@Section
   @Tag { sections }
   @Title { Sections }
@Begin
@PP
The DocumentLayout package provides sections, like this:
@ID @Code {
"some introductory text."
"@BeginSections"
"@Section"
"    @Title { Introduction }"
"@Begin"
"@PP"
"..."
"..."
"@End @Section"
"@Section"
"    @Title { Displays and lists }"
"@Begin"
"@PP"
"..."
"..."
"@End @Section"
"@EndSections"
}
@Code "@BeginSections" and @Code "@EndSections" symbols must
bracket the sections, and paragraph symbols are needed at the
beginning of each section but not before or after the whole group.  The
@Code "@Title" option of @Code "@Section" is made into a numbered heading,
like those in the present document, preceded by a conditional new page
symbol (Section {@NumberOf cnp}).  The body of each section is enclosed in
@Code "@Begin" and {@Code "@End @Section"}, although @Code "{" and @Code "}"
are sufficient if preferred.  The former are more long-winded but less
prone to error.
@PP
Within sections one may choose to have a sequence of subsections.  These
are introduced by @Code "@BeginSubSections" and concluded by
{@Code "@EndSubSections"}:
@ID @Code {
"in the following subsections."
"@BeginSubSections"
"@SubSection"
"    @Title { ... }"
"@Begin"
"@PP"
"..."
"@End @SubSection"
"@SubSection"
"    @Title { ... }"
"@Begin"
"@PP"
"..."
"@End @SubSection"
"@EndSubSections"
}
The first subsection of the first section will be numbered 1.1, and so
on.  There are no sub-subsections.  DocumentLayout also provides appendices
in an exactly analogous way, using the symbols {@Code "@BeginAppendices"},
{@Code "@Appendix"}, and {@Code "@EndAppendices"}, and subappendices
within any appendix using the symbols {@Code "@BeginSubAppendices"},
{@Code "@SubAppendix"}, and {@Code "@EndSubAppendices"}.
@End @Section
