rdf-ex/lib/rdf.ex
2017-06-18 23:04:58 +02:00

155 lines
5 KiB
Elixir

defmodule RDF do
@moduledoc """
The top-level module of RDF.ex.
RDF.ex consists of:
- modules for the nodes of an RDF graph
- URIs are (currently) represented via Elixirs `URI` struct and should be
constructed with `RDF.uri/1`
- `RDF.BlankNode`
- `RDF.Literal`
- a facility for the mapping of URIs of a vocabulary to Elixir modules and
functions: `RDF.Vocabulary.Namespace`
- modules for the construction of statements
- `RDF.Triple`
- `RDF.Quad`
- `RDF.Statement`
- modules for collections of statements
- `RDF.Description`
- `RDF.Graph`
- `RDF.Dataset`
- `RDF.Data`
- the foundations for the definition of RDF serialization formats
- `RDF.Serialization`
- `RDF.Serialization.Decoder`
- `RDF.Serialization.Encoder`
- and the implementation of two basic RDF serialization formats
- `RDF.NTriples`
- `RDF.NQuads`
This top-level module provides shortcut functions for the construction of the
basic elements and structures of RDF and some general helper functions.
For a general introduction you may refer to the [README](readme.html).
"""
alias RDF.{Namespace, Literal, BlankNode, Triple, Quad,
Description, Graph, Dataset}
@doc """
Checks if the given value is a RDF resource.
## Examples
iex> RDF.resource?(RDF.uri("http://example.com/resource"))
true
iex> RDF.resource?(EX.resource)
true
iex> RDF.resource?(RDF.bnode)
true
iex> RDF.resource?(42)
false
"""
def resource?(value)
def resource?(%URI{}), do: true
def resource?(atom) when is_atom(atom), do: resource?(Namespace.resolve_term(atom))
def resource?(%BlankNode{}), do: true
def resource?(_), do: false
@doc """
Checks if the given value is an URI.
## Examples
iex> RDF.uri?("http://www.example.com/foo")
true
iex> RDF.uri?("not a uri")
false
"""
def uri?(some_uri = %URI{}) do
# The following was suggested at http://stackoverflow.com/questions/30696761/check-if-a-url-is-valid-in-elixir
# TODO: Find a better way! Maybe <https://github.com/marcelog/ex_rfc3986>?
case some_uri do
%URI{scheme: nil} -> false
_uri -> true
end
end
def uri?(value) when is_binary(value), do: uri?(URI.parse(value))
def uri?(_), do: false
@doc """
Generator function for URIs from strings or term atoms of a `RDF.Namespace`.
This function is used for the `~I` sigil.
## Examples
iex> RDF.uri("http://www.example.com/foo")
%URI{authority: "www.example.com", fragment: nil, host: "www.example.com",
path: "/foo", port: 80, query: nil, scheme: "http", userinfo: nil}
iex> RDF.uri(RDF.NS.RDFS.Class)
%URI{authority: "www.w3.org", fragment: "Class", host: "www.w3.org",
path: "/2000/01/rdf-schema", port: 80, query: nil, scheme: "http",
userinfo: nil}
iex> RDF.uri("not a uri")
** (RDF.InvalidURIError) string "not a uri" is not a valid URI
"""
@spec uri(URI.t | binary | atom) :: URI.t
def uri(atom) when is_atom(atom), do: Namespace.resolve_term(atom)
def uri(string) do
with parsed_uri = URI.parse(string) do
if uri?(parsed_uri) do
parsed_uri
else
raise RDF.InvalidURIError, ~s(string "#{string}" is not a valid URI)
end
end
end
defdelegate bnode(), to: BlankNode, as: :new
defdelegate bnode(id), to: BlankNode, as: :new
defdelegate literal(value), to: Literal, as: :new
defdelegate literal(value, opts), to: Literal, as: :new
defdelegate triple(s, p, o), to: Triple, as: :new
defdelegate triple(tuple), to: Triple, as: :new
defdelegate quad(s, p, o, g), to: Quad, as: :new
defdelegate quad(tuple), to: Quad, as: :new
defdelegate description(arg), to: Description, as: :new
defdelegate description(arg1, arg2), to: Description, as: :new
defdelegate description(arg1, arg2, arg3), to: Description, as: :new
defdelegate graph(), to: Graph, as: :new
defdelegate graph(arg), to: Graph, as: :new
defdelegate graph(arg1, arg2), to: Graph, as: :new
defdelegate graph(arg1, arg2, arg3), to: Graph, as: :new
defdelegate graph(arg1, arg2, arg3, arg4), to: Graph, as: :new
defdelegate dataset(), to: Dataset, as: :new
defdelegate dataset(arg), to: Dataset, as: :new
defdelegate dataset(arg1, arg2), to: Dataset, as: :new
for term <- ~w[type subject predicate object first rest value]a do
defdelegate unquote(term)(), to: RDF.NS.RDF
defdelegate unquote(term)(s, o), to: RDF.NS.RDF
defdelegate unquote(term)(s, o1, o2), to: RDF.NS.RDF
defdelegate unquote(term)(s, o1, o2, o3), to: RDF.NS.RDF
defdelegate unquote(term)(s, o1, o2, o3, o4), to: RDF.NS.RDF
defdelegate unquote(term)(s, o1, o2, o3, o4, o5), to: RDF.NS.RDF
end
defdelegate langString(), to: RDF.NS.RDF
defdelegate unquote(nil)(), to: RDF.NS.RDF
end