The Krawfish Prototype is a testbed search backend for KorAP, to implement design concepts both for Kanalito and Krill.

Krawfish Prototype focusses on

• Patterns for distribution (data aggregation, sorting, grouping ...)
• Implementation of a forward index
• Normalization and optimization of complex queries
• Implementation of experimental features

Krawfish Prototype is still work in progress. The segment handling of Krawfish is based on Krill and therefore heavily inspired by Lucene and Lucy.

! This software is in its early stages and not stable yet! Use it on your own risk!

SETUP

Krawfish Prototype requires Perl of at least v5.10.1. The recommended environment is based on Perlbrew with App::cpanminus.

$ git clone https://github.com/KorAP/Krawfish-prototype
$ cd Krawfish-prototype
$ cpanm --installdeps .
$ perl Makefile.PL
$ make test

SYNOPSIS

use Krawfish::Koral;
use Krawfish::Index;

# Add documents to index
my $index = Krawfish::Index->new;
$index->introduce_field('docID' => 'de_DE');
$index->add_doc('t/data/doc1.jsonld');
$index->add_doc('t/data/doc2.jsonld');
$index->commit;

# Start KoralQuery object
my $koral = Krawfish::Koral->new;

# Define a query
# [einen|"d.*"][][Hut]
my $query = $koral->query_builder;
$koral->query(
  $query->seq(
    $query->token(
      $query->bool_or(
        'einen',
        $query->term_re('d.*')
      )
    ),
    $query->anywhere,
    $query->term('Hut')
  )
);

# Define a virtual corpus
my $corpus = $koral->corpus_builder;
$koral->corpus(
  $corpus->bool_and(
    $corpus->string('license=free'),
    $corpus->string('corpus=corpus-2')
  )
);

# Define a compilation target
my $compile = $koral->compilation_builder;
$koral->compilation(
  $compile->aggregate(
    $compile->a_fields('license'),
    $compile->a_frequencies
  ),
  $compile->enrich(
    $compile->e_fields('textLength')
  ),
  $compile->sort_by(
    $compile->s_field('docID')
  )
);

# Execute KoralQuery
my $request = $koral->to_query
  ->identify($index->dict)
  ->optimize($index->segment);

if ($request->next) {
  print $request->current_match->to_string;
};

COPYRIGHT AND LICENSE

Copyright (C) 2017, IDS Mannheim
Author: Nils Diewald

Krawfish Prototype is free software published under the BSD-2 License.