#[
A paragraph is a document-structural object, like a section or a table of
contents, and making paragraphs is a service @document provides: inside a
@document, blank-line-separated text becomes paragraphs (the LaTeX
convention) and @par need not be written.  @par is the explicit form, for
a text FRAGMENT rendered without a @document, where nothing infers them.
Written inside a @document it is harmless: html sees a <p>, which the
paragraph pass recognizes as a block and leaves alone, and \par in
vertical mode is a no-op.
]#

@@par.k s : A paragraph of text @@
@@par.html :: <p>*s*</p> @@
@@par.tex ::
\par
*s*
\par
@@
# In plain text a paragraph is delimited by blank lines, which
# phases.justify_blocks then fills; #/2 inserts them without depending on
# the definition body's own whitespace surviving extraction.
@@par.txt :: #/2*s*#/2 @@

@@sp.k : Non-breaking space character @@
@@sp.html :: &^#160; @@
@@sp.tex :: ~ @@

# TODO: Easy in LaTeX; how to handle in HTML and plain text?
# @@footnote.k s : Footnote (TBD) @@
# @@footnote :: [*s*] @@

@@indent.k s :w.int 3 :linebreak.bool false : Indented block @@
@@indent.html,tex,txt :: @eval block.Indent(K) eval@ @@

@@quote.k s :w.int 1 :source : Quotation block @@

@@quote.html ::
<div class="quote">
*s*
</div>
@@

@@quote.tex ::
\quoteblock{*s*}{*source*}
@@

@@quote.txt ::
  @eval block.block_indent(K) eval@
@@

@@note.k s :label Note :color 1.0,1.0,0.9 :bordercolor 0.2,0.2,0.2 :level.int 0 :width
  : Rectangular block for a special note @@

@@note.html,tex :: @eval block.Note(K) eval@ @@

@@center.k s : Center text @@

@@center.tex ::
\begin{center}
*s*
\end{center}
@@

@@center.html ::
<div class="center">
*s*
</div>
@@

@@right.k s :  Right-justified text @@

@@right.html ::
<b>TBD</b> *s*
@@

@@right.tex ::
\begin{flushright}
*s*
\end{flushright}
@@

@@nl.k : Newline character @@
@@nl.html :: <br> @@
@@nl.tex :: \newline @@
@@nl.txt :: \n @@

@@newpage.k : Start new page @@
@@newpage.html :: @@
@@newpage.tex :: \newpage @@
@@newpage.txt :: @@

@@extendpage.k linecount : Extenad current page @@
@@extendpage.html :: @@
@@extendpage.tex :: \enlargethispage{*linecount*\baselineskip} @@
@@extendpage.txt :: @@

@@vspace.k lines.float : Vertical space, in multiples of the current line height @@
@@vspace.tex :: \vspace{*lines*\baselineskip} @@
@@vspace.html :: <div style="height: *lines*lh"></div> @@
@@vspace.txt :: @eval "__VSPACE__" * round(*lines*) @ @@

@@vfill.k :
Fill the vertical space so that any following text is flush with the bottom
of the page (in HTML, the bottom of the window; once the content is taller
than the window the space collapses, as on a full LaTeX page).  Several
vfills divide the space equally, like LaTeX's \vfill glue.  In plain text,
only makes some vertical space. @@
@@vfill.tex :: \vfill @@
# An empty glue div; block.css gives it flex-grow 1 and makes the text
# column a flex column only in documents that use it (the :has() rule).
@@vfill.html :: <div class="vfill"></div> @@
@@vfill.txt :: @vspace 3 @ @@


@@qa.k question | answer : Question and answer formatting @@
@@qa.html,tex,txt ::
@b Q: @ *question*

@b A: @ *answer*
@@

@@@argtype coords | x and y coordinates :pattern 'float'\s+'float' @@@

@@block.k : to.coords | content :width.float .5 :point.coords 0.0 0.0
: Absolute positioning of text block @@

@@block.tex :: @eval block.Block(K) eval@ @@

@@lines.k s : Maintain line breaks @@
@@lines.html,tex,txt :: @eval block.Lines(K) eval@ @@

@@twocolumns.k s : Format *s* in two columns @@
@@twocolumns.tex ::
\begin{multicols}{2}
*s*
\end{multicols}
@@

@@left_right.k left | right : Text left- and right- justified on one line @@

@@left_right.tex ::
  \makebox[\dimexpr\linewidth+\labelindent\relax]{*left*\hfill *right*}
@@