The cl-ntriples Reference Manual

Table of Contents

The cl-ntriples Reference Manual

This is the cl-ntriples Reference Manual, version 2012.12.16, generated automatically by Declt version 2.4 "Will Decker" on Wed Jun 20 11:16:36 2018 GMT+0.

1 Introduction

CL-NTRIPLES provides a simple parser for the N-Triples data format as defined by the W3C for storing RDF/Semantic information. N-Triples is a line-based, plain text format for encoding an RDF graph.

Main entry function is PARSE-NT method that parses N-Triples from the given source. This method accepts a file pathname, an input stream, or a string.

Returns a list of triples consisting of three elements: subject, predicate, object. Subjects can be either an uriref or a nodeID. Objects can be of three types: uriref, nodeID or a literal. Depending on the type of the object it is encoded into an association list.

N-Triples data format standard definition is provided in the W3C documents:

• RDF Testcases, N-Triples

Check also the Semantic Web page on CLiki.

Project page on Sourceforge.

Sample usage

CL-NTRIPLES is available through Quicklisp:

(ql:quickload :cl-ntriples)

CL-NTRIPLES was developed for a practical purpose of accessing the wealth of data accumulated by the DBPedia project. For example, let's query information about a Ukrainian city of Chernihiv (wiki, dbpedia):

(defvar page-url "http://dbpedia.org/data/Chernihiv.ntriples")
(defvar *res* (nt:parse-nt (drakma:http-request page-url)))
;; *res* now contains a list of triples, let's query some predicates
;; for brevity, predicates will defined as variables

(defconstant +prop-area-total-km+ "http://dbpedia.org/property/areaTotalKm")
(defconstant +rdf-label+ "http://www.w3.org/2000/01/rdf-schema#label")

;; querying predicates is now reduced to a simple function call:
;; nt:predicate? TRIPLES PREDICATE &key LANG DATA-TYPE

;; what is the city area in km2?
(nt:predicate? *res* +prop-area-total-km+)
=> (("http://dbpedia.org/resource/Chernihiv"
  "http://dbpedia.org/property/areaTotalKm"
  ((:LITERAL-STRING . "79")
   (:URIREF . "http://www.w3.org/2001/XMLSchema#int"))))

;; how do Japanese call this city?
(predicate? *res* +rdf-label+ :lang "ja")
=> (("http://dbpedia.org/resource/Chernihiv"
  "http://www.w3.org/2000/01/rdf-schema#label"
  (:LITERAL-STRING "チェルニーヒウ" :LANG "ja")))

Functions

Package provides following functions:

• PARSE-NT src Parses and returns a list of triples

• PREDICATE? triples predicate &key lang data-type filters out triples with matching predicates. Additional parameters (lang and data-type) can be used to limit returned triples to those with matching language and data type specifiers.

• LITERAL-STRING triple returns the literal-string value of the g

2 Systems

The main system appears first, followed by any subsystem dependency.

2.1 cl-ntriples

Author

Victor Anyakin <anyakinvictor@yahoo.com>

License

BSD

Description

CL-NTRIPLES is a simple basic parser for Ntriples data.

Long Description

A basic parser and a set of simple utilities to parse N-Triples data.

N-Triples provides a simple format for representation of Semantic Web/W3C RDF semantic data. CL-NTRIPLES provides a simple and easy to use parser for Common Lisp applications.

Version

2012.12.16

Dependency

alexandria

Source

cl-ntriples.asd (file)

Component

src (module)

3 Modules

Modules are listed depth-first from the system components tree.

3.1 cl-ntriples/src

Parent

cl-ntriples (system)

Location

src/

Components

• package.lisp (file)
• nt-parser.lisp (file)

4 Files

Files are sorted by type and then listed depth-first from the systems components trees.

4.1 Lisp

4.1.1 cl-ntriples.asd

Location

cl-ntriples.asd

Systems

cl-ntriples (system)

Packages

cl-ntriples-asd

4.1.2 cl-ntriples/src/package.lisp

Parent

src (module)

Location

src/package.lisp

Packages

cl-ntriples

4.1.3 cl-ntriples/src/nt-parser.lisp

Dependency

package.lisp (file)

Parent

src (module)

Location

src/nt-parser.lisp

Exported Definitions

• literal-string (function)
• parse-nt (generic function)
• parse-nt (method)
• parse-nt (method)
• parse-nt (method)
• predicate? (function)

Internal Definitions

• +nt-cr+ (constant)
• +nt-lf+ (constant)
• +nt-space+ (constant)
• +nt-tab+ (constant)
• consume-whitespace (function)
• ntriple-crlf-p (function)
• ntriple-ws-p (function)
• parse-literal (function)
• parse-node-id (function)
• parse-ntriple-doc (function)
• parse-ntriple-line (function)
• parse-ntriple-triple (function)
• parse-uriref (function)

5 Packages

Packages are listed by definition order.

5.1 cl-ntriples-asd

Source

cl-ntriples.asd

Use List

• asdf/interface
• common-lisp

5.2 cl-ntriples

Source

package.lisp (file)

Nickname

nt

Use List

• alexandria.0.dev
• common-lisp

Exported Definitions

• literal-string (function)
• parse-nt (generic function)
• parse-nt (method)
• parse-nt (method)
• parse-nt (method)
• predicate? (function)

Internal Definitions

• +nt-cr+ (constant)
• +nt-lf+ (constant)
• +nt-space+ (constant)
• +nt-tab+ (constant)
• consume-whitespace (function)
• ntriple-crlf-p (function)
• ntriple-ws-p (function)
• parse-literal (function)
• parse-node-id (function)
• parse-ntriple-doc (function)
• parse-ntriple-line (function)
• parse-ntriple-triple (function)
• parse-uriref (function)

6 Definitions

Definitions are sorted by export status, category, package, and then by lexicographic order.

6.1 Exported definitions

6.1.1 Functions

Function: literal-string TRIPLE

Returns the literal-string value of the triple’s object.

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: predicate? TRIPLES PREDICATE &key LANG DATA-TYPE

Given the list of triples produced by PARSE-NT returns a list of triples with predicates matching the given one.

Package

cl-ntriples

Source

nt-parser.lisp (file)

6.1.2 Generic functions

Generic Function: parse-nt SRC

Parses N-Triples from the given source. This method
accepts a file pathname, a stream, or a string.

Returns a list of triples consisting of three elements: subject, predicate, object. Subjects can be either an ‘uriref’ or a ‘nodeID’. Objects can be of three types: ‘uriref’, ‘nodeID’ or a ‘literal’. Depending on the type of the object it is encoded into a list.

Package

cl-ntriples

Source

nt-parser.lisp (file)

Methods

Method: parse-nt (SRC pathname)

Method: parse-nt (SRC string)

Method: parse-nt (SRC stream)

6.2 Internal definitions

6.2.1 Constants

Constant: +nt-cr+

Package

cl-ntriples

Source

nt-parser.lisp (file)

Constant: +nt-lf+

Package

cl-ntriples

Source

nt-parser.lisp (file)

Constant: +nt-space+

Package

cl-ntriples

Source

nt-parser.lisp (file)

Constant: +nt-tab+

Package

cl-ntriples

Source

nt-parser.lisp (file)

6.2.2 Functions

Function: consume-whitespace STREAM

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: ntriple-crlf-p C

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: ntriple-ws-p C

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-literal STREAM

Parse the object literal from the stream.

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-node-id STREAM

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-ntriple-doc STREAM

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-ntriple-line STREAM

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-ntriple-triple STREAM

The triple consists of a: subject, predicate, object. All they are separated by whitespace. There is also a terminating full stop point in the end of a tripple.

Returns a list consisting of three elements corresponding to the tripple.

The syntax is:
triple ::= subject ws+ predicate ws+ object ws* ’.’ ws*

Package

cl-ntriples

Source

nt-parser.lisp (file)

Function: parse-uriref STREAM

Package

cl-ntriples

Source

nt-parser.lisp (file)

Appendix A Indexes

A.1 Concepts

A.2 Functions

A.3 Variables

A.4 Data types