235 lines
6.5 KiB
Prolog
235 lines
6.5 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: charsio.yap *
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* Last rev: 5/12/99 *
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* mods: *
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* comments: I/O on character strings *
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* *
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*************************************************************************/
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/**
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* @file charsio.yap
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* @author VITOR SANTOS COSTA <vsc@VITORs-MBP.lan>
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* @date Tue Nov 17 01:17:33 2015
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*
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* @brief Several operations on text.
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* @{
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*
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*/
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%% @file charsio.yap
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%%
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%%
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%% @brief Input/Output to characters.
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:- module(system(charsio), [
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format_to_chars/3,
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format_to_chars/4,
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write_to_chars/3,
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write_to_chars/2,
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atom_to_chars/3,
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atom_to_chars/2,
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number_to_chars/3,
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number_to_chars/2,
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read_from_chars/2,
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open_chars_stream/2,
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with_output_to_chars/2,
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with_output_to_chars/3,
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with_output_to_chars/4,
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term_to_atom/2
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]).
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/** @defgroup charsio Operations on Sequences of Codes.
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@ingroup library
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@{
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Term to sequence of codes conversion, mostly replaced by engine code.
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You can use the following directive to load the files.
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~~~~~~~
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:- use_module(library(charsio)).
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~~~~~~~
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It includes the following predicates:
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- atom_to_chars/2
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- atom_to_chars/3
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- format_to_chars/3
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- format_to_chars/4
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- number_to_chars/2
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- number_to_chars/3
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- open_chars_stream/2
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- read_from_chars/2
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- term_to_atom/2
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- with_output_to_chars/2
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- with_output_to_chars/3
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- with_output_to_chars/4
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- write_to_chars/2
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- write_to_chars/3
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*/
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:- meta_predicate(with_output_to_chars(0,?)).
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:- meta_predicate(with_output_to_chars(0,-,?)).
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:- meta_predicate(with_output_to_chars(0,-,?,?)).
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/** @pred format_to_chars(+ _Form_, + _Args_, - _Result_)
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Execute the built-in procedure format/2 with form _Form_ and
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arguments _Args_ outputting the result to the string of character
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codes _Result_.
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*/
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format_to_chars(Format, Args, Codes) :-
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format(codes(Codes), Format, Args).
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/** @pred format_to_chars(+ _Form_, + _Args_, - _Result_, - _Result0_)
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Execute the built-in procedure format/2 with form _Form_ and
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arguments _Args_ outputting the result to the difference list of
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character codes _Result-Result0_.
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*/
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format_to_chars(Format, Args, OUT, L0) :-
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format(codes(OUT, L0), Format, Args).
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/** @pred write_to_chars(+ _Term_, - _Result_)
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Execute the built-in procedure write/1 with argument _Term_
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outputting the result to the string of character codes _Result_.
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*/
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write_to_chars(Term, Codes) :-
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format(codes(Codes), '~w', [Term]).
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/** @pred write_to_chars(+ _Term_, - _Result0_, - _Result_)
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Execute the built-in procedure write/1 with argument _Term_
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outputting the result to the difference list of character codes
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_Result-Result0_.
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*/
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write_to_chars(Term, Out, Tail) :-
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format(codes(Out,Tail),'~w',[Term]).
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/** @pred atom_to_chars(+ _Atom_, - _Result_)
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Convert the atom _Atom_ to the string of character codes
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_Result_.
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*/
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atom_to_chars(Atom, OUT) :-
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atom_codes(Atom, OUT).
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/** @pred atom_to_chars(+ _Atom_, - _Result0_, - _Result_)
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Convert the atom _Atom_ to the difference list of character codes
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_Result-Result0_.
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*/
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atom_to_chars(Atom, L0, OUT) :-
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format(codes(L0, OUT), '~a', [Atom]).
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/** @pred number_to_chars(+ _Number_, - _Result_)
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Convert the number _Number_ to the string of character codes
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_Result_.
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*/
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number_to_chars(Number, OUT) :-
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number_codes(Number, OUT).
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/** @pred number_to_chars(+ _Number_, - _Result0_, - _Result_)
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Convert the atom _Number_ to the difference list of character codes
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_Result-Result0_.
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*/
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number_to_chars(Number, L0, OUT) :-
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var(Number), !,
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throw(error(instantiation_error,number_to_chars(Number, L0, OUT))).
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number_to_chars(Number, L0, OUT) :-
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number(Number), !,
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format(codes(L0, OUT), '~w', [Number]).
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number_to_chars(Number, L0, OUT) :-
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throw(error(type_error(number,Number),number_to_chars(Number, L0, OUT))).
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/** @pred open_chars_stream(+ _Chars_, - _Stream_)
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Open the list of character codes _Chars_ as a stream _Stream_.
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*/
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open_chars_stream(Codes, Stream) :-
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open_chars_stream(Codes, Stream, '').
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open_chars_stream(Codes, Stream, Postfix) :-
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predicate_property(memory_file:open_memory_file(_,_,_),_), !,
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memory_file:new_memory_file(MF),
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memory_file:open_memory_file(MF, write, Out),
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format(Out, '~s~w', [Codes, Postfix]),
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close(Out),
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memory_file:open_memory_file(MF, read, Stream,
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[ free_on_close(true)
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]).
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open_chars_stream(Codes, Stream, Postfix) :-
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ensure_loaded(library(memfile)),
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open_chars_stream(Codes, Stream, Postfix).
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/** @pred with_output_to_chars(? _Goal_, - _Chars_)
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Execute goal _Goal_ such that its standard output will be sent to a
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memory buffer. After successful execution the contents of the memory
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buffer will be converted to the list of character codes _Chars_.
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*/
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with_output_to_chars(Goal, Codes) :-
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with_output_to(codes(Codes), Goal).
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/** @pred with_output_to_chars(? _Goal_, ? _Chars0_, - _Chars_)
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Execute goal _Goal_ such that its standard output will be sent to a
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memory buffer. After successful execution the contents of the memory
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buffer will be converted to the difference list of character codes
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_Chars-Chars0_.
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*/
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with_output_to_chars(Goal, Codes, L0) :-
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with_output_to(codes(Codes, L0), Goal).
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%% with_output_to_chars(:Goal, -Stream, -Codes, ?Tail) is det.
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%
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% As with_output_to_chars/2, but Stream is unified with the
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% temporary stream.
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/** @pred with_output_to_chars(? _Goal_, - _Stream_, ? _Chars0_, - _Chars_)
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Execute goal _Goal_ such that its standard output will be sent to a
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memory buffer. After successful execution the contents of the memory
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buffer will be converted to the difference list of character codes
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_Chars-Chars0_ and _Stream_ receives the stream corresponding to
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the memory buffer.
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*/
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with_output_to_chars(Goal, Stream, Codes, Tail) :-
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with_output_to(codes(Codes, Tail), with_stream(Stream, Goal)).
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with_stream(Stream, Goal) :-
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current_output(Stream),
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call(Goal).
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/** @pred read_from_chars( + Chars, - Term)
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Parse the list of character codes _Chars_ and return the result in
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the term _Term_. The character codes to be read must terminate with
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a dot character such that either (i) the dot character is followed by
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blank characters; or (ii) the dot character is the last character in the
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string.
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@note The SWI-Prolog version does not require Codes to end
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in a full-stop.
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*/
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read_from_chars("", end_of_file) :- !.
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read_from_chars(List, Term) :-
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atom_to_term(List, Term, _).
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/**
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@}
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*/
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