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3.3 @node Line Requirements ¶

Names used with @node have several requirements:

• All the node names in a single Texinfo file must be unique.

  This means, for example, that if you end every chapter with a summary, you must name each summary node differently. You cannot just call them all “Summary”. You may, however, duplicate the titles of chapters, sections, and the like. Thus you can end each chapter with a section called “Summary”, so long as the node names for those sections are all different.

  Node names, anchor names (see @anchor: Defining Arbitrary Cross-reference Targets), and float labels (see @float [type][,label]: Floating Material) must all be unique.

• Node names can contain @-commands³. For example, using @TeX{} in a node name results in the TeX logo being output, as it would be in normal text. Cross-references should use @TeX{} just as the node name does.

  Some commands do not make sense in node names; for instance, environments (e.g., @quotation), commands that read a whole line as their argument (e.g., @sp), and plenty of others. For the complete list of commands that are allowed, and their expansion for HTML identifiers and file names, see HTML Cross-reference Command Expansion.

• A node name may not start with a left parenthesis preceding a right parenthesis, as in (not)allowed, since this syntax is used to specify an external manual.
• Unfortunately, you cannot reliably use periods, commas, or colons within a node name; these can confuse some Info readers. texi2any quotes problematic node names and labels by default, but some Info readers do not recognize this syntax. Node name and label quoting causes DEL characters (‘CTRL-?’, character number 127, often rendered as ‘^?’) to appear around the name. To remove node names and labels quoting, you can set the customization variable INFO_SPECIAL_CHARS_QUOTE to ‘0’ (see Other Customization Variables).

  texi2any warns about such problematic usage in node names, menu items, and cross-references. If you don’t want to see the warnings, you can set the customization variable INFO_SPECIAL_CHARS_WARNING to ‘0’ (see Other Customization Variables).

  If you insist on using these characters in node names, in order not to confuse the Texinfo processors you must still escape those characters, by using either special insertions (see Inserting ‘,’ with @comma{}) or @asis (see @asis). For example:

  @node foo@asis{::}bar@comma{} baz
  

  As an example of avoiding the special characters, the following is a section title in this manual:

  @section @code{@@unnumbered}, @code{@@appendix}: Chapters with...
  

  But the corresponding node name lacks the commas and the subtitle:

  @node @code{@@unnumbered @@appendix}
  

• Case is significant in node names.
• Spaces before and after names on the ‘@node’ line are ignored. Multiple whitespace characters “inside” a name are collapsed to a single space. For example:

  @node foo bar
  @node  foo bar,
  @node foo bar ,
  @node foo  bar,
  @node  foo  bar ,
  

  all define the same node, namely ‘foo bar’. In menu entries, a single internal space should be used in node names or some versions of some Info readers will not find the node.