Source File Tag Syntax

• In Lisp code, any function defined with defun, any variable defined with defvar or defconst, and in general the first argument of any expression that starts with `(def' in column zero, is a tag.
• In Scheme code, tags include anything defined with def or with a construct whose name starts with `def'. They also include variables set with set! at top level in the file.
• In C code, any C function or typedef is a tag, and so are definitions of struct, union and enum. Any #define is also a tag, unless `--no-defines' is specified when the tags table is constructed, which sometimes makes the tags file much smaller. In C++ code, member functions are also recognized.
• In Yacc or Bison input files, each rule defines as a tag the nonterminal it constructs. The portions of the file that contain C code are parsed as C code.
• In Fortran code, functions and subroutines are tags.
• In Pascal code, the tags are the functions and procedures defined in the file.
• In Perl code, the tags are the procedures defined by the sub keyword.
• In Prolog code, a tag name appears at the left margin.
• In Erlang code, the tags are the functions, records, and macros defined in the file.
• In assembler code, labels appearing at the beginning of a line, followed by a colon, are tags.
• In LaTeX text, the argument of any of the commands \chapter, \section, \subsection, \subsubsection, \eqno, \label, \ref, \cite, \bibitem, \part, \appendix, \entry, or \index, is a tag. Other commands can make tags as well, if you specify them in the environment variable TEXTAGS before invoking etags. The value of this environment variable should be a colon-separated list of commands names. For example,

  TEXTAGS="def:newcommand:newenvironment"
  export TEXTAGS
  

  specifies (using Bourne shell syntax) that the commands `\def', `\newcommand' and `\newenvironment' also define tags.
• You can also generate tags based on regexp matching (see section Creating Tags Tables) for any text file.