link-rdflib/lib/query-to-sparql.js

an RDF library for node.js, patched for speed.

"use strict";

var log = require('./log');

function queryToSPARQL(query) {
  var indent = 0;

  function getSelect(query) {
    var str = addIndent() + 'SELECT ';

    for (var i = 0; i < query.vars.length; i++) {
      str += query.vars[i] + ' ';
    }

    str += '\n';
    return str;
  }

  function getPattern(pat) {
    var str = '';
    var st = pat.statements;

    for (var x in st) {
      log.debug('Found statement: ' + st);
      str += addIndent() + st[x] + '\n';
    }

    return str;
  }

  function getConstraints(pat) {
    var str = '';

    for (var v in pat.constraints) {
      var foo = pat.constraints[v];
      str += addIndent() + 'FILTER ( ' + foo.describe(v) + ' ) ' + '\n';
    }

    return str;
  }

  function getOptionals(pat) {
    var str = '';

    for (var x = 0; x < pat.optional.length; x++) {
      // alert(pat.optional.termType)
      log.debug('Found optional query');
      str += addIndent() + 'OPTIONAL { ' + '\n';
      indent++;
      str += getPattern(pat.optional[x]);
      str += getConstraints(pat.optional[x]);
      str += getOptionals(pat.optional[x]);
      indent--;
      str += addIndent() + '}' + '\n';
    }

    return str;
  }

  function getWhere(pat) {
    var str = addIndent() + 'WHERE \n' + '{ \n';
    indent++;
    str += getPattern(pat);
    str += getConstraints(pat);
    str += getOptionals(pat);
    indent--;
    str += '}';
    return str;
  }

  function addIndent() {
    var str = '';

    for (var i = 0; i < indent; i++) {
      str += '    ';
    }

    return str;
  }

  function getSPARQL(query) {
    return getSelect(query) + getWhere(query.pat);
  }

  return getSPARQL(query);
}

module.exports = queryToSPARQL;