ont-app/igraph-vocabulary

Support for creating keyword identifiers (KWIs) in IGraph-compliant graphs and aligning data in IGraph graphs to data in other formats.

Contents

• Dependencies
• Overview
• The mint-kwi method
• The resolve-namespace-prefixes function
• Supporting ontology
  • Default subsumed-by declarations
• License

Dependencies

Available at Clojars.

Require thus:

(ns ont-app.igraph-vocabulary.core-test
(:require 
  [
   [ont-app.igraph.core :as igraph]
   [ont-app.vocabulary.core :as voc]
   [ont-app.igraph-vocabulary.core :as igv]
   ))

Overview

ont-app/igraph and ont-app/vocabulary are independent libraries. The former defining a generic graph-based primitive container, and the latter defining a way of treating namespaced Keyword Identifies (KWIs) as though they were URIs comprising a public vocabulary, aligned to RDF namespaces. ont-app/igraph-vocabulary is responsible for basic functionality involving the intersection or these two, providing some basic ontological constructs that express common features of IGraph implementations.

For purposes of this discussion, the term URI and IRI will be used interchangably. In practice clojure keywords are encoded as UTF-8, making them IRIs. The term URI has a much greater mind-share, to the extent that any of this stuff has mind-share at all.

A KWI is a qualified clojure keyword used exactly the way a URI is used in RDF. Ideally URIs should be importable as KWIs and integrated into IGraph-based models, and conversely KWIs should be exportable as standard RDF-type URIs.

Since this is the lowest level at which both igraph and vocabulary are in play. This is the level that defines a small supporting ontology igraph-based graphs.

The mint-kwi method

When building a model in a graph representation, it's a common occurrence to need to create canonically named KWIs on the fly, especially to identify newly encountered instances of some class of entities. For example :employee/123, mappable to http://rdf.mycompany.com/employee#123.

The mint-kwi method returns a keyword identifier based on a head keyword (which typically names a class) and any number of other arguments (typically a set of predicate/value pairs). The method is dispatched on the head.

Best practice is to provide as many predicate/value pairs as are necessary to uniquely distinguish the thing being identified within whatever universe you're playing in.

Let's assume the following namespace declaration (note the metadata in the ns):

(ns ont-app.igraph-vocabulary.core-test
  {:vann/preferredNamespacePrefix "eg"
   :vann/preferredNamespaceUri "http://example.com/"
   }
 (require
 [ont-app.igraph.core :as igraph]
 [ont-app.igraph-vocabulary.core :as igv :refer [mint-kwi]]
 [ont-app.vocabulary.core :as voc]
 ))

The default method will simply concatenate the names of the keywords provided:

> (mint-kwi :eg/Example :eg/number 1)
:eg/Example_number_1
>

Since we have the proper metadata declared for core-test module, we can get RDF equivalents:

> (voc/qname-for :eg/Example_number_1)
"eg:Example_number_1"
>
> (voc/uri-for :eg/Example_number_1)
"http://example.com/Example_number_1"
> 

We can write a custom method dispatched on the head:

> (defmethod mint-kwi :eg/Example
    [head & {:keys [:eg/number]}]
    (keyword (namespace head)
      (str (name head)
         "_"
         number)))
#multifn[mint-kwi 0x535c5c20]
> (mint-kwi :eg/Example :eg/number 2)
:eg/Example_2
> 

The resolve-namespace-prefixes function

It may be the case that you are referencing a graph whose URIs may be in need of translating into KWIs. In such cases, you can apply this function as a reduce-spo:

> (def g (igraph/reduce-spo resove-namespace-prefixes g))

This will reset the value of igraph g with its URIs translated into their equivalent KWIs, wherever the appropriate namespace metadata has been supplied.

Supporting ontology

These declarations are defined as the constant igv/ontology, an instance of the simple IGraph implementation ont-app.igraph.graph/Graph.

The igraph namespace.

This dedicated to naming constructs pertinent to implementations of IGraph.

(voc/put-ns-meta!
 'ont-app.igraph.core
 {
  :vann/preferredNamespacePrefix "igraph"
  :vann/preferredNamespaceUri "http://rdf.naturallexicon.org/ont-app/igraph/ont#"
  }
 )

KWI (:igraph/*)	type	description
CompiledObject	Class	A graph element compiled in the native execution environment, typically a function, a graph, or a vector. This is platform-specific. The intent here is to facilitate inter-operation with other platforms, e.g. python, using a shared ontology.
Function	CompiledObject	A compiled object executable in the native execution environment as a pure function
Vector	CompiledObject	A compiled container holding an integer-indexed sequence
Graph	CompiledObject	An compiled implementation of IGraph
projectedRange	property	"p projectedRange obj" asserts that the property p will have obj in its range, where obj is a subclass of CompiledObject. As a compiled object, obj is neither a class nor a literal.
compiledAs	property	"kwi compiledAs obj" asserts that an entity identified across platforms as kwi (or its equivalent URI) is implemented in the current exectuion environment as CompiledObject obj
subsumedBy	property	"x subsumedBy y" asserts a subsumption relationship between x and y. This may be used in Clojure to derive/underive values to use in method dispatch, for example.

Default subsumedBy declarations

The following subsumedBy declarations are defined in ont-app.igraph-vocabulary.ont.cljc:

  [:rdf/type :rdfs/subPropertyOf :igraph/subsumedBy]
  [:rdfs/subClassOf :rdfs/subPropertyOf :igraph/subsumedBy]
  [:rdfs/subPropertyOf :rdfs/subPropertyOf :igraph/subsumedBy]

License

Copyright © 2019-20 Eric D. Scott

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.

Natural Lexicon logo - Copyright © 2020 Eric D. Scott. Artwork by Athena M. Scott. Released under Creative Commons Attribution-ShareAlike 4.0 International license. Under the terms of this license, if you display this logo or derivates thereof, you must include an attribution to the original source, with a link to https://github.com/ont-app, or http://ericdscott.com.