hfst / hfst-ospell

HFST spell checker library and command line tool

Hfst-ospell library and toy commandline tester

This is a minimal hfst optimized lookup format based spell checker library and a demonstrational implementation of command line based spell checker. The library is licenced under Apache licence version 2, other licences can be obtained from University of Helsinki.

Dependencies

• libxml++2
• libarchive

Debian packages for dependencies

• libxml++2-dev
• libarchive-dev

Usage

Usage in external programs:

#include <ospell.h>

and compile your project with:

$(pkg-config --cflags hfstospell)

and link with:

$(pkg-config --libs hfstospell)

Programming examples

The library lives in a namespace called hfst_ospell. Pass (weighted!) Transducer pointers to the Speller constructor, eg.:

FILE * error_source = fopen(error_filename, "r");
FILE * lexicon_file = fopen(lexicon_filename, "r");
hfst_ospell::Transducer * error;
hfst_ospell::Transducer * lexicon;
try {
    error = new hfst_ospell::Transducer(error_source);
    lexicon = new hfst_ospell::Transducer(lexicon_file);
} catch (hfst_ospell::TransducerParsingException& e) {
        /* problem with transducer file, usually completely
        different type of file - there's no magic number
        in the header to check for this */
    }
hfst_ospell::Speller * speller;
try {
    speller = new hfst_ospell::Speller(error, lexicon);
} catch (hfst_ospell::AlphabetTranslationException& e) {
    /* problem with translating between the two alphabets */
}

And use the functions:

// returns true if line is found in lexicon
bool hfst_ospell::Speller::check(char * line);

// CorrectionQueue is a priority queue, sorted by weight
hfst_ospell::CorrectionQueue hfst_ospell::Speller::correct(char * line);

to communicate with it. See main.cc for a concrete usage example.

Command-line tool

Main.cc provides a demo utility with the following help message:

Usage: hfst-ospell [OPTIONS] ERRORSOURCE LEXICON
Run a composition of ERRORSOURCE and LEXICON on standard input and
print corrected output

  -h, --help                  Print this help message
  -V, --version               Print version information
  -v, --verbose               Be verbose
  -q, --quiet                 Don't be verbose (default)
  -s, --silent                Same as quiet


Report bugs to [e-mail]

Use in real-world applications

The HFST based spellers can be used in real applications with help of voikko. Voikko in turn can be used with enchant, libreoffice, and firefox.