defmodule RDF.PrefixMap do
@moduledoc """
A mapping a prefix atoms to IRI namespaces.
The empty prefix is represented as the `:""` atom.
`RDF.PrefixMap` implements the `Enumerable` protocol.
"""
alias RDF.IRI
@type prefix :: atom
@type namespace :: IRI.t()
@type coercible_prefix :: atom | String.t()
@type coercible_namespace :: RDF.Vocabulary.Namespace.t() | String.t() | IRI.t()
@type prefix_map :: %{prefix => namespace}
@type conflict_resolver ::
(coercible_prefix, coercible_namespace, coercible_namespace -> coercible_namespace)
| :ignore
| :overwrite
@type t :: %__MODULE__{
map: prefix_map
}
defstruct map: %{}
@doc """
Creates an empty `RDF.PrefixMap`.
"""
@spec new :: t
def new, do: %__MODULE__{}
@doc """
Creates a new `RDF.PrefixMap` with initial mappings.
The initial prefix mappings can be passed as keyword lists or maps.
The keys for the prefixes can be given as atoms or strings and will be normalized to atoms.
The namespaces can be given as `RDF.IRI`s or strings and will be normalized to `RDF.IRI`s.
"""
@spec new(t | map | keyword) :: t
def new(map)
def new(%__MODULE__{} = prefix_map), do: prefix_map
def new(map) when is_map(map) do
%__MODULE__{map: Map.new(map, &normalize/1)}
end
def new(map) when is_list(map) do
map |> Map.new() |> new()
end
defp normalize({prefix, namespace}) when is_atom(prefix),
do: {prefix, IRI.coerce_base(namespace)}
defp normalize({prefix, namespace}) when is_binary(prefix),
do: normalize({String.to_atom(prefix), namespace})
defp normalize({prefix, namespace}),
do:
raise(ArgumentError, "Invalid prefix mapping: #{inspect(prefix)} => #{inspect(namespace)}")
@doc """
Adds a prefix mapping to `prefix_map`.
Unless a mapping of `prefix` to a different namespace already exists,
an `:ok` tuple is returned, otherwise an `:error` tuple.
"""
@spec add(t, coercible_prefix, coercible_namespace) :: {:ok, t} | {:error, String.t()}
def add(prefix_map, prefix, namespace)
def add(%__MODULE__{map: map}, prefix, %IRI{} = namespace) when is_atom(prefix) do
if conflicts?(map, prefix, namespace) do
{:error, "prefix #{inspect(prefix)} is already mapped to another namespace"}
else
{:ok, %__MODULE__{map: Map.put(map, prefix, namespace)}}
end
end
def add(%__MODULE__{} = prefix_map, prefix, namespace) do
{prefix, namespace} = normalize({prefix, namespace})
add(prefix_map, prefix, namespace)
end
@doc """
Adds a prefix mapping to the given `RDF.PrefixMap` and raises an exception in error cases.
"""
@spec add!(t, coercible_prefix, coercible_namespace) :: t
def add!(prefix_map, prefix, namespace) do
case add(prefix_map, prefix, namespace) do
{:ok, new_prefix_map} -> new_prefix_map
{:error, error} -> raise error
end
end
@doc """
Adds a prefix mapping to `prefix_map` overwriting an existing mapping.
"""
@spec put(t, coercible_prefix, coercible_namespace) :: t
def put(prefix_map, prefix, namespace)
def put(%__MODULE__{map: map}, prefix, %IRI{} = namespace) when is_atom(prefix) do
%__MODULE__{map: Map.put(map, prefix, namespace)}
end
def put(%__MODULE__{} = prefix_map, prefix, namespace) do
{prefix, namespace} = normalize({prefix, namespace})
put(prefix_map, prefix, namespace)
end
@doc """
Merges two `RDF.PrefixMap`s.
The second prefix map can also be given as any structure which can converted
to a `RDF.PrefixMap` via `new/1`.
If the prefix maps can be merged without conflicts, that is there are no
prefixes mapped to different namespaces an `:ok` tuple is returned.
Otherwise an `:error` tuple with the list of prefixes with conflicting
namespaces is returned.
See also `merge/3` which allows you to resolve conflicts with a function.
"""
@spec merge(t, t | map | keyword) :: {:ok, t} | {:error, [atom | String.t()]}
def merge(prefix_map1, prefix_map2)
def merge(%__MODULE__{map: map1}, %__MODULE__{map: map2}) do
case merge_conflicts(map1, map2) do
[] -> {:ok, %__MODULE__{map: Map.merge(map1, map2)}}
conflicts -> {:error, conflicts}
end
end
def merge(%__MODULE__{} = prefix_map, other_prefixes) do
merge(prefix_map, new(other_prefixes))
rescue
FunctionClauseError ->
# credo:disable-for-next-line Credo.Check.Warning.RaiseInsideRescue
raise ArgumentError, "#{inspect(other_prefixes)} is not convertible to a RDF.PrefixMap"
end
@doc """
Merges two `RDF.PrefixMap`s, resolving conflicts through the given `conflict_resolver` function.
The second prefix map can also be given as any structure which can converted
to a `RDF.PrefixMap` via `new/1`.
The given function will be invoked when there are conflicting mappings of
prefixes to different namespaces; its arguments are `prefix`, `namespace1`
(the namespace for the prefix in the first prefix map),
and `namespace2` (the namespace for the prefix in the second prefix map).
The value returned by the `conflict_resolver` function is used as the namespace
for the prefix in the resulting prefix map.
Non-`RDF.IRI` values will be tried to be converted to `RDF.IRI`s via
`RDF.IRI.new` implicitly.
The most common conflict resolution strategies on can be chosen directly with
the following atoms:
- `:ignore`: keep the original namespace from `prefix_map1`
- `:overwrite`: use the other namespace from `prefix_map2`
If a conflict can't be resolved, the provided function can return `nil`.
This will result in an overall return of an `:error` tuple with the list of
prefixes for which the conflict couldn't be resolved.
If everything could be merged, an `:ok` tuple is returned.
"""
@spec merge(t, t | map | keyword, conflict_resolver | nil) ::
{:ok, t} | {:error, [atom | String.t()]}
def merge(prefix_map1, prefix_map2, conflict_resolver)
def merge(prefix_map1, prefix_map2, :ignore) do
merge(prefix_map1, prefix_map2, fn _, ns, _ -> ns end)
end
def merge(prefix_map1, prefix_map2, :overwrite) do
merge(prefix_map1, prefix_map2, fn _, _, ns -> ns end)
end
def merge(%__MODULE__{map: map1}, %__MODULE__{map: map2}, conflict_resolver)
when is_function(conflict_resolver) do
conflict_resolution = fn prefix, namespace1, namespace2 ->
case conflict_resolver.(prefix, namespace1, namespace2) do
nil -> :conflict
result -> IRI.new(result)
end
end
resolved_merge = Map.merge(map1, map2, conflict_resolution)
case resolved_merge_rest_conflicts(resolved_merge) do
[] -> {:ok, %__MODULE__{map: resolved_merge}}
conflicts -> {:error, conflicts}
end
end
def merge(%__MODULE__{} = prefix_map1, prefix_map2, conflict_resolver)
when is_function(conflict_resolver) do
merge(prefix_map1, new(prefix_map2), conflict_resolver)
end
def merge(prefix_map1, prefix_map2, nil), do: merge(prefix_map1, prefix_map2)
defp resolved_merge_rest_conflicts(map) do
Enum.reduce(map, [], fn
{prefix, :conflict}, conflicts -> [prefix | conflicts]
_, conflicts -> conflicts
end)
end
defp merge_conflicts(map1, map2) do
Enum.reduce(map1, [], fn {prefix, namespace}, conflicts ->
if conflicts?(map2, prefix, namespace) do
[prefix | conflicts]
else
conflicts
end
end)
end
defp conflicts?(map, prefix, namespace) do
(existing_namespace = Map.get(map, prefix)) && existing_namespace != namespace
end
@doc """
Merges two `RDF.PrefixMap`s and raises an exception in error cases.
See `merge/2` and `merge/3` for more information on merging prefix maps.
"""
@spec merge!(t, t | map | keyword, conflict_resolver | nil) :: t
def merge!(prefix_map1, prefix_map2, conflict_resolver \\ nil) do
case merge(prefix_map1, prefix_map2, conflict_resolver) do
{:ok, new_prefix_map} ->
new_prefix_map
{:error, conflicts} ->
raise "conflicting prefix mappings: #{Enum.map_join(conflicts, ", ", &inspect/1)}"
end
end
@doc """
Deletes the prefix mapping for `prefix` from `prefix_map`.
If no mapping for `prefix` exists, `prefix_map` is returned unchanged.
"""
@spec delete(t, coercible_prefix) :: t
def delete(prefix_map, prefix)
def delete(%__MODULE__{map: map}, prefix) when is_atom(prefix) do
%__MODULE__{map: Map.delete(map, prefix)}
end
def delete(prefix_map, prefix) when is_binary(prefix) do
delete(prefix_map, String.to_atom(prefix))
end
@doc """
Drops the given `prefixes` from `prefix_map`.
If `prefixes` contains prefixes that are not in `prefix_map`, they're simply ignored.
"""
@spec drop(t, [coercible_prefix]) :: t
def drop(prefix_map, prefixes)
def drop(%__MODULE__{map: map}, prefixes) do
%__MODULE__{
map:
Map.drop(
map,
Enum.map(prefixes, fn
prefix when is_binary(prefix) -> String.to_atom(prefix)
other -> other
end)
)
}
end
@doc """
Returns the namespace for the given `prefix` in `prefix_map`.
Returns `nil`, when the given `prefix` is not present in `prefix_map`.
"""
@spec namespace(t, coercible_prefix) :: namespace | nil
def namespace(prefix_map, prefix)
def namespace(%__MODULE__{map: map}, prefix) when is_atom(prefix) do
Map.get(map, prefix)
end
def namespace(prefix_map, prefix) when is_binary(prefix) do
namespace(prefix_map, String.to_atom(prefix))
end
@doc """
Returns the prefix for the given `namespace` in `prefix_map`.
Returns `nil`, when the given `namespace` is not present in `prefix_map`.
"""
@spec prefix(t, coercible_namespace) :: coercible_prefix | nil
def prefix(prefix_map, namespace)
def prefix(%__MODULE__{map: map}, %IRI{} = namespace) do
Enum.find_value(map, fn {prefix, ns} -> ns == namespace && prefix end)
end
def prefix(prefix_map, namespace) when is_binary(namespace) do
prefix(prefix_map, IRI.new(namespace))
end
@doc """
Returns whether the given prefix exists in the given `RDF.PrefixMap`.
"""
@spec has_prefix?(t, coercible_prefix) :: boolean
def has_prefix?(prefix_map, prefix)
def has_prefix?(%__MODULE__{map: map}, prefix) when is_atom(prefix) do
Map.has_key?(map, prefix)
end
def has_prefix?(prefix_map, prefix) when is_binary(prefix) do
has_prefix?(prefix_map, String.to_atom(prefix))
end
@doc """
Returns all prefixes from the given `RDF.PrefixMap`.
"""
@spec prefixes(t) :: [coercible_prefix]
def prefixes(%__MODULE__{map: map}) do
Map.keys(map)
end
@doc """
Returns all namespaces from the given `RDF.PrefixMap`.
"""
@spec namespaces(t) :: [coercible_namespace]
def namespaces(%__MODULE__{map: map}) do
Map.values(map)
end
@doc """
Converts an IRI into a prefixed name.
Returns `nil` when no prefix for the namespace of `iri` is defined in `prefix_map`.
## Examples
iex> RDF.PrefixMap.new(ex: "http://example.com/")
...> |> RDF.PrefixMap.prefixed_name(~I<http://example.com/Foo>)
"ex:Foo"
iex> RDF.PrefixMap.new(ex: "http://example.com/")
...> |> RDF.PrefixMap.prefixed_name("http://example.com/Foo")
"ex:Foo"
"""
@spec prefixed_name(t, IRI.t() | String.t()) :: String.t() | nil
def prefixed_name(prefix_map, iri)
def prefixed_name(%__MODULE__{} = prefix_map, %IRI{} = iri) do
prefixed_name(prefix_map, IRI.to_string(iri))
end
def prefixed_name(%__MODULE__{} = prefix_map, iri) when is_binary(iri) do
case prefix_name_pair(prefix_map, iri) do
{prefix, name} -> prefix <> ":" <> name
_ -> nil
end
end
@doc false
@spec prefix_name_pair(t, IRI.t() | String.t()) :: {String.t(), String.t()} | nil
def prefix_name_pair(prefix_map, iri)
def prefix_name_pair(%__MODULE__{} = prefix_map, %IRI{} = iri) do
prefix_name_pair(prefix_map, IRI.to_string(iri))
end
def prefix_name_pair(%__MODULE__{} = prefix_map, iri) when is_binary(iri) do
Enum.find_value(prefix_map, fn {prefix, namespace} ->
case String.trim_leading(iri, IRI.to_string(namespace)) do
^iri ->
nil
truncated_name ->
unless String.contains?(truncated_name, ~w[/ #]) do
{to_string(prefix), truncated_name}
end
end
end)
end
@doc """
Converts a prefixed name into an IRI.
Returns `nil` when the prefix in `prefixed_name` is not defined in `prefix_map`.
## Examples
iex> RDF.PrefixMap.new(ex: "http://example.com/")
...> |> RDF.PrefixMap.prefixed_name_to_iri("ex:Foo")
~I<http://example.com/Foo>
"""
@spec prefixed_name_to_iri(t, String.t()) :: IRI.t() | nil
def prefixed_name_to_iri(%__MODULE__{} = prefix_map, prefixed_name)
when is_binary(prefixed_name) do
case String.split(prefixed_name, ":", parts: 2) do
[prefix, name] ->
if ns = namespace(prefix_map, prefix) do
RDF.iri(ns.value <> name)
end
_ ->
nil
end
end
@doc """
Converts prefix map to a list.
Each prefix-namespace pair in the prefix map is converted to a two-element tuple
`{prefix, namespace_iri}` in the resulting list.
## Examples
iex> RDF.PrefixMap.new(ex: "http://example.com/") |> RDF.PrefixMap.to_list()
[ex: ~I<http://example.com/>]
"""
@spec to_list(t()) :: [{prefix(), namespace()}]
def to_list(%__MODULE__{map: map}), do: Map.to_list(map)
defimpl Enumerable do
def reduce(%RDF.PrefixMap{map: map}, acc, fun), do: Enumerable.reduce(map, acc, fun)
def member?(%RDF.PrefixMap{map: map}, mapping), do: Enumerable.member?(map, mapping)
def count(%RDF.PrefixMap{map: map}), do: Enumerable.count(map)
if Version.match?(System.version(), ">= 1.14.0") do
def slice(%RDF.PrefixMap{map: map}) do
size = map_size(map)
{:ok, size, &RDF.PrefixMap.to_list/1}
end
else
def slice(%RDF.PrefixMap{map: map}), do: Enumerable.slice(map)
end
end
defimpl Inspect do
import Inspect.Algebra
def inspect(prefix_map, opts) do
map = Map.to_list(prefix_map.map)
open = color("RDF.PrefixMap.new(%{", :map, opts)
sep = color(",", :map, opts)
close = color("})", :map, opts)
container_doc(open, map, close, opts, &to_map(&1, &2, color(" => ", :map, opts)),
separator: sep,
break: :strict
)
end
defp to_map({key, value}, opts, sep) do
concat(concat(to_doc(key, opts), sep), to_doc(value, opts))
end
end
end
