rdf-ex/lib/rdf/serializations/ntriples_decoder.ex
2020-03-10 01:37:53 +01:00

33 lines
1.1 KiB
Elixir

defmodule RDF.NTriples.Decoder do
@moduledoc false
use RDF.Serialization.Decoder
import RDF.Serialization.ParseHelper, only: [error_description: 1]
alias RDF.{Dataset, Graph}
@impl RDF.Serialization.Decoder
@spec decode(String.t, keyword | map) :: {:ok, Graph.t | Dataset.t} | {:error, any}
def decode(content, _opts \\ []) do
with {:ok, tokens, _} <- tokenize(content),
{:ok, ast} <- parse(tokens) do
{:ok, build_graph(ast)}
else
{:error, {error_line, :ntriples_lexer, error_descriptor}, _error_line_again} ->
{:error, "N-Triple scanner error on line #{error_line}: #{error_description error_descriptor}"}
{:error, {error_line, :ntriples_parser, error_descriptor}} ->
{:error, "N-Triple parser error on line #{error_line}: #{error_description error_descriptor}"}
end
end
defp tokenize(content), do: content |> to_charlist |> :ntriples_lexer.string
defp parse(tokens), do: tokens |> :ntriples_parser.parse
defp build_graph(ast) do
Enum.reduce ast, RDF.Graph.new, fn(triple, graph) ->
RDF.Graph.add(graph, triple)
end
end
end