Prevent vocabulary terms conflicting with Elixir semantics

lib/rdf/vocabulary_namespace.ex

@@ -5,7 +5,7 @@ defmodule RDF.Vocabulary.Namespace do
   `RDF.Vocabulary.Namespace` modules represent a RDF vocabulary as a `RDF.Namespace`.
   They can be defined with the `defvocab/2` macro of this module.
 
-  RDF.ex comes with predefined modules for some fundamentals vocabularies in
+  RDF.ex comes with predefined modules for some fundamental vocabularies in
   the `RDF.NS` module.
   Furthermore, the [rdf_vocab](https://hex.pm/packages/rdf_vocab) package
   contains predefined modules for popular vocabularies.
@@ -44,7 +44,8 @@ defmodule RDF.Vocabulary.Namespace do
       terms
       |> term_mapping!(opts)
       |> Map.drop(MapSet.to_list(ignored_terms))
-      |> validate_terms!(opts)
+      |> validate_terms!
+      |> validate_characters!(opts)
       |> validate_case!(data, base_uri, opts)
     case_separated_terms = group_terms_by_case(terms)
     lowercased_terms  = Map.get(case_separated_terms, :lowercased, %{})
@@ -127,6 +128,10 @@ defmodule RDF.Vocabulary.Namespace do
   @doc false
   defmacro define_vocab_terms(terms, base_uri) do
     terms
+    |> Stream.filter(fn
+        {term, true}          -> valid_term?(term)
+        {term, original_term} -> true
+       end)
     |> Stream.map(fn
         {term, true}          -> {term, term}
         {term, original_term} -> {term, original_term}
@@ -204,6 +209,21 @@ defmodule RDF.Vocabulary.Namespace do
   end
 
 
+  defp ignored_terms!(opts) do
+    # TODO: find an alternative to Code.eval_quoted - We want to support that the terms can be given as sigils ...
+    with terms = Keyword.get(opts, :ignore, []) do
+      {terms, _ } = Code.eval_quoted(terms, [], rdf_data_env())
+      terms
+      |> Enum.map(fn
+           term when is_atom(term)   -> term
+           term when is_binary(term) -> String.to_atom(term)
+           term -> raise RDF.Namespace.InvalidTermError, inspect(term)
+         end)
+      |> MapSet.new
+    end
+  end
+
+
   defp term_mapping!(terms, opts) do
     terms = Map.new terms, fn
       term when is_atom(term) -> {term, true}
@@ -213,7 +233,7 @@ defmodule RDF.Vocabulary.Namespace do
     |> Enum.reduce(terms, fn {alias, original_term}, terms ->
          term = String.to_atom(original_term)
          cond do
-           not valid_term?(alias) ->
+           not valid_characters?(alias) ->
              raise RDF.Namespace.InvalidAliasError,
                "alias '#{alias}' contains invalid characters"
 
@@ -243,28 +263,85 @@ defmodule RDF.Vocabulary.Namespace do
     |> Enum.map(&String.to_atom/1)
   end
 
-  defp validate_terms!(terms, opts) do
+  @invalid_terms MapSet.new ~w[
+    and
+    or
+    xor
+    in
+    fn
+    def
+    when
+    if
+    for
+    case
+    with
+    quote
+    unquote
+    unquote_splicing
+    alias
+    import
+    require
+    super
+    __aliases__
+  ]a
+
+  def invalid_terms, do: @invalid_terms
+
+  defp validate_terms!(terms) do
+    aliased_terms = aliased_terms(terms)
+    terms
+    |> Enum.filter_map(
+         fn {term, _} ->
+           not term in aliased_terms and not valid_term?(term)
+         end,
+         fn {term, _} -> term end)
+    |> handle_invalid_terms!
+
+    terms
+  end
+
+  defp valid_term?(term) do
+    not MapSet.member?(@invalid_terms, term)
+  end
+
+  defp handle_invalid_terms!([]), do: nil
+
+  defp handle_invalid_terms!(invalid_terms) do
+    raise RDF.Namespace.InvalidTermError, """
+      The following terms can not be used, because they conflict with the Elixir semantics:
+
+      - #{Enum.join(invalid_terms, "\n- ")}
+
+      You have the following options:
+
+      - define an alias with the :alias option on defvocab
+      - ignore the resource with the :ignore option on defvocab
+      """
+  end
+
+
+  defp validate_characters!(terms, opts) do
     if (handling = Keyword.get(opts, :invalid_characters, :fail)) == :ignore do
       terms
     else
       terms
-      |> detect_invalid_terms
+      |> detect_invalid_characters
-      |> handle_invalid_terms(handling, terms)
+      |> handle_invalid_characters(handling, terms)
     end
   end
 
-  defp detect_invalid_terms(terms) do
+  defp detect_invalid_characters(terms) do
     aliased_terms = aliased_terms(terms)
     Enum.filter_map terms,
       fn {term, _} ->
-        not term in aliased_terms and not valid_term?(term)
+        not term in aliased_terms and not valid_characters?(term)
       end,
       fn {term, _} -> term end
   end
 
-  defp handle_invalid_terms([], _, terms), do: terms
+  defp handle_invalid_characters([], _, terms), do: terms
 
-  defp handle_invalid_terms(invalid_terms, :fail, _) do
+  defp handle_invalid_characters(invalid_terms, :fail, _) do
     raise RDF.Namespace.InvalidTermError, """
       The following terms contain invalid characters:
 
@@ -275,19 +352,20 @@ defmodule RDF.Vocabulary.Namespace do
       - if you are in control of the vocabulary, consider renaming the resource
       - define an alias with the :alias option on defvocab
       - change the handling of invalid characters with the :invalid_characters option on defvocab
+      - ignore the resource with the :ignore option on defvocab
       """
   end
 
-  defp handle_invalid_terms(invalid_terms, :warn, terms) do
+  defp handle_invalid_characters(invalid_terms, :warn, terms) do
     Enum.each invalid_terms, fn term ->
       IO.warn "'#{term}' is not valid term, since it contains invalid characters"
     end
     terms
   end
 
-  defp valid_term?(term) when is_atom(term),
+  defp valid_characters?(term) when is_atom(term),
-    do: valid_term?(Atom.to_string(term))
+    do: valid_characters?(Atom.to_string(term))
-  defp valid_term?(term),
+  defp valid_characters?(term),
     do: Regex.match?(~r/^[a-zA-Z_]\w*$/, term)
 
   defp validate_case!(terms, nil, _, _), do: terms
@@ -405,6 +483,7 @@ defmodule RDF.Vocabulary.Namespace do
       - if you are in control of the vocabulary, consider renaming the resource
       - define a properly cased alias with the :alias option on defvocab
       - change the handling of case violations with the :case_violations option on defvocab
+      - ignore the resource with the :ignore option on defvocab
       """
   end
 
@@ -434,20 +513,6 @@ defmodule RDF.Vocabulary.Namespace do
   end
 
 
-  defp ignored_terms!(opts) do
-    # TODO: find an alternative to Code.eval_quoted - We want to support that the terms can be given as sigils ...
-    with terms = Keyword.get(opts, :ignore, []) do
-      {terms, _ } = Code.eval_quoted(terms, [], rdf_data_env())
-      terms
-      |> Enum.map(fn
-           term when is_atom(term)   -> term
-           term when is_binary(term) -> String.to_atom(term)
-           term -> raise RDF.Namespace.InvalidTermError, inspect(term)
-         end)
-      |> MapSet.new
-    end
-  end
-
   defp filename!(opts) do
     if filename = Keyword.get(opts, :file) do
       cond do

test/unit/vocabulary_namespace_test.exs

@@ -141,22 +141,6 @@ defmodule RDF.Vocabulary.NamespaceTest do
   end
 
 
-  test "defvocab with special terms" do
-    defmodule NSofEdgeCases do
-      use RDF.Vocabulary.Namespace
-
-      defvocab Example,
-        base_uri: "http://example.com/ex#",
-        terms: ~w[nil true false]
-    end
-    alias NSofEdgeCases.Example
-
-    assert Example.nil == ~I<http://example.com/ex#nil>
-    assert Example.true == ~I<http://example.com/ex#true>
-    assert Example.false == ~I<http://example.com/ex#false>
-  end
-
-
   describe "defvocab with bad aliases" do
     test "when an alias contains invalid characters, an error is raised" do
       assert_raise RDF.Namespace.InvalidAliasError, fn ->
@@ -212,10 +196,190 @@ defmodule RDF.Vocabulary.NamespaceTest do
   end
 
 
+  test "defvocab with special terms" do
+    defmodule NSofEdgeCases do
+      use RDF.Vocabulary.Namespace
+
+      defvocab Example,
+        base_uri: "http://example.com/ex#",
+        terms: ~w[
+          nil
+          true
+          false
+          do
+          end
+          else
+          try
+          rescue
+          catch
+          after
+          not
+          cond
+          inbits
+          inlist
+          receive
+          __block__
+          __info__
+          __MODULE__
+          __FILE__
+          __DIR__
+          __ENV__
+          __CALLER__
+        ]
+    end
+    alias NSofEdgeCases.Example
+    alias TestNS.EX
+
+    assert Example.nil     == ~I<http://example.com/ex#nil>
+    assert Example.true    == ~I<http://example.com/ex#true>
+    assert Example.false   == ~I<http://example.com/ex#false>
+    assert Example.do      == ~I<http://example.com/ex#do>
+    assert Example.end     == ~I<http://example.com/ex#end>
+    assert Example.else    == ~I<http://example.com/ex#else>
+    assert Example.try     == ~I<http://example.com/ex#try>
+    assert Example.rescue  == ~I<http://example.com/ex#rescue>
+    assert Example.catch   == ~I<http://example.com/ex#catch>
+    assert Example.after   == ~I<http://example.com/ex#after>
+    assert Example.not     == ~I<http://example.com/ex#not>
+    assert Example.cond    == ~I<http://example.com/ex#cond>
+    assert Example.inbits  == ~I<http://example.com/ex#inbits>
+    assert Example.inlist  == ~I<http://example.com/ex#inlist>
+    assert Example.receive == ~I<http://example.com/ex#receive>
+    assert Example.__block__   == ~I<http://example.com/ex#__block__>
+    assert Example.__info__    == ~I<http://example.com/ex#__info__>
+    assert Example.__MODULE__  == ~I<http://example.com/ex#__MODULE__>
+    assert Example.__FILE__    == ~I<http://example.com/ex#__FILE__>
+    assert Example.__DIR__     == ~I<http://example.com/ex#__DIR__>
+    assert Example.__ENV__     == ~I<http://example.com/ex#__ENV__>
+    assert Example.__CALLER__  == ~I<http://example.com/ex#__CALLER__>
+
+    assert Example.nil(    EX.S, 1) == RDF.description(EX.S, Example.nil     , 1)
+    assert Example.true(   EX.S, 1) == RDF.description(EX.S, Example.true    , 1)
+    assert Example.false(  EX.S, 1) == RDF.description(EX.S, Example.false   , 1)
+    assert Example.do(     EX.S, 1) == RDF.description(EX.S, Example.do      , 1)
+    assert Example.end(    EX.S, 1) == RDF.description(EX.S, Example.end     , 1)
+    assert Example.else(   EX.S, 1) == RDF.description(EX.S, Example.else    , 1)
+    assert Example.try(    EX.S, 1) == RDF.description(EX.S, Example.try     , 1)
+    assert Example.rescue( EX.S, 1) == RDF.description(EX.S, Example.rescue  , 1)
+    assert Example.catch(  EX.S, 1) == RDF.description(EX.S, Example.catch   , 1)
+    assert Example.after(  EX.S, 1) == RDF.description(EX.S, Example.after   , 1)
+    assert Example.not(    EX.S, 1) == RDF.description(EX.S, Example.not     , 1)
+    assert Example.cond(   EX.S, 1) == RDF.description(EX.S, Example.cond    , 1)
+    assert Example.inbits( EX.S, 1) == RDF.description(EX.S, Example.inbits  , 1)
+    assert Example.inlist( EX.S, 1) == RDF.description(EX.S, Example.inlist  , 1)
+    assert Example.receive(EX.S, 1) == RDF.description(EX.S, Example.receive , 1)
+  end
+
+
+  describe "defvocab with invalid terms" do
+    test "terms with a special meaning for Elixir cause a failure" do
+      assert_raise RDF.Namespace.InvalidTermError, ~r/unquote_splicing/s, fn ->
+        defmodule NSWithElixirTerms do
+          use RDF.Vocabulary.Namespace
+          defvocab Example,
+            base_uri: "http://example.com/example#",
+            terms: RDF.Vocabulary.Namespace.invalid_terms
+        end
+      end
+    end
+
+    test "alias terms with a special meaning for Elixir cause a failure" do
+      assert_raise RDF.Namespace.InvalidTermError, ~r/unquote_splicing/s, fn ->
+        defmodule NSWithElixirAliasTerms do
+          use RDF.Vocabulary.Namespace
+          defvocab Example,
+            base_uri: "http://example.com/example#",
+             terms: ~w[foo],
+              alias: [
+                      and:              "foo",
+                      or:               "foo",
+                      xor:              "foo",
+                      in:               "foo",
+                      fn:               "foo",
+                      def:              "foo",
+                      when:             "foo",
+                      if:               "foo",
+                      for:              "foo",
+                      case:             "foo",
+                      with:             "foo",
+                      quote:            "foo",
+                      unquote:          "foo",
+                      unquote_splicing: "foo",
+                      alias:            "foo",
+                      import:           "foo",
+                      require:          "foo",
+                      super:            "foo",
+                      __aliases__:      "foo",
+                    ]
+        end
+      end
+    end
+
+    test "terms with a special meaning for Elixir don't cause a failure when they are ignored" do
+      defmodule NSWithIgnoredElixirTerms do
+        use RDF.Vocabulary.Namespace
+        defvocab Example,
+          base_uri: "http://example.com/example#",
+          terms: RDF.Vocabulary.Namespace.invalid_terms,
+          ignore: RDF.Vocabulary.Namespace.invalid_terms
+      end
+    end
+
+    test "terms with a special meaning for Elixir don't cause a failure when an alias is defined" do
+      defmodule NSWithAliasesForElixirTerms do
+        use RDF.Vocabulary.Namespace
+        defvocab Example,
+          base_uri: "http://example.com/example#",
+          terms: RDF.Vocabulary.Namespace.invalid_terms,
+          alias: [
+                   and_:              "and",
+                   or_:               "or",
+                   xor_:              "xor",
+                   in_:               "in",
+                   fn_:               "fn",
+                   def_:              "def",
+                   when_:             "when",
+                   if_:               "if",
+                   for_:              "for",
+                   case_:             "case",
+                   with_:             "with",
+                   quote_:            "quote",
+                   unquote_:          "unquote",
+                   unquote_splicing_: "unquote_splicing",
+                   alias_:            "alias",
+                   import_:           "import",
+                   require_:          "require",
+                   super_:            "super",
+                   _aliases_:         "__aliases__"
+                 ]
+      end
+      alias NSWithAliasesForElixirTerms.Example
+
+      assert Example.and_              == ~I<http://example.com/example#and>
+      assert Example.or_               == ~I<http://example.com/example#or>
+      assert Example.xor_              == ~I<http://example.com/example#xor>
+      assert Example.in_               == ~I<http://example.com/example#in>
+      assert Example.fn_               == ~I<http://example.com/example#fn>
+      assert Example.def_              == ~I<http://example.com/example#def>
+      assert Example.when_             == ~I<http://example.com/example#when>
+      assert Example.if_               == ~I<http://example.com/example#if>
+      assert Example.for_              == ~I<http://example.com/example#for>
+      assert Example.case_             == ~I<http://example.com/example#case>
+      assert Example.with_             == ~I<http://example.com/example#with>
+      assert Example.quote_            == ~I<http://example.com/example#quote>
+      assert Example.unquote_          == ~I<http://example.com/example#unquote>
+      assert Example.unquote_splicing_ == ~I<http://example.com/example#unquote_splicing>
+      assert Example.alias_            == ~I<http://example.com/example#alias>
+      assert Example.import_           == ~I<http://example.com/example#import>
+      assert Example.require_          == ~I<http://example.com/example#require>
+      assert Example.super_            == ~I<http://example.com/example#super>
+      assert Example._aliases_         == ~I<http://example.com/example#__aliases__>
+    end
+  end
+
   describe "defvocab invalid character handling" do
     test "when a term contains unallowed characters and no alias defined, it fails when invalid_characters = :fail" do
-      assert_raise RDF.Namespace.InvalidTermError, ~r/Foo-bar.*foo-bar/s,
+      assert_raise RDF.Namespace.InvalidTermError, ~r/Foo-bar.*foo-bar/s, fn ->
-        fn ->
         defmodule NSWithInvalidTerms1 do
           use RDF.Vocabulary.Namespace
           defvocab Example,
@@ -274,7 +438,6 @@ defmodule RDF.Vocabulary.NamespaceTest do
       end
     end
 
-
     test "a capitalized property without an alias and :case_violations == :fail, raises an error" do
       assert_raise RDF.Namespace.InvalidTermError, ~r<http://example\.com/ex#Foo>s, fn ->
         defmodule NSWithBadCasedTerms3 do
@@ -485,7 +648,7 @@ defmodule RDF.Vocabulary.NamespaceTest do
     end
 
     test "ignored terms with case violations do not raise anything" do
-      defmodule IgnoredTermWithInvalidCharacters do
+      defmodule IgnoredTermWithCaseViolations do
         use RDF.Vocabulary.Namespace
         defvocab Example,
           base_uri: "http://example.com/",