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https://github.com/ljos/sparql-mode

A SPARQL mode for emacs
https://github.com/ljos/sparql-mode

emacs-lisp emacs-mode semantic-web sparql

Last synced: about 2 months ago
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A SPARQL mode for emacs

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README 

        
* What is it?

  A major mode for emacs that provides syntax highlighting for

  [[http://www.w3.org/TR/sparql11-query/][SPARQL]]. It also provides a way to execute queries against a SPARQL

  HTTP endpoint, such as is provided by [[http://jena.apache.org/documentation/serving_data/][Fuseki]]. It is also possible to

  query other endpoints like [[http://dbpedia.org/sparql][DBPedia]].



* Getting Started

  [[https://melpa.org/#/sparql-mode][file:https://melpa.org/packages/sparql-mode-badge.svg]] [[https://stable.melpa.org/#/sparql-mode][file:https://stable.melpa.org/packages/sparql-mode-badge.svg]]

  - Download sparql-mode and put it in a directory somewhere.

  - Add the following to your .emacs file



  #+BEGIN_SRC emacs-lisp

  (add-to-list 'load-path "/path/to/sparql-mode-dir")

  (autoload 'sparql-mode "sparql-mode.el"

      "Major mode for editing SPARQL files" t)

  (add-to-list 'auto-mode-alist '("\\.sparql$" . sparql-mode))

  (add-to-list 'auto-mode-alist '("\\.rq$" . sparql-mode))

  #+END_SRC



  Now sparql-mode will load whenever you visit a file whose name ends

  with .sparql. Alternatively, run =M-x sparql-mode= in an existing

  buffer containing SPARQL commands.



  It is also possible to add

  #+BEGIN_SRC emacs-lisp

   -*- mode: sparql -*-

  #+END_SRC

  to the top of the file. This is a comment read by emacs to discover

  what mode to use.



** Auto complete

   SPARQL-mode has basic support for both =auto-complete-mode= and

   =company-mode=. Just add your favourite completion mode to

   =sparql-mode-hook=.



   #+BEGIN_SRC emacs-lisp

     (add-hook 'sparql-mode-hook 'your-favourite-completion-mode)

   #+END_SRC



* Executing SPARQL Queries from within Emacs

  From a buffer that is in sparql-mode, execute =M-x

  sparql-query-region=. You will be prompted for a SPARQL HTTP

  endpoint in the minibuffer, which defaults to

  =http://localhost:2020/=. Once set, it will be used for all

  subsequent queries in that buffer.  Results will be displayed in

  another buffer in CSV format.



* Org-babel support

  It is also possible to use =sparql-mode= with org-mode and executing

  queries with org-babel. You can do that by adding the following

  snippet or adding =(sparql . t)= to languages org-babel can load:



  #+BEGIN_SRC emacs-lisp

  (org-babel-do-load-languages

   'org-babel-load-languages

   '((sparql . t)))

  #+END_SRC



  You can then execute the query by pressing =C-c C-c= on the

  source-block header.



  By default results formatted as =text/csv= will be converted to an

  org table. This can be disabled by adding =:results scalar= to the

  header. See examples.



*** Example

    Default behaviour for results in csv is to convert the result to a

    table:



    #+BEGIN_SRC org

      ,#+BEGIN_SRC sparql :url https://live.dbpedia.org/sparql :format text/csv

        SELECT DISTINCT ?Concept WHERE {

          [] a ?Concept

        } LIMIT 5

      ,#+END_SRC



      ,#+RESULTS:

      | Concept                                                          |

      |------------------------------------------------------------------|

      | http://www.openlinksw.com/schemas/virtrdf#QuadMapFormat          |

      | http://www.openlinksw.com/schemas/virtrdf#QuadStorage            |

      | http://www.openlinksw.com/schemas/virtrdf#array-of-QuadMapFormat |

      | http://www.openlinksw.com/schemas/virtrdf#QuadMap                |

      | http://www.openlinksw.com/schemas/virtrdf#QuadMapValue           |

    #+END_SRC



    If you don't want to convert the result to a table, you can

    override that behaviour by specifying that the result should be

    =scalar=:



    #+BEGIN_SRC org

      ,#+HEADER: :url https://live.dbpedia.org/sparql

      ,#+HEADER: :format text/csv

      ,#+HEADER: :results scalar

      ,#+BEGIN_SRC sparql

        SELECT DISTINCT ?Concept WHERE {

          [] a ?Concept

        } LIMIT 5

      ,#+END_SRC



      ,#+RESULTS:

      : "Concept"

      : "http://www.openlinksw.com/schemas/virtrdf#QuadMapFormat"

      : "http://www.openlinksw.com/schemas/virtrdf#QuadStorage"

      : "http://www.openlinksw.com/schemas/virtrdf#array-of-QuadMapFormat"

      : "http://www.openlinksw.com/schemas/virtrdf#QuadMap"

      : "http://www.openlinksw.com/schemas/virtrdf#QuadMapValue"

    #+END_SRC



    We can also declare variables that will then be expanded before

    execution. For example the following query:



    #+BEGIN_SRC sparql :var x="friend:Julia"

      SELECT * WHERE {

        ?x foaf:name ?name.

        $x foaf:email ?email.

      }

    #+END_SRC



    will be transformed into the following before it is executed:



    #+BEGIN_SRC sparql

      SELECT * WHERE {

        friend:Julia foaf:name ?name.

        friend:Julia foaf:email ?email.

      }

    #+END_SRC



    Notice that =$x= and =?x= are treated as identical. This is

    because SPARQL treats them as identical.



    By combining this with the =#+call= syntax we can create and reuse

    queries:



    #+BEGIN_SRC org

      ,#+NAME: count-statements-in-graph

      ,#+BEGIN_SRC sparql :var graph="<>"

        SELECT (COUNT(*) AS ?count) WHERE {

          GRAPH $graph {

            ?s ?p ?o .

          }

        }

      ,#+END_SRC



      ,#+CALL: count-statements-in-graph("")



      ,#+RESULTS:

      | count |

      |-------|

      |  1001 |



      ,#+CALL: count-statements-in-graph("")



      ,#+RESULTS:

      | count |

      |-------|

      |   100 |



    #+END_SRC



    Notice that the server request is done synchronously and will

    therefore lock the editor if the request takes a long time.



* Bugs and Enhancements

  If you have a problem or would like to see it get better in a

  specific way, feel free to drop an issue in [[https://github.com/ljos/sparql-mode/issues][the issue tracker]].

  Enjoy!