/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2018-2020, CWI Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(text_format, [ format_paragraph/2, % +Text, +Options trim_line/2 % +LineIn, -Line ]). :- use_module(library(debug),[debug/3]). :- autoload(library(ansi_term),[ansi_format/3]). :- autoload(library(error),[must_be/2,type_error/2]). :- autoload(library(lists),[append/3,member/2,selectchk/3]). :- autoload(library(option),[select_option/3,option/2,option/3]). /** Print formatted text to a terminal This module is the core of the plain text rendering module, providing format_paragraph/2 which formats a plain text block, respecting left and right margins, text alignment, ANSI style elements, etc. */ :- multifile words/2. % +Input, -Words %! format_paragraph(+Text, +Options) % % Format a paragraph to the current output. Options defined are: % % - width(+Width) % Width of a line. Default is 72. % - margin_left(+Indent) % Indent all lines with Indent spaces. % - margin_right(+Margin) % Additional right margin (same as reducing `width`) % - hang(+Hang) % Additional indent for the first line. Can be negative. % - bullet(+Bullet) % Bullet placed before the first line. % - text_align(Alignment) % One of `left`, `right`, `center` or `justify` % - pad(+Char) % If present, padd to the right using Char. Currently % Char *must be* ' '. format_paragraph(Text, Options) :- words(Text, Words), format_lines(Words, 1, Options). format_lines([], _, _). format_lines(Words, LineNo, Options) :- line_width(LineNo, Width, Options), skip_spaces(Words, Words1), take_words(Words1, 0, Width, Line0, HasBR, Words2), skip_trailing_spaces(Line0, Line), skip_spaces(Words2, Words3), ( Words3 == [] -> align_last_line(Options, OptionsLast), format_line(Line, Width, LineNo, OptionsLast) ; HasBR == true -> align_last_line(Options, OptionsLast), format_line(Line, Width, LineNo, OptionsLast), LineNo1 is LineNo + 1, format_lines(Words3, LineNo1, Options) ; format_line(Line, Width, LineNo, Options), LineNo1 is LineNo + 1, format_lines(Words3, LineNo1, Options) ). take_words([br(_)|T], _, _, [], true, T) :- !. take_words([H|T0], X, W, [H|T], BR, Rest) :- element_length(H, Len), X1 is X+Len, ( X1 =< W -> true ; X == 0 % take at least one word ), !, take_words(T0, X1, W, T, BR, Rest). take_words(Rest, _, _, [], false, Rest). %! trim_line(Line0, Line) is det. % % Remove leading and trailing white space (b(_,_)) tokens from a line. trim_line(Line0, Line) :- skip_spaces(Line0, Line1), skip_trailing_spaces(Line1, Line). skip_spaces([b(_,_)|T0], T) :- !, skip_spaces(T0, T). skip_spaces(L, L). skip_trailing_spaces(L, []) :- skip_spaces(L, []), !. skip_trailing_spaces([H|T0], [H|T]) :- skip_trailing_spaces(T0, T). align_last_line(Options0, Options) :- select_option(text_align(justify), Options0, Options1), !, Options = [text_align(left)|Options1]. align_last_line(Options, Options). %! format_line(+Line, +Width, +LineNo, +Options) is det. format_line(Line, Width, LineNo, Options) :- option(pad(Char), Options), option(margin_right(MR), Options), MR > 0, !, must_be(oneof([' ']), Char), % For now format_line_(Line, Width, LineNo, Options), forall(between(1, MR, _), put_char(' ')). format_line(Line, Width, LineNo, Options) :- format_line_(Line, Width, LineNo, Options). format_line_(Line, Width, LineNo, Options) :- float_right(Line, Line1, Right), !, trim_line(Line1, Line2), % TBD: Alignment with floats trim_line(Right, Right2), space_dim(Line2, _, WL), space_dim(Right2, _, WR), append(Line2, [b(0,Space)|Right2], Line3), Space is Width - WL - WR, emit_indent(LineNo, Options), emit_line(Line3). format_line_(Line, Width, LineNo, Options) :- option(text_align(justify), Options), !, justify(Line, Width), emit_indent(LineNo, Options), emit_line(Line). format_line_(Line, Width, LineNo, Options) :- option(text_align(right), Options), !, flush_right(Line, Width, LineR), emit_indent(LineNo, Options), emit_line(LineR). format_line_(Line, Width, LineNo, Options) :- option(text_align(center), Options), option(pad(Pad), Options, _), !, center(Line, Width, Pad, LineR), emit_indent(LineNo, Options), emit_line(LineR). format_line_(Line, Width, LineNo, Options) :- option(pad(_Char), Options), !, pad(Line, Width, Padded), emit_indent(LineNo, Options), emit_line(Padded). format_line_(Line, _Width, LineNo, Options) :- emit_indent(LineNo, Options), emit_line(Line). justify(Line, Width) :- space_dim(Line, Spaces, W0), Spread is Width - W0, length(Spaces, SPC), SPC > 0, Spread > 0, spread(Spread, SPC, Spaces), !, debug(format(justify), 'Justified ~d spaces over ~d gaps: ~p', [Spread, SPC, Spaces]). justify(_, _). flush_right(Line, Width, [b(0,Spaces)|Line]) :- space_dim(Line, _Spaces, W0), Spaces is Width - W0. center(Line, Width, Pad, [b(0,Left)|Padded]) :- space_dim(Line, _Spaces, W0), Spaces is Width - W0, Left is Spaces//2, ( atom(Pad), Right is Spaces - Left, Right > 0 -> append(Line, [b(0,Right)], Padded) ; Padded = Line ). pad(Line, Width, Padded) :- space_dim(Line, _Spaces, W0), Spaces is Width - W0, append(Line, [b(0,Spaces)], Padded). %! float_right(+Line0, -Line, -Right) is semidet. % % float_right(Line0, Line, Right) :- member(w(_,_,Attrs), Line0), memberchk(float(right), Attrs), !, do_float_right(Line0, Line, Right). do_float_right([], [], []). do_float_right([H0|T0], T, [H|R]) :- float_right_word(H0, H), !, float_right_space(T0, T, R). do_float_right([H|T0], [H|T], R) :- do_float_right(T0, T, R). float_right_word(w(W,L,A0), w(W,L,A)) :- selectchk(float(right), A0, A). float_right_space([S|T0], T, [S|R]) :- S = b(_,_), !, float_right_space(T0, T, R). float_right_space(Line0, Line, Right) :- do_float_right(Line0, Line, Right). %! space_dim(+Line, -SpaceVars, -Width) space_dim(Line, Spaces, Width) :- space_dim(Line, Spaces, 0, Width). space_dim([], [], Width, Width). space_dim([b(L,Var)|T0], [Var|T], W0, W) :- !, W1 is W0+L, space_dim(T0, T, W1, W). space_dim([H|T0], T, W0, W) :- word_length(H, L), !, W1 is W0+L, space_dim(T0, T, W1, W). %! spread(+Spread, +SPC, -Spaces) % % Distribute Spread spaces over SPC places, producing a list of % counts. spread(Spread, SPC, Spaces) :- spread_spc(SPC, Spread, Spaces). spread_spc(Cnt, Spread, [H|T]) :- Cnt > 0, !, H is round(Spread/Cnt), Cnt1 is Cnt - 1, Spread1 is Spread-H, spread_spc(Cnt1, Spread1, T). spread_spc(_, _, []). %! emit_line(+Content) % emit_line([]). emit_line([H|T]) :- ( emit_line_element(H) -> true ; type_error(line_element, H) ), emit_line(T). emit_line_element(w(W,_, Attrs)) :- ( Attrs = [] -> write(W) ; ansi_format(Attrs, '~w', [W]) ). emit_line_element(b(Len, Extra)) :- ( var(Extra) -> Extra = 0 ; true ), Spaces is Len+Extra, forall(between(1, Spaces, _), put_char(' ')). emit_indent(1, Options) :- !, option(margin_left(Indent), Options, 0), option(hang(Hang), Options, 0), ( option(bullet(BulletSpec), Options) -> bullet_text(BulletSpec, Bullet), atom_length(Bullet, BLen), TheIndent is Indent+Hang-1-BLen, emit_indent(TheIndent), format('~w ', [Bullet]) ; TheIndent is Indent+Hang, emit_indent(TheIndent) ). emit_indent(_, Options) :- option(margin_left(Indent), Options, 0), nl, emit_indent(Indent). emit_indent(N) :- forall(between(1, N, _), put_char(' ')). line_width(1, Width, Options) :- !, option(width(Right), Options, 72), option(margin_left(Indent), Options, 0), option(margin_right(RightMargin), Options, 0), option(hang(Hang), Options, 0), Width is Right - (Indent+Hang) - RightMargin. line_width(_, Width, Options) :- option(width(Right), Options, 72), option(margin_left(Indent), Options, 0), option(margin_right(RightMargin), Options, 0), Width is Right - Indent - RightMargin. %! words(+Input, -Words) is det. % % Turn the Input into a list of w(Word, Len, Attributes) terms. words(Text, Words) :- string(Text), !, split_string(Text, " \n\t\r", " \n\t\r", Words0), phrase(word_spaces(Words0), Words). words(Words, Words) :- is_list(Words), !. word_spaces([]) --> []. word_spaces([""]) --> !. word_spaces([H|T]) --> { string_length(H, Len) }, [ w(H, Len, []) ], ( {T==[]} -> [] ; [b(1,_)], word_spaces(T) ). word_length(w(_,Len,_), Len). element_length(w(_,Len,_), Len). element_length(b(Len,_), Len). bullet_text(I, Bullet) :- integer(I), !, format(string(Bullet), '~d.', [I]). bullet_text(Bullet, Bullet).