Change RDF.Datatype.cast implementations to return nil when not castable

lib/rdf/datatypes/boolean.ex

@@ -54,6 +54,8 @@ defmodule RDF.Boolean do
     end
   end
 
+  def cast(_), do: nil
+
 
   @doc """
   Returns `RDF.true` if the effective boolean value of the given argument is `RDF.false`, or `RDF.false` if it is `RDF.true`.

lib/rdf/datatypes/date.ex

@@ -86,4 +86,6 @@ defmodule RDF.Date do
     end
   end
 
+  def cast(_), do: nil
+
 end

lib/rdf/datatypes/date_time.ex

@@ -88,6 +88,8 @@ defmodule RDF.DateTime do
     end
   end
 
+  def cast(_), do: nil
+
 
   def tz(%Literal{value: %NaiveDateTime{}}), do: ""
 

lib/rdf/datatypes/decimal.ex

@@ -96,6 +96,8 @@ defmodule RDF.Decimal do
     end
   end
 
+  def cast(_), do: nil
+
 
   def equal_value?(left, right), do: RDF.Numeric.equal_value?(left, right)
 

lib/rdf/datatypes/double.ex

@@ -128,6 +128,8 @@ defmodule RDF.Double do
     end
   end
 
+  def cast(_), do: nil
+
 
   def equal_value?(left, right), do: RDF.Numeric.equal_value?(left, right)
 

lib/rdf/datatypes/integer.ex

@@ -58,6 +58,8 @@ defmodule RDF.Integer do
     end
   end
 
+  def cast(_), do: nil
+
 
   def equal_value?(left, right), do: RDF.Numeric.equal_value?(left, right)
 

lib/rdf/datatypes/lang_string.ex

@@ -53,8 +53,9 @@ defmodule RDF.LangString do
     end
   end
 
+
   def cast(_) do
-    raise "not supported"
+    nil
   end
 
 end

lib/rdf/datatypes/string.ex

@@ -91,4 +91,6 @@ defmodule RDF.String do
     end
   end
 
+  def cast(_), do: nil
+
 end

lib/rdf/datatypes/time.ex

@@ -141,4 +141,6 @@ defmodule RDF.Time do
     end
   end
 
+  def cast(_), do: nil
+
 end

test/unit/datatypes/boolean_test.exs

@@ -112,6 +112,10 @@ defmodule RDF.BooleanTest do
     test "with literals of unsupported datatypes" do
       assert RDF.DateTime.now() |> RDF.Boolean.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Boolean.cast(:foo) == nil
+    end
   end
 
 

test/unit/datatypes/date_test.exs

@@ -109,6 +109,10 @@ defmodule RDF.DateTest do
       assert RDF.integer(1) |> RDF.Date.cast() == nil
       assert RDF.decimal(3.14) |> RDF.Date.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Date.cast(:foo) == nil
+    end
   end
 
 end

test/unit/datatypes/date_time_test.exs

@@ -163,6 +163,10 @@ defmodule RDF.DateTimeTest do
       assert RDF.integer(1)    |> RDF.DateTime.cast() == nil
       assert RDF.decimal(3.14) |> RDF.DateTime.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.DateTime.cast(:foo) == nil
+    end
   end
 
 

test/unit/datatypes/decimal_test.exs

@@ -117,6 +117,10 @@ defmodule RDF.DecimalTest do
     test "with literals of unsupported datatypes" do
       assert RDF.DateTime.now() |> RDF.Decimal.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Decimal.cast(:foo) == nil
+    end
   end
 
 

test/unit/datatypes/double_test.exs

@@ -105,6 +105,10 @@ defmodule RDF.DoubleTest do
     test "with literals of unsupported datatypes" do
       assert RDF.DateTime.now() |> RDF.Double.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Double.cast(:foo) == nil
+    end
   end
 
 end

test/unit/datatypes/integer_test.exs

@@ -70,6 +70,10 @@ defmodule RDF.IntegerTest do
     test "with literals of unsupported datatypes" do
       assert RDF.DateTime.now() |> RDF.Integer.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Integer.cast(:foo) == nil
+    end
   end
 
 

test/unit/datatypes/string_test.exs

@@ -122,6 +122,10 @@ defmodule RDF.StringTest do
       assert RDF.decimal("NAN") |> RDF.String.cast() == nil
       assert RDF.double(true)   |> RDF.String.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.String.cast(:foo) == nil
+    end
   end
 
 end

test/unit/datatypes/time_test.exs

@@ -96,6 +96,10 @@ defmodule RDF.TimeTest do
       assert RDF.integer(1) |> RDF.Time.cast() == nil
       assert RDF.decimal(3.14) |> RDF.Time.cast() == nil
     end
+
+    test "with non-RDF terms" do
+      assert RDF.Time.cast(:foo) == nil
+    end
   end
 
 end