rdf-ex/lib/rdf/property_map.ex

145 lines
3.8 KiB
Elixir

defmodule RDF.PropertyMap do
defstruct iris: %{},
terms: %{}
alias RDF.IRI
@type t :: %__MODULE__{
iris: %{atom => IRI.t()},
terms: %{IRI.t() => atom}
}
@behaviour Access
def new(), do: %__MODULE__{}
def new(%__MODULE__{} = initial), do: initial
def new(initial) do
{:ok, property_map} = new() |> add(initial)
property_map
end
def iri(%__MODULE__{} = property_map, term) do
Map.get(property_map.iris, coerce_term(term))
end
def term(%__MODULE__{} = property_map, iri) do
Map.get(property_map.terms, IRI.new(iri))
end
def iri_defined?(%__MODULE__{} = property_map, term) do
Map.has_key?(property_map.iris, coerce_term(term))
end
def term_defined?(%__MODULE__{} = property_map, iri) do
Map.has_key?(property_map.terms, IRI.new(iri))
end
@impl Access
def fetch(%__MODULE__{} = property_map, term) do
Access.fetch(property_map.iris, coerce_term(term))
end
def add(%__MODULE__{} = property_map, term, iri) do
do_set(property_map, :add, coerce_term(term), IRI.new(iri))
end
def add(%__MODULE__{} = property_map, mappings) do
Enum.reduce_while(mappings, {:ok, property_map}, fn {term, iri}, {:ok, property_map} ->
with {:ok, property_map} <- add(property_map, term, iri) do
{:cont, {:ok, property_map}}
else
error -> {:halt, error}
end
end)
end
def put(%__MODULE__{} = property_map, term, iri) do
{:ok, added} = do_set(property_map, :put, coerce_term(term), IRI.new(iri))
added
end
def put(%__MODULE__{} = property_map, mappings) do
Enum.reduce(mappings, property_map, fn {term, iri}, property_map ->
put(property_map, term, iri)
end)
end
defp do_set(property_map, op, term, iri) do
do_set(property_map, op, term, iri, Map.get(property_map.iris, term))
end
defp do_set(property_map, _, _, iri, iri), do: {:ok, property_map}
defp do_set(property_map, _, term, iri, nil) do
{:ok,
%__MODULE__{
property_map
| iris: Map.put(property_map.iris, term, iri),
terms: Map.put(property_map.terms, iri, term)
}}
end
defp do_set(_context, :add, term, new_iri, old_iri) do
{:error, "conflicting mapping for #{term}: #{new_iri}; already mapped to #{old_iri}"}
end
defp do_set(property_map, :put, term, new_iri, old_iri) do
%__MODULE__{property_map | terms: Map.delete(property_map.terms, old_iri)}
|> do_set(:put, term, new_iri, nil)
end
def delete(%__MODULE__{} = property_map, term) do
term = coerce_term(term)
if iri = Map.get(property_map.iris, term) do
%__MODULE__{
property_map
| iris: Map.delete(property_map.iris, term),
terms: Map.delete(property_map.terms, iri)
}
else
property_map
end
end
def drop(%__MODULE__{} = property_map, terms) when is_list(terms) do
Enum.reduce(terms, property_map, fn term, property_map ->
delete(property_map, term)
end)
end
defp coerce_term(term) when is_atom(term), do: term
defp coerce_term(term) when is_binary(term), do: String.to_atom(term)
@impl Access
def pop(%__MODULE__{} = property_map, term) do
case Access.pop(property_map.iris, coerce_term(term)) do
{nil, _} ->
{nil, property_map}
{iri, new_context_map} ->
{iri, %__MODULE__{iris: new_context_map}}
end
end
@impl Access
def get_and_update(property_map, term, fun) do
term = coerce_term(term)
current = iri(property_map, term)
case fun.(current) do
{old_iri, new_iri} ->
{:ok, property_map} = do_set(property_map, :put, term, IRI.new(new_iri), IRI.new(old_iri))
{old_iri, property_map}
:pop ->
{current, delete(property_map, term)}
other ->
raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
end
end
end