "cf8b7c66ad1cff4c14679698d532f0b5d45a3968ffbcbfd590339cb57742f1ae", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
+  "mix_test_watch": {:hex, :mix_test_watch, "1.0.2", "34900184cbbbc6b6ed616ed3a8ea9b791f9fd2088419352a6d3200525637f785", [:mix], [{:file_system, "~> 0.2.1 or ~> 0.3", [hex: :file_system, repo: "hexpm", optional: false]}], "hexpm"},
   "nimble_parsec": {:hex, :nimble_parsec, "0.5.1", "c90796ecee0289dbb5ad16d3ad06f957b0cd1199769641c961cfe0b97db190e0", [:mix], [], "hexpm"},
   "postgrex": {:hex, :postgrex, "0.15.0", "dd5349161019caeea93efa42f9b22f9d79995c3a86bdffb796427b4c9863b0f0", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm"},
   "telemetry": {:hex, :telemetry, "0.4.0", "8339bee3fa8b91cb84d14c2935f8ecf399ccd87301ad6da6b71c09553834b2ab", [:rebar3], [], "hexpm"},