Editing Lightweight markup language (section)

==== Underlined headings ====
<pre>Level 1 Heading
===============

Level 2 Heading
---------------

Level 3 Heading
~~~~~~~~~~~~~~~</pre>
The first style uses underlines, i.e. repeated characters (e.g. equals <code>=</code>, hyphen <code>-</code> or tilde <code>~</code>, usually at least two or four times) in the line below the heading text.

{| class="wikitable sortable"
|+ Underlined heading levels
! {{diagonal split header|Language|Character}}
! <code><nowiki>=</nowiki></code>
! <code><nowiki>-</nowiki></code>
! <code><nowiki>~</nowiki></code>
! <code><nowiki>*</nowiki></code>
! <code><nowiki>#</nowiki></code>
! <code><nowiki>+</nowiki></code>
! <code><nowiki>^</nowiki></code>
! <code><nowiki>_</nowiki></code>
! <code><nowiki>:</nowiki></code>
! <code><nowiki>"</nowiki></code>
! <code><nowiki>'</nowiki></code>
! <code><nowiki>`</nowiki></code>
! <code><nowiki>.</nowiki></code>
!title="Minimum of characters"| Min. length
<!--! mix-->
|-
! {{rh}} | [[AsciiDoc]]{{efn|name=asciidoctor-deprecation}}
| {{yes-no|1}} || {{yes-no|2}} || {{yes-no|3}} || {{no}} || {{no}} || {{yes-no|5}} || {{yes-no|4}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || 2{{efn|Width of title ± 2 characters|group=asciidoc}}
|-
! {{rh}} | [[Markdown]]
| {{yes|1}} || {{yes|2}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || 1
|-
! {{rh}} | [[reStructuredText]]
| colspan="13" {{yes|Heading structure is determined dynamically from the succession of headings}}  || ''heading width''
|-
! {{rh}} | [[Setext]]
| {{yes|1}} || {{yes|2}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{dunno}}
|-
! {{rh}} | [[Texy!]]
| {{yes|3}} || {{yes|4}} || {{no}} || {{yes|2}} || {{yes|1}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || {{no}} || 3
|-
|}

Headings may optionally be overline in [[reStructuredText]], in addition to being underlined.