SWI-Prolog -- snowball/3

Documentation
- Reference manual
- Packages
  - SWI-Prolog Natural Language Processing Primitives
    - library(snowball): The Snowball multi-lingual stemmer library
      - snowball/3
      - snowball_current_algorithm/1

Availability::- use_module(library(snowball)).(can be autoloaded)

[det]snowball(+Algorithm, +Input, -Stem)

Apply the Snowball Algorithm on Input and unify the result (an atom) with Stem.

The implementation maintains a cache of stemmers for each thread that accesses snowball/3, providing high-perfomance and thread-safety without locking.

`Algorithm`	is the (english) name for desired algorithm or an 2 or 3 letter ISO 639 language code.
`Input`	is the word to be stemmed. It is either an atom, string or list of chars/codes. The library accepts Unicode characters. `Input` must be lowercase. See downcase_atom/2.

Errors: - domain_error(snowball_algorithm, Algorithm)
- type_error(atom, Algorithm)
- type_error(text, Input)