is traditionally presented in typewriter-like fonts where each character occupies the same fixed width. HTML offers the semantic <code> and the deprecated, presentational <tt> element types for this task. Mediawiki and Gemtext do not provide lightweight markup for inline code spans. Heading syntax Headings are usually available in up to six levels, but the top one is often reserved to contain the same as the document title, which may be set externally. Some documentation may associate levels with divisional types, e.g. part, chapter, section, article or paragraph. Most LMLs follow one of two styles for headings, either Setext-like underlines or atx-like line markers, or they support both. Underlined headings Level 1 Heading =============== Level 2 Heading --------------- Level 3 Heading ~~~~~~~~~~~~~~~ The first style uses underlines, i.e. repeated characters (e.g. equals =, hyphen - or tilde ~, usually at least two or four times) in the line below the heading text. RST determines heading levels dynamically, which makes authoring more individual on the one hand, but complicates merges from external sources on the other hand. Prefixed headings # Level 1 Heading ## Level 2 Heading ## ### Level 3 Heading ### The second style is based on repeated markers (e.g. hash #, equals = or asterisk *) at the start of the heading itself, where the number of repetitions indicates the (sometimes inverse) heading level. Most languages also support the reduplication of the markers at the end of the line, but whereas some make them mandatory, others do not even expect their numbers to match. Org-mode supports indentation as a means of indicating the level. BBCode does not support section headings at all. POD and Textile choose the HTML convention of numbered heading levels instead. Microsoft Word supports auto-formatting paragraphs as headings if they do not contain more than a handful of words, no period at the end and the user hits the enter key twice. For lower levels, the user may press the tabulator key the according number of times before entering the text, i.e. one through eight tabs for heading levels two through nine. Link syntax Hyperlinks can either be added inline, which may clutter the code because of long URLs, or with named alias or numbered id references to lines containing nothing but the address and related attributes and often may be located anywhere in the document. Most languages allow the author to specify text Text to