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prologiso-prologtuprolog

How can I write key-value pairs in Prolog?

Imagine I have the following predicate, which states that the ID loc1 designates a location.

isLocation('loc1', 'Location 1').

I want to provide translations for the second text (Location 1), i. e. key-value pairs such as en='Location 1', de='Ort 1', ru='Местоположение 1'.

What is the correct way to encode such data in Prolog, especially TuProlog (and ideally - standardized Prolog) ?

Would the notation below work outside SWI Prolog?

isLocation('loc1', ['en'-'Location 1', 'de'-'Ort 1', 'ru'-'Местоположение 1']]).
Solution

  • the easiest way, working in any Prolog, uses member/2 to retrieve key-value pairs. For instance

    l10n(MessageId, Country, Translated) :-
  isLocation(MessageId, Localized),
  member(Country-Translated, Localized).

    Such basic construct would need of course several improvements, depending on requirements.