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Pack canny_tudor -- prolog/swi/settings.pl
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 local_settings_file(-LocalFile:atom) is semidet
Breaks the module interface by asking for the current local settings file from the settings module. The local_file/1 dynamic predicate retains the path of the current local file based on loading. Loading a new settings file using load_settings/1 pushes a new local file without replacing the old one, so that the next save_settings/0 keeps saving to the original file.
LocalFile- is the absolute path of the local settings file to be utilised by the next save_settings/1 predicate call.
 setting(:Name, ?Value, :Goal) is semidet
Semi-deterministic version of setting/2. Succeeds only if Value succeeds for Goal; fails otherwise. Calls Goal with Value.

Take the following example where you only want the setting predicate to succeed when it does not match the empty atom.

setting(http:public_host, A, \==(''))