1:- module(diagnostics,
    2          [
    3              diagnose/1,       % +Path
    4              diagnosis_hook/3  % +Term, -Kind, -Message
    5          ]).    6
    7:- use_module(library(main)).    8:- use_module(library(prolog_colour)).    9
   10:- multifile
   11       prolog:xref_source_identfier/2,
   12       prolog:xref_open_source/2,
   13       prolog:xref_close_source/2.   14
   15
   16:- dynamic diagnostics_input/2.   17
   18
   19prolog:xref_source_identifier(Source, diagnostics_input(Source)) :-
   20    diagnostics_input(Source, _), !.
   21prolog:xref_source_identifier(diagnostics_input(Source), diagnostics_input(Source)).
   22
   23prolog:xref_open_source(diagnostics_input(Source), Stream) :-
   24    diagnostics_input(Source, Current),
   25    !,
   26    open(Current, read, Stream).
   27
   28prolog:xref_close_source(diagnostics_input(_), Stream) :-
   29    close(Stream).
   30
   31
   32:- initialization(main, main).

$ swipl -q                                \
    --on-error=status                     \
    -g "use_module(library(diagnostics))" \
    -t halt                               \
    -- path/to/source/file.pl [path/to/other/file.pl ...]

$ swipl -q                                \
    --on-error=status                     \
    -g "use_module(library(diagnostics))" \
    -t halt                               \
    -- - path/to/source/file.pl

   64main(['-', Path]) :-
   65    !,
   66    set_stream(current_input, tty(false)),
   67    set_stream(current_input, buffer(full)),
   68    tmp_file_stream(Temp, Stream, [extension(pl)]),
   69    copy_stream_data(current_input, Stream),
   70    close(Stream),
   71    absolute_file_name(Path, Abs),
   72    asserta(diagnostics_input(Abs, Temp)),
   73    diagnose(Path, diagnostics_input(Abs)).
   74main(Paths) :-
   75    maplist(absolute_file_name, Paths, Abs),
   76    maplist(diagnose, Abs).

 diagnose(+Path) is semidet

Diagnose and report issues in the Prolog source file located at Path.

Detected issues are reported via print_message/2, and can be intercepted via message_hook/3.

   84diagnose(Path) :-
   85    diagnose(Path, Path).
   86
   87diagnose(Path, Source) :-
   88    xref_source(Source),
   89    setup_call_cleanup(prolog_open_source(Source, Stream),
   90                       prolog_colourise_stream(Stream, Source, diagnosis(Path)),
   91                       prolog_close_source(Stream)).

 diagnosis_hook(+Item, -Kind, -Message) is semidet

Multifile hook, undefined by default. This hook can be used to extend the diagnosis mechanism with user defined diagnostics.

Item is a term describing a source fragment to be diagnosed, it follows the same format as the first argument of ColourItem in prolog_colourise_stream/3.

If this predicate succeeds, Kind must be unified with a message kind term that will be used as the first argument of print_message/2, while Message must be unified with a pair Format-Args where Format is a format string that will be formatted using Args. If this predicate fails, the default diagnosis logic will be used to diagnose Item.

  109:- multifile diagnosis_hook/3.  110
  111
  112diagnosis(Path, Term, Start, Length) :-
  113    diagnosis_hook(Term, Kind, Message),
  114    !,
  115    print_message(Kind, diagnostic(Path, Start, Length, Message)).
  116diagnosis(Path, Term, Start, Length) :-
  117    diagnostic(Term, Kind, Message),
  118    !,
  119    print_message(Kind, diagnostic(Path, Start, Length, Message)).
  120diagnosis(_, _, _, _).
  121
  122
  123diagnostic(head(unreferenced, Head)    , warning, "Unreferenced definition for ~w"-[PI]) :- !, pi_head(PI, Head).
  124diagnostic(syntax_error(Description, _), error  , "Syntax error ~w"-[Description]      ) :- !.
  125diagnostic(type_error(Description)     , error  , "Type error ~w"-[Description]        ) :- !.
  126diagnostic(instantiation_error         , error  , "Instantiation error"                ) :- !.
  127diagnostic(singleton                   , warning, "Singleton variable"                 ) :- !.
  128diagnostic(undefined_import            , warning, "Undefined import"                   ) :- !.
  129diagnostic(unused_import               , warning, "Unused import"                      ) :- !.
  130diagnostic(error                       , error  , "Unspecified error"                  ) :- !.
  131diagnostic(error(Error)                , error  , "Error ~w"-[Error]                   ) :- !.
  132diagnostic(goal(undefined, Head)       , error  , "Undefined predicate ~w"-[PI]        ) :- !, pi_head(PI, Head).
  133diagnostic(no_option_name              , warning, "No such option"                     ) :- !.
  134diagnostic(nofile                      , error  , "No such file"                       ) :- !.
  135diagnostic(no_flag_name(Flag)          , warning, "No such flag ~w"-[Flag]             ) :- !.
  136
  137
  138prolog:message(diagnostic(Path, Start, Length, Message)) -->
  139    [ '~w:~w:~w: '-[Path, Start, Length], Message, nl ]