Add support for RDF.PropertyMaps in BGP and path queries

CHANGELOG.md

@@ -20,8 +20,8 @@ are specified.
 
 - `RDF.PropertyMap` which allow definition of atoms for RDF properties. 
   Such property maps can be provided to all RDF data structure functions 
-  accepting input data with the `:context` opt, allowing the use of the atoms
-  from the property map in the input data. 
+  accepting input data and BGP query patterns with the `:context` opt, 
+  allowing the use of the atoms from the property map in the input data. 
 - to `RDF.Description`
     - `RDF.Description.subject/1` 
     - `RDF.Description.change_subject/2`

lib/rdf/query.ex

@@ -73,7 +73,7 @@ defmodule RDF.Query do
   end
 
   def execute(query, graph, opts) do
-    with {:ok, bgp} <- Builder.bgp(query) do
+    with {:ok, bgp} <- Builder.bgp(query, opts) do
       execute(bgp, graph, opts)
     end
   end
@@ -141,7 +141,7 @@ defmodule RDF.Query do
   end
 
   def stream(query, graph, opts) do
-    with {:ok, bgp} <- Builder.bgp(query) do
+    with {:ok, bgp} <- Builder.bgp(query, opts) do
       stream(bgp, graph, opts)
     end
   end

lib/rdf/query/builder.ex

@@ -2,51 +2,53 @@ defmodule RDF.Query.Builder do
   @moduledoc false
 
   alias RDF.Query.BGP
-  alias RDF.{IRI, BlankNode, Literal, Namespace}
+  alias RDF.{IRI, BlankNode, Literal, Namespace, PropertyMap}
   import RDF.Utils.Guards
   import RDF.Utils
 
-  def bgp(query) do
-    with {:ok, triple_patterns} <- triple_patterns(query) do
+  def bgp(query, opts \\ []) do
+    property_map = if context = Keyword.get(opts, :context), do: PropertyMap.new(context)
+
+    with {:ok, triple_patterns} <- triple_patterns(query, property_map) do
       {:ok, %BGP{triple_patterns: triple_patterns}}
     end
   end
 
-  def bgp!(query) do
-    case bgp(query) do
+  def bgp!(query, opts \\ []) do
+    case bgp(query, opts) do
       {:ok, bgp} -> bgp
       {:error, error} -> raise error
     end
   end
 
-  defp triple_patterns(query) when is_list(query) or is_map(query) do
+  defp triple_patterns(query, property_map) when is_list(query) or is_map(query) do
     flat_map_while_ok(query, fn triple ->
-      with {:ok, triple_pattern} <- triple_patterns(triple) do
+      with {:ok, triple_pattern} <- triple_patterns(triple, property_map) do
         {:ok, List.wrap(triple_pattern)}
       end
     end)
   end
 
-  defp triple_patterns({subject, predicate, objects}) do
+  defp triple_patterns({subject, predicate, objects}, property_map) do
     with {:ok, subject_pattern} <- subject_pattern(subject) do
-      do_triple_patterns(subject_pattern, {predicate, objects})
+      do_triple_patterns(subject_pattern, {predicate, objects}, property_map)
     end
   end
 
-  defp triple_patterns({subject, predications}) when is_map(predications) do
-    triple_patterns({subject, Map.to_list(predications)})
+  defp triple_patterns({subject, predications}, property_map) when is_map(predications) do
+    triple_patterns({subject, Map.to_list(predications)}, property_map)
   end
 
-  defp triple_patterns({subject, predications}) do
+  defp triple_patterns({subject, predications}, property_map) do
     with {:ok, subject_pattern} <- subject_pattern(subject) do
       predications
       |> List.wrap()
-      |> flat_map_while_ok(&do_triple_patterns(subject_pattern, &1))
+      |> flat_map_while_ok(&do_triple_patterns(subject_pattern, &1, property_map))
     end
   end
 
-  defp do_triple_patterns(subject_pattern, {predicate, objects}) do
-    with {:ok, predicate_pattern} <- predicate_pattern(predicate) do
+  defp do_triple_patterns(subject_pattern, {predicate, objects}, property_map) do
+    with {:ok, predicate_pattern} <- predicate_pattern(predicate, property_map) do
       objects
       |> List.wrap()
       |> map_while_ok(fn object ->
@@ -70,8 +72,8 @@ defmodule RDF.Query.Builder do
     end
   end
 
-  defp predicate_pattern(predicate) do
-    value = variable(predicate) || resource(predicate) || property(predicate)
+  defp predicate_pattern(predicate, property_map) do
+    value = variable(predicate) || resource(predicate) || property(predicate, property_map)
 
     if value do
       {:ok, value}
@@ -127,8 +129,13 @@ defmodule RDF.Query.Builder do
 
   defp resource(_), do: nil
 
-  defp property(:a), do: RDF.type()
-  defp property(_), do: nil
+  defp property(:a, _), do: RDF.type()
+
+  defp property(term, property_map) when is_atom(term) and not is_nil(property_map) do
+    PropertyMap.iri(property_map, term)
+  end
+
+  defp property(_, _), do: nil
 
   defp literal(%Literal{} = literal), do: literal
   defp literal(value), do: Literal.coerce(value)
@@ -144,7 +151,7 @@ defmodule RDF.Query.Builder do
 
   def path([subject | rest], opts) do
     path_pattern(subject, rest, [], 0, Keyword.get(opts, :with_elements, false))
-    |> bgp()
+    |> bgp(opts)
   end
 
   def path!(query, opts \\ []) do

test/unit/query/builder_test.exs

@@ -212,6 +212,30 @@ defmodule RDF.Query.BuilderTest do
                  {~B"s", :p, :o}
                ])
     end
+
+    test "with contexts" do
+      assert Builder.bgp(
+               %{
+                 s?: %{
+                   p1: :o?,
+                   p2: [42, true]
+                 },
+                 o?: [p3: ["foo", "bar"]]
+               },
+               context: %{
+                 p1: EX.p1(),
+                 p2: EX.p2(),
+                 p3: EX.p3()
+               }
+             ) ==
+               ok_bgp_struct([
+                 {:o, EX.p3(), ~L"foo"},
+                 {:o, EX.p3(), ~L"bar"},
+                 {:s, EX.p1(), :o},
+                 {:s, EX.p2(), XSD.integer(42)},
+                 {:s, EX.p2(), XSD.true()}
+               ])
+    end
   end
 
   describe "path/2" do
@@ -247,5 +271,24 @@ defmodule RDF.Query.BuilderTest do
                  {:el0, EX.p2(), :o}
                ])
     end
+
+    test "with contexts" do
+      property_map = %{
+        p1: EX.p1(),
+        p2: EX.p2()
+      }
+
+      assert Builder.path([EX.s(), :p1, :p2, EX.o()], context: property_map) ==
+               ok_bgp_struct([
+                 {EX.s(), EX.p1(), RDF.bnode("0")},
+                 {RDF.bnode("0"), EX.p2(), EX.o()}
+               ])
+
+      assert Builder.path([EX.s(), :p1, :p2, :o?], context: property_map, with_elements: true) ==
+               ok_bgp_struct([
+                 {EX.s(), EX.p1(), :el0},
+                 {:el0, EX.p2(), :o}
+               ])
+    end
   end
 end