1.9 General Syntactic Conventions

This section describes the general conventions used in all Texinfo documents.

• All printable ASCII characters except ‘@’, ‘{’ and ‘}’ can appear in a Texinfo file and stand for themselves. ‘@’ is the escape character which introduces commands, while ‘{’ and ‘}’ are used to surround arguments to certain commands. To put one of these special characters into the document, put an ‘@’ character in front of it, like this: ‘@@’, ‘@{’, and ‘@}’.
• Texinfo supports the usual quotation marks used in English and in other languages; see Inserting Quotation Marks.
• Use three hyphens in a row, ‘---’, to produce a long dash—like this (called an em dash), used for punctuation in sentences. Use two hyphens, ‘--’, to produce a medium dash (called an en dash), used primarily for numeric ranges, as in “June 25–26”. Use a single hyphen, ‘-’, to produce a standard hyphen used in compound words. For display on the screen, Info reduces three hyphens to two and two hyphens to one (not transitively!). Of course, any number of hyphens in the source remain as they are in literal contexts, such as @code and @example.
• Form feed (CTRL-l) characters in the input are handled as follows:

  PDF/DVI

  In normal text, treated as ending any open paragraph; essentially ignored between paragraphs.

  Info

  Output as-is between paragraphs (their most common use); in other contexts, they may be treated as regular spaces (and thus consolidated with surrounding whitespace).

  HTML

  Written as a numeric entity except contexts where spaces are ignored; for example, in ‘@footnote{ ^L foo}’, the form feed is ignored.

  XML

  Keep them everywhere; in attributes, escaped as ‘\f’; also, ‘\’ is escaped as ‘\\’ and newline as ‘\n’.

  Docbook

  Completely removed, as they are not allowed.

  As you can see, because of these differing requirements of the output formats, it’s not possible to use form feeds completely portably.

• Caution: Last, do not use tab characters in a Texinfo file! (Except perhaps in verbatim modes.) TeX uses variable-width fonts, which means that it is impractical at best to define a tab to work in all circumstances. Consequently, TeX treats tabs like single spaces, and that is not what they look like in the source. Furthermore, makeinfo does nothing special with tabs, and thus a tab character in your input file will usually have a different appearance in the output.

  To avoid this problem, Texinfo mode in GNU Emacs inserts multiple spaces when you press the TAB key. Also, you can run untabify in Emacs to convert tabs in a region to multiple spaces, or use the unexpand command from the shell.