rdf-ex/lib/rdf/serializations/nquads_encoder.ex
2020-09-28 11:09:35 +02:00

36 lines
1,009 B
Elixir

defmodule RDF.NQuads.Encoder do
@moduledoc false
use RDF.Serialization.Encoder
alias RDF.{Dataset, Graph, Statement}
@impl RDF.Serialization.Encoder
@callback encode(Graph.t() | Dataset.t(), keyword | map) :: {:ok, String.t()} | {:error, any}
def encode(data, _opts \\ []) do
result =
data
|> Enum.reduce([], fn statement, result -> [statement(statement) | result] end)
|> Enum.reverse()
|> Enum.join("\n")
{:ok, if(result == "", do: result, else: "#{result}\n")}
end
@spec statement(Statement.t()) :: String.t()
def statement(statement)
def statement({subject, predicate, object, nil}) do
statement({subject, predicate, object})
end
def statement({subject, predicate, object, graph}) do
"#{term(subject)} #{term(predicate)} #{term(object)} #{term(graph)} ."
end
def statement({subject, predicate, object}) do
"#{term(subject)} #{term(predicate)} #{term(object)} ."
end
defdelegate term(value), to: RDF.NTriples.Encoder
end