SWI-Prolog -- rdf_find

Documentation
- Reference manual
- Packages
  - SWI-Prolog Semantic Web Library 3.0
    - Plugin modules for rdf_db
      - library(semweb/rdf_litindex): Indexing words in literals
        
        rdf_find_literals/2
        
        rdf_token_expansions/2
        
        rdf_tokenize_literal/2
        
        Literal maps: Creating additional indices on literals

Availability::- use_module(library(semweb/rdf_litindex)).

rdf_find_literals(+Spec, -ListOfLiterals)

Find literals (without type or language specification) that satisfy Spec. The required indices are created as needed and kept up-to-date using hooks registered with rdf_monitor/2. Numerical indexing is currently limited to integers in the range ±2^30 (±2^62 on 64-bit platforms). Spec is defined as:

and(Spec1, Spec2): Intersection of both specifications.
or(Spec1, Spec2): Union of both specifications.
not(Spec): Negation of Spec. After translation of the full specification to Disjunctive Normal Form (DNF), negations are only allowed inside a conjunction with at least one positive literal.
case(Word): Matches all literals containing the word Word, doing the match case insensitive and after removing diacritics.
stem(Like): Matches all literals containing at least one word that has the same stem as Like using the Porter stem algorithm. See NLP package for details.
sounds(Like): Matches all literals containing at least one word that‘sounds like’ Like using the double metaphone algorithm. See NLP package for details.
prefix(Prefix): Matches all literals containing at least one word that starts with Prefix, discarding diacritics and case.
between(Low, High): Matches all literals containing an integer token in the range Low..High, including the boundaries.
ge(Low): Matches all literals containing an integer token with value Low or higher.
le(High): Matches all literals containing an integer token with value High or lower.
Token: Matches all literals containing the given token. See tokenize_atom/2 of the NLP package for details.