62 lines
1.8 KiB
Elixir
62 lines
1.8 KiB
Elixir
defmodule RDF.Serialization.Encoder do
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@moduledoc !"""
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A behaviour for encoders of RDF data structures in a specific `RDF.Serialization` format.
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"""
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@doc """
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Serializes a RDF data structure into a string.
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It should return an `{:ok, string}` tuple, with `string` being the serialized
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RDF data structure, or `{:error, reason}` if an error occurs.
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"""
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@callback encode(RDF.Data.t(), keyword) :: {:ok, String.t()} | {:error, any}
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@doc """
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Serializes a RDF data structure into a string.
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As opposed to `encode`, it raises an exception if an error occurs.
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Note: The `__using__` macro automatically provides an overridable default
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implementation based on the non-bang `encode` function.
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"""
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@callback encode!(RDF.Data.t(), keyword) :: String.t()
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@doc """
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Serializes a RDF data structure into a stream.
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It should return a stream emitting either strings or iodata of the
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serialized RDF data structure. If both forms are supported the form
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should be configurable via the `:mode` option.
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"""
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@callback stream(RDF.Data.t(), keyword) :: Enumerable.t()
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@optional_callbacks stream: 2
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defmacro __using__(_) do
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quote bind_quoted: [], unquote: true do
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@behaviour unquote(__MODULE__)
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@impl unquote(__MODULE__)
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@dialyzer {:nowarn_function, encode!: 2}
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@spec encode!(RDF.Data.t(), keyword) :: String.t()
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def encode!(data, opts \\ []) do
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case encode(data, opts) do
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{:ok, data} -> data
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{:error, reason} -> raise reason
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end
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end
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defoverridable unquote(__MODULE__)
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@before_compile unquote(__MODULE__)
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end
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end
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defmacro __before_compile__(_env) do
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quote do
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@stream_support __MODULE__ |> Module.definitions_in() |> Keyword.has_key?(:stream)
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@doc false
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def stream_support?, do: @stream_support
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end
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end
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end
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