Xapian::Stem Class Reference

Class representing a stemming algorithm. More...

## Public Member Functions

| Stem (const Stem &o)
| Copy constructor.
Stem & | operator= (const Stem &o)
| Assignment.
| Stem ()
| Construct a Xapian::Stem object which doesn't change terms. More...
| Stem (const std::string &language)
| Construct a Xapian::Stem object for a particular language. More...
| Stem (StemImplementation *p)
| Construct a Xapian::Stem object with a user-provided stemming algorithm. More...
| ~Stem ()
| Destructor.
std::string | operator() (const std::string &word) const
| Stem a word. More...
std::string | get_description () const
| Return a string describing this object.

## Static Public Member Functions

static std::string | get_available_languages ()
| Return a list of available languages. More...

## Detailed Description

Class representing a stemming algorithm.

## Constructor & Destructor Documentation

## Stem() [1/3]

Xapian::Stem::Stem | ( |  | ) |

Construct a Xapian::Stem object which doesn't change terms.

Equivalent to Stem("none").

## Stem() [2/3]

Xapian::Stem::Stem | ( | const std::string & | language | ) |

explicit

Construct a Xapian::Stem object for a particular language.

Parameters

  language | Either the English name for the language or the two letter ISO639 code.

The following language names are understood (aliases follow the name):

- none - don't stem terms
- armenian (hy)
- basque (eu)
- catalan (ca)
- danish (da)
- dutch (nl)
- english (en) - Martin Porter's 2002 revision of his stemmer
- earlyenglish - Early English (e.g. Shakespeare, Dickens) stemmer
- english_lovins (lovins) - Lovin's stemmer
- english_porter (porter) - Porter's stemmer as described in his 1980 paper
- finnish (fi)
- french (fr)
- german (de)
- german2 - Normalises umlauts and ß
- hungarian (hu)
- italian (it)
- kraaij_pohlmann - A different Dutch stemmer
- norwegian (nb, nn, no)
- portuguese (pt)
- romanian (ro)
- russian (ru)
- spanish (es)
- swedish (sv)
- turkish (tr)

Exceptions

  Xapian::InvalidArgumentError | is thrown if language isn't recognised.

## Stem() [3/3]

Xapian::Stem::Stem | ( | StemImplementation * | p | ) |

explicit

Construct a Xapian::Stem object with a user-provided stemming algorithm.

You can subclass Xapian::StemImplementation to implement your own stemming algorithm (or to wrap a third-party algorithm) and then wrap your implementation in a Xapian::Stem object to pass to the Xapian API.

Parameters

  p | The user-subclassed StemImplementation object. This is reference counted, and so will be automatically deleted by the Xapian::Stem wrapper when no longer required.

## Member Function Documentation

## get_available_languages()

static std::string Xapian::Stem::get_available_languages | ( |  | ) |

inline static

Return a list of available languages.

Each stemmer is only included once in the list (not once for each alias). The name included is the English name of the language.

The list is returned as a string, with language names separated by spaces. This is a static method, so a Xapian::Stem object is not required for this operation.

## operator()()

std::string Xapian::Stem::operator() | ( | const std::string & | word | ) | const

Stem a word.

Parameters

  word | a word to stem.

Returns
  the stem

The documentation for this class was generated from the following file:

- xapian/stem.h