Beaver is a semantic programming language. It accepts and manipulates data in the form of RDF graphs.

To install, navigate to the source directory and run python setup.py install.

Beaver is an interpreted superset of the Turtle RDF serialization format. Therefore, any valid Turtle file is also valid Beaver code. RDF/XML can also be parsed using the @load command (requires librdf, the Redland RDF library Python bindings: http://librdf.org/docs/python.html).

RDF is a "data description language"; Beaver is a Turing-complete programming language that can be used to express semantic relationships between objects. Therefore, regular, well-defined graphs and graphs with recursive structure can often be represented more tersely in Beaver than in standard RDF serialization formats.

Examples of Beaver commands:

# open another Beaver or Turtle file (local or online) and parse the 
# results into the current graph
@import <data_file.ttl>

# load RDF/XML file
@load <http://www.nexml.org/nexml/examples/trees.rdf>

# define and call functions
?create_edge ?child ?parent ?edge = {
    ?child <part_of_edge> ?edge .
    ?parent <part_of_edge> ?edge .
    ?edge <has_parent> ?parent ;
          <has_child> ?child .
}

?create_edge <node1> <node2> <edge1> .
?create_edge <node2> <node3> <edge2> .

# loop over items in a collection
@for ?node in (<a> <b> <c> <d> <e>) {
    ?node a <thing> .
}

# save the current graph as an image file
@draw <test.png>
@draw <test2.jpg>

# remove triples from the graph
@del <node1> <part_of_edge> <edge1> .

# output the current graph to screen
@out

# save the current graph as Turtle
@out <output.ttl>

Using the interpreter, you can save images of the resulting graphs (requires graphviz and either pydot or pygraphviz.) For example:

beaver -d test.png -e "<ben> a <human> ; <likes> <carol>, <football> . <carol> a <human> ; <likes> <ben>, <anime> . <ruben> a <human>, <baby> ."

Beaver is written in Python and can also be used as a Python library, e.g.:

from beaver import Graph

graph = Graph()
graph.parse(text='''
    ?great ?thing = { ?thing <is> <great> }
    ?great <beaver>
''')

graph.draw('output.png')