GNU bug report logs - #3101
23.0.92; Emacs manual, node Tags

Previous Next

Full log

Message #14 received at 3101-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 3101-done <at> debbugs.gnu.org
Subject: Re: bug#3101: 23.0.92; Emacs manual, node Tags
Date: Sun, 26 Apr 2009 21:06:52 +0300

> From: "Drew Adams" <drew.adams <at> oracle.com>
> Cc: <3101-done <at> emacsbugs.donarmstrong.com>
> Date: Sat, 25 Apr 2009 14:56:09 -0700
> 
> > Next attempt:
> > 
> >     A @dfn{tag} is a named subunit of a program or of a document.  In
> >   program source code, tags are syntactic elements of the program:
> >   functions, subroutines, data types, macros, etc.  In a 
> >   document, tags are chapters, sections, appendices, etc.
> 
> Sounds good. I tend to think of them as *definitions* of functions,
> subroutines... Dunno if that helps.

Let's try this one:

    A @dfn{tag} is a reference to a subunit in a program or in a
  document.  In program source code, tags reference syntactic elements
  of the program: functions, subroutines, data types, macros, etc.  In a
  document, tags reference chapters, sections, appendices, etc.  Each
  tag specifies the file name on which the corresponding subunit is
  defined, and the position of the subunit's definition in that file.

    A @dfn{tags table} records the tags extracted by scanning the source
  code of a certain program or a certain document.  Tags extracted from
  generated files reference subunits in the original files, rather than
  the generated files that were scanned during tag extraction.  Examples
  of generated files include C files generated from Cweb source files,
  from a Yacc parser, or from Lex scanner definitions; @file{.i}
  preprocessed C files; and Fortran files produced by preprocessing
  @file{.fpp} source files.

    To produce tags tables, you use the @samp{etags} command, submitting
  it a document or the source code of a program.  @samp{etags} writes
  the tags to files called @dfn{tags table files}, or @dfn{tags file} in
  short.  The conventional name for a tags file is @file{TAGS}.

    Emacs uses the information recorded in tags tables in commands that
  search or replace through multiple source files: these commands use
  the names of the source files recorded in the tags table to know which
  files to search.  Other commands, such as @kbd{M-.}, which finds the
  definition of a function, use the recorded information about the
  function names and positions to find the source file and the position
  within that file where the function is defined.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.