doc_markdown.pl

/*  Part of SWI-Prolog

    Author:        Jan Wielemaker
    E-mail:        jan@swi-prolog.org
    WWW:           http://www.swi-prolog.org
    Copyright (c)  2023, SWI-Prolog Solutions b.v.
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*/

:- module(pldoc_markdown,
          [ print_markdown/2            % +String, +Options
          ]).
:- use_module(library(pldoc)).
:- autoload(library(pldoc/doc_html)).
:- autoload(library(pldoc/doc_wiki), [wiki_codes_to_dom/3]).
:- autoload(library(sgml), [load_html/3]).
:- autoload(library(http/html_write), [html/3, print_html/1]).
:- use_module(library(lynx/pldoc_style), []).
:- autoload(library(lynx/html_text), [html_text/2]).

:- predicate_options(print_markdown/2, 2,
                     [ pass_to(wiki_codes_to_dom/3, 2),
                       pass_to(load_html/3, 3),
                       pass_to(html_text/2, 2)
                     ]).

/** <module> Markdown utilities

This module provides high level PlDoc markdown utilities.

@tbd	The current implementation creates the markdown DOM, translates
        this to HTML, then parses it and feeds it into the HTML
        rendering.  Creating an parsing the HTML string representation
        could be skipped.
*/

%!  print_markdown(+Input, +Options) is det.
%
%   Print a PlDoc  markdown  formatted   String  to  `current_output` as
%   formatted text.
%
%   @arg Input is either a term `Format-Args`, a atom, string, or a list
%   of codes.
%   @see html_text/2 for the most useful options.

print_markdown(String, Options) :-
    to_codes(String, Codes),
    wiki_codes_to_dom(Codes, Options, DOM1),
    phrase(html(DOM1), Tokens),
    with_output_to(string(HTML), print_html(Tokens)),
    setup_call_cleanup(
        open_string(HTML, In),
        load_html(In, DOM, Options),
        close(In)),
    html_text(DOM, Options).

to_codes(Fmt-Args, Codes) =>
    format(codes(Codes), Fmt, Args).
to_codes(String, Codes), atomic(String) =>
    string_codes(String, Codes).
to_codes(List, Codes), is_of_type(List, Codes) =>
    Codes = List.