Redland RDF Application Framework - OCaml Interface

Installing the Redland OCaml interface

This is built if --with-ocaml is given to the configure line, or --with-ocaml=ocamlfind to use a particular ocamlfind program. The standard 'make' at the top level will build it.

You can also compile the ocaml interface by hand as follows:

  cd ocaml
  make

  # optional - runs the tests
  make check

To install it system wide do this as root (or maybe via sudo make install):

  root# make install

The ocaml interface for Redland is experimental and requires OCaml 3.12 or newer. It has been tested with the following versions:

3.12 on OSX/x86
3.12 on Linux/x86

Testing the Redland OCaml interface

If you did the install above, run the ocaml example program with:

  ocamlfind ocamlopt -package camlrdf -o example.opt example.ml -linkpkg
  ./example.opt

and the result should be:

  found statement: {[http://www.dajobe.org/], [http://purl.org/dc/elements/1.1/creator], "Dave Beckett"}
  Parsing URI (file) ../data/dc.rdf
  Parsing added 3 statements
  Printing all statements
  Statement: {[http://www.dajobe.org/], [http://purl.org/dc/elements/1.1/description], "The generic home page of Dave Beckett."}
  Statement: {[http://www.dajobe.org/], [http://purl.org/dc/elements/1.1/title], "Dave Beckett's Home Page"}
  Statement: {[http://www.dajobe.org/], [http://purl.org/dc/elements/1.1/creator], "Dave Beckett"}
  Statement: {[http://www.dajobe.org/], [http://purl.org/dc/elements/1.1/creator], "Dave Beckett"}
  querying for dc:titles:
  {
    a = http://www.dajobe.org/ (RESOURCE)
    c = Dave Beckett's Home Page (LITERAL)
  }
  Writing model to test-out.rdf as rdf/xml

Using the Redland OCaml API

Read the pydoc Redland OCaml API for full details of the classes and methods provided along with examples of use.

The OCaml API is an object-based API reflecting the same structure of the Redland objects with simple mappings between them:

Concept	Redland Class	OCaml Module	Purpose
Resource / Literal	librdf_node	`Rdf.Node`	RDF Model & Syntax nodes
Statement / Triple	librdf_statement	`Rdf.Statement`	RDF Model & Syntax arcs (statements, triples) [isa Resource]
Model	librdf_model	`Rdf.Model`	Set of Statement s usually held in one Storage
Storage	librdf_storage	`Rdf.Storage`	Storage for Model s either persistant or in-memory
Stream	librdf_stream	`Rdf.Stream`	Providing sequences of Statement s from Parser s, queries
Parser	librdf_parser	`Rdf.Parser`	Parsing to deliver Stream of Statement s or writing to a Model
Query	librdf_query	`Rdf.Query`	Querying a Model to deliver QueryResults
QueryResults	librdf_query_results	`Rdf.QueryResults`	Results of applying a Query to a Model giving either variable bindings with Node values or Stream of Statement s
Serializer	librdf_serializer	`Rdf.Serializer`	Serializing a Model in a format such as RDF/XML
Iterator	librdf_iterator	`Rdf.Iterator`	Enumerating Node s from queries.
URI	librdf_uri	`Rdf.Uri`	Providing URIs for Resource s, Parser s, ...
World	librdf_world		RDF wrapper class handling Redland startup/shutdown
Digest	librdf_digest		Internal content digest class
Hash	librdf_hash		Internal key:value maps class