1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        jan@swi-prolog.org
    5    WWW:           https://www.swi-prolog.org
    6    Copyright (c)  2013-2026, VU University Amsterdam
    7                              SWI-Prolog Solutions b.v.
    8    All rights reserved.
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   11    modification, are permitted provided that the following conditions
   12    are met:
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   15       notice, this list of conditions and the following disclaimer.
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   18       notice, this list of conditions and the following disclaimer in
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   34*/
   35
   36:- module(prolog_console_input,
   37          [
   38          ]).   39:- autoload(library(lists), [reverse/2, append/2]).   40:- autoload(library(dcg/basics), [remainder/3]).   41:- autoload(library(apply), [maplist/3, convlist/3]).

   52:- multifile
   53    prolog:complete_input/4.

 prolog:complete_input(+BeforeCursor:string, +AfterCursor:string, -Delete:atom, -Completions:list) is semidet

Compute auto completions for the input line BeforeCursor+AfterCursor. Implemented completions

• Files<br>
  • Text starting '<prefix> (single quotes) is completed as a file. If there is a single matching file a terminating `'` is added.
  • If the start of the line is [<prefix> and text can be a non-quoted atom, look for Prolog files with this name. Directories can be inserted as / (unquoted), as long as each segment is a valid atom. If a single .pl file is found it is closed with ], without the extension.
  • Text starting library(<prefix> is completed as a library file using the same rules as [<prefix>, but looking in all library directories instead of the current directory.
• Atoms
  <prefix> is used to complete atoms that can be written without quotes (excluding symbol atoms such as -->) and are permanent, i.e., have references from clauses records, flags, foreign code, etc.
• Variables
  <Prefix> is completed as an atom if it is a valid variable name. It is completed with other atoms from the query being edited using the same search as Emacs dabbrev (Dynamic Abbreviation). $<Prefix> expands to saved toplevel variables.

Arguments:

Delete	- is an atom or string representing the text that is replaced by the completion
Completions	- is a list of elements of this shape: Atom Used for a plain completion without comment Atom - Comment Used for a completion with comment. This will be used for predicates.

   96prolog:complete_input(Before, After, Delete, Completions) :-
   97    string_codes(Before, Chars),
   98    reverse(Chars, BeforeRev),
   99    complete(BeforeRev, After, Delete, Completions).
  100
  101complete(BeforeRev, _After, Prefix, Files) :-   % complete files
  102    phrase(file_prefix(Prefix, Type), BeforeRev),
  103    !,
  104    (   Type = library(Close)
  105    ->  complete_library(Prefix, Close, Files)
  106    ;   atom_concat(Prefix, '*', Pattern),
  107        expand_file_name(Pattern, Files0),
  108        finish_file_name(Files0, Type, Files)
  109    ).
  110complete(BeforeRev, After, Prefix, Completions) :-   % complete atoms
  111    phrase(identifier_prefix_r(Prefix, Type), BeforeRev, BeforeRev1),
  112    !,
  113    identifier_completions(Type, Prefix, BeforeRev1, After, Completions).
  114
  115identifier_completions(atom, Prefix, _, _, Atoms) :-
  116    '$atom_completions'(Prefix, Atoms).
  117identifier_completions(var, Prefix, BeforeRev, After, Vars) :-
  118    findall(Var, var_starts(Prefix, BeforeRev, After, Var), Vars0),
  119    sort(Vars0, Vars).
  120
  121var_starts(Prefix, [0'$|_], _After, Var) :-        % $Var
  122    !,
  123    recorded('$topvar', Var = _),
  124    sub_atom(Var, 0, _, _, Prefix).
  125var_starts(Prefix, BeforeRev, _After, Var) :-        % Backard search
  126    phrase((..., nonid_char, identifier_prefix_r(Var, var)),
  127           BeforeRev, _),
  128    sub_string(Var, 0, _, _, Prefix).
  129var_starts(Prefix, _BeforeRev, AfterString, Var) :-  % Forward search
  130    string_codes(AfterString, After),
  131    phrase((..., nonid_char, identifier_prefix(Var, var)),
  132           After, _),
  133    sub_string(Var, 0, _, _, Prefix).
  134
  135... --> [] ; [_], ... .
  136
  137nonid_char -->
  138    [C],
  139    { \+ code_type(C, prolog_identifier_continue) }.

 identifier_prefix(-Prefix, -Type) is semidet

 identifier_prefix_r(-Prefix, -Type) is semidet

  144identifier_prefix(Prefix, Type) -->
  145    atom_chars(String),
  146    { String = [H|_],
  147      (   code_type(H, prolog_var_start)
  148      ->  Type = var
  149      ;   Type = atom
  150      ),
  151      string_codes(Prefix, String) % do not create an atom
  152    }.
  153
  154identifier_prefix_r(Prefix, Type) -->
  155    atom_chars(RevString),
  156    { reverse(RevString, String),
  157      String = [H|_],
  158      (   code_type(H, prolog_var_start)
  159      ->  Type = var
  160      ;   Type = atom
  161      ),
  162      string_codes(Prefix, String) % do not create an atom
  163    }.
  164
  165atom_chars([H|T]) --> atom_char(H), !, atom_chars(T).
  166atom_chars([]) --> [].
  167
  168atom_char(C) --> [C], { atom_char(C) }.
  169
  170atom_char(C) :- code_type(C, prolog_identifier_continue).

 file_prefix(-Prefix, -Type)// is semidet

True when the part before the cursor looks like a file name.

  176file_prefix(Prefix, file) -->
  177    file_chars(RevString, quoted('\'')), "'",
  178    !,
  179    remainder(_),
  180    { reverse(RevString, String),
  181      atom_codes(Prefix, String)
  182    }.
  183file_prefix(Prefix, consult(']')) -->
  184    file_chars(RevString, unquoted), "[",
  185    !,
  186    { reverse(RevString, String),
  187      atom_codes(Prefix, String)
  188    }.
  189file_prefix(Prefix, library(')')) -->
  190    file_chars(RevString, unquoted), "(yrarbil",
  191    !,
  192    remainder(_),
  193    { reverse(RevString, String),
  194      atom_codes(Prefix, String)
  195    }.
  196
  197file_chars([H|T], Style) --> file_char(H, Style), !, file_chars(T, Style).
  198file_chars([], _) --> [].
  199
  200file_char(C, Style) --> [C], { file_char(C, Style) }.
  201
  202file_char(C, _) :- code_type(C, csym).
  203file_char(0'/, _).
  204file_char(C, quoted(_)) :-
  205    file_char(C).
  206
  207file_char(0'.).
  208file_char(0'-).
  209file_char(0'~).
  210:- if(current_prolog_flag(windows,true)).  211file_char(0':).
  212file_char(0'\s).
  213:- endif.

 finish_file_name(+Matches, -Completions) is det

Add closing quote for a unique file name.

  219finish_file_name([Dir0], _, [Dir]) :-
  220    exists_directory(Dir0),
  221    !,
  222    atom_concat(Dir0, '/', Dir).
  223finish_file_name([File0], Close, [File]) :-
  224    exists_file(File0),
  225    close_file_name(File0, Close, File),
  226    !.
  227finish_file_name(Files0, _, Files) :-
  228    maplist(tag_dir, Files0, Files).
  229
  230tag_dir(Dir, DirS) :-
  231    exists_directory(Dir),
  232    !,
  233    atom_concat(Dir, /, DirS).
  234tag_dir(File, File).
  235
  236close_file_name(File0, consult(Close), File) :-
  237    file_name_extension(Base, Ext, File0),
  238    user:prolog_file_type(Ext, prolog),
  239    atom_concat(Base, Close, File).
  240close_file_name(File0, quoted(Close), File) :-
  241    atom_concat(File0, Close, File).

 complete_library(+Prefix:atom, +Close:atom, -Completions:list) is semidet

Complete to a library entry on "library(Prefix".

  248complete_library(Prefix, Close, Libraries) :-
  249    findall(Pairs, complete_one_libdir(Prefix, Pairs), DirPairs),
  250    (   DirPairs = [LibDir-[f(File)]]
  251    ->  atom_concat(LibDir, Local, File),
  252        atom_concat(Local, Close, Completion),
  253        Libraries = [Completion]
  254    ;   DirPairs = [LibDir-[d(Dir)]]
  255    ->  atom_concat(LibDir, Local, Dir),
  256        atom_concat(Local, '/', Completion),
  257        Libraries = [Completion]
  258    ;   maplist(local_libs, DirPairs, FilesLists),
  259        append(FilesLists, Libraries0),
  260        sort(Libraries0, Libraries)
  261    ).
  262
  263complete_one_libdir(Prefix, LibdirS-Files) :-
  264    absolute_file_name(library(.), LibDir,
  265                       [ file_type(directory),
  266                         solutions(all)
  267                       ]),
  268    atom_concat(LibDir, /, LibdirS),
  269    atomic_list_concat([LibdirS, Prefix, '*'], Pattern),
  270    expand_file_name(Pattern, Entries),
  271    convlist(dir_or_source, Entries, Files0),
  272    sort(Files0, Files),
  273    Files \== [].
  274
  275local_libs(LibDir-Members, Locals) :-
  276    maplist(local_file_name(LibDir), Members, Locals).
  277
  278local_file_name(LibDir, f(File), Local) :-
  279    atom_concat(LibDir, Local, File).
  280local_file_name(LibDir, d(Dir), Local) :-
  281    atom_concat(LibDir, Local0, Dir),
  282    atom_concat(Local0, /, Local).
  283
  284dir_or_source(Entry, f(Plain)) :-
  285    file_name_extension(Plain, Ext, Entry),
  286    user:prolog_file_type(Ext, prolog),
  287    !.
  288dir_or_source(Entry, d(Entry)) :-
  289    exists_directory(Entry)