[PATCH] vcs-to-changelog: Add manual documentation

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

	* doc/vcs-to-changelog.texi: New file.
	* doc/gnulib.texi (Build Infrastructure Modules): Add
	vcs-to-changelog section.
---
 doc/gnulib.texi           |  3 +++
 doc/vcs-to-changelog.texi | 52 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 doc/vcs-to-changelog.texi

diff --git a/doc/gnulib.texi b/doc/gnulib.texi
index c62b20d75..b673189a1 100644
--- a/doc/gnulib.texi
+++ b/doc/gnulib.texi
@@ -6761,6 +6761,7 @@ for use with GNU Automake (in particular).
 * configmake::
 * warnings::
 * manywarnings::
+* VCS To ChangeLog::
 @end menu
 
 @include havelib.texi
@@ -6777,6 +6778,8 @@ for use with GNU Automake (in particular).
 
 @include manywarnings.texi
 
+@include vcs-to-changelog.texi
+
 
 @node Build Infrastructure Files
 @chapter Build Infrastructure Files
diff --git a/doc/vcs-to-changelog.texi b/doc/vcs-to-changelog.texi
new file mode 100644
index 000000000..060f00bd5
--- /dev/null
+++ b/doc/vcs-to-changelog.texi
@@ -0,0 +1,52 @@
+@node VCS To ChangeLog
+@section VCS To ChangeLog
+
+@c Copyright (C) 2020 Free Software Foundation, Inc.
+
+@c Permission is granted to copy, distribute and/or modify this document
+@c under the terms of the GNU Free Documentation License, Version 1.3 or
+@c any later version published by the Free Software Foundation; with no
+@c Invariant Sections, no Front-Cover Texts, and no Back-Cover
+@c Texts.  A copy of the license is included in the ``GNU Free
+@c Documentation License'' file as part of this distribution.
+
+@cindex VCS To ChangeLog
+@findex vcs-to-changelog
+
+Gnulib provides the @samp{vcs-to-changelog} module to generate an output
+similar to the GNU ChangeLog format from metadata of source control software
+such as git.  Here's an example of using @samp{vcs-to-changelog}:
+
+@example
+build-aux/vcs_to_changelog.py <from_ref> <to_ref>
+@end example
+
+where @code{<from_ref>} and @code{<to_ref>} refer to the range of commits to
+generate the output.
+
+VCS To ChangeLog currently recognises changes in C source code and can traverse
+commits in git.  Additional source frontends and source control backends may be
+added to the module. @samp{vcs-to-changelog} takes the following optional
+arguments:
+
+@itemize
+@item @code{-d}: Run the parser debugger, used for debugging
+@samp{vcs-to-changelog}
+@item @code{-q filename}: Load @var{filename} as the quirks file for the
+project.
+@end itemize
+
+The quirks file is a python module that must minimally implement a
+@code{get_project_quirks} function that returns an object of type
+@code{ProjectQuirks} or its subclass.  The subclass may override the following
+members of @code{ProjectQuirks}:
+
+@itemize @bullet
+@item @code{repo}: Specify the project repo source control.  The default value
+is @code{git}.
+@item @code{IGNORE_LIST}: A list of files to ignore in the changesets.
+@item @code{MACRO_QUIRKS}: A list of dictionary entries with indexes as
+@code{orig} and @code{sub} where @code{orig} is a Python regular expression
+pattern to match and @code{sub} is the substitution.
+@item @code{C_MACROS}: A list of C preprocessor macro definitions.
+@end itemize
-- 
2.24.1