48 lines
1.3 KiB
Elixir
48 lines
1.3 KiB
Elixir
defmodule RDF.NTriples.Encoder do
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@moduledoc false
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use RDF.Serialization.Encoder
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alias RDF.{BlankNode, Dataset, Graph, IRI, XSD, Literal, Statement, Triple, LangString}
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@impl RDF.Serialization.Encoder
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@callback encode(Graph.t() | Dataset.t(), keyword | map) :: {:ok, String.t()} | {:error, any}
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def encode(data, _opts \\ []) do
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result =
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data
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|> Enum.reduce([], fn statement, result ->
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[statement(statement) | result]
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end)
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|> Enum.reverse()
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|> Enum.join("\n")
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{:ok, if(result == "", do: result, else: result <> "\n")}
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end
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@spec statement(Triple.t()) :: String.t()
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def statement({subject, predicate, object}) do
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"#{term(subject)} #{term(predicate)} #{term(object)} ."
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end
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@spec term(Statement.subject() | Statement.predicate() | Statement.object()) :: String.t()
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def term(%IRI{} = iri) do
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"<#{to_string(iri)}>"
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end
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def term(%Literal{literal: %LangString{} = lang_string}) do
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~s["#{lang_string.value}"@#{lang_string.language}]
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end
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def term(%Literal{literal: %XSD.String{} = xsd_string}) do
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~s["#{xsd_string.value}"]
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end
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def term(%Literal{} = literal) do
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~s["#{Literal.lexical(literal)}"^^<#{to_string(Literal.datatype_id(literal))}>]
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end
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def term(%BlankNode{} = bnode) do
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to_string(bnode)
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end
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end
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