Add RDF.Dataset.graph_count/1

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](http://semver.org/) and
 ### Added
 
 - support for `RDF.PropertyMap` on `RDF.Statement.new/2` and `RDF.Statement.coerce/2`
+- `RDF.Dataset.graph_count/1`
 
 ### Changed
 

lib/rdf/dataset.ex

@@ -532,6 +532,24 @@ defmodule RDF.Dataset do
     end
   end
 
+  @doc """
+  The number of graphs within a `RDF.Dataset`.
+
+  ## Examples
+
+      iex> RDF.Dataset.new([
+      ...>   {EX.S1, EX.p1, EX.O1},
+      ...>   {EX.S2, EX.p2, EX.O2},
+      ...>   {EX.S1, EX.p2, EX.O3, EX.Graph}])
+      ...> |> RDF.Dataset.graph_count()
+      2
+
+  """
+  @spec graph_count(t) :: non_neg_integer
+  def graph_count(%__MODULE__{} = dataset) do
+    Enum.count(dataset.graphs)
+  end
+
   @doc """
   The number of statements within a `RDF.Dataset`.