basic docs about buildsystem classes

diff --git a/doc/PROGRAMMING b/doc/PROGRAMMING
index 9963181ea7998fdf20acce05ced6f233da81d0e3..f1bc7a0de72f52d6adfff392114b14356de7c1b8 100644 (file)
--- a/doc/PROGRAMMING
+++ b/doc/PROGRAMMING
@@ -250,13 +250,13 @@ write_log($cmd, $package ...)
        Writes the log files for the specified package(s), adding
        the cmd to the end.
 
-Sequence Addons
+Sequence Addons:
 ---------------
 
 The dh(1) command has a --with <addon> parameter that ca be used to load
-a sequence addon named Debian::Debhelper::Sequence::<addon>. 
-These addons can add/remove commands to the dh command sequences, by calling
-some functions from Dh_Lib:
+a sequence addon module named Debian::Debhelper::Sequence::<addon>. 
+These modules can add/remove commands to the dh command sequences, by
+calling some functions from Dh_Lib:
 
 insert_before($existing_command, $new_command)
        Insert $new_command in sequences before $existing_command
@@ -267,4 +267,16 @@ insert_after($existing_command, $new_command)
 remove_command($existing_command)
        Remove $existing_command from the list of commands to run.
 
+Buildsystem Classes:
+-------------------
+
+The dh_auto_* commands are frontends that use debhelper buildsystem
+classes. These classes have names like Debian::Debhelper::Buildsystem::foo,
+and are derived from Debian::Debhelper::Buildsystem, or other, related
+classes.
+
+A buildsystem class needs to inherit or define these methods: DESCRIPTION,
+check_auto_buildable, build, test, install, clean. See the comments
+inside Debian::Debhelper::Buildsystem for details.
+
 -- Joey Hess <joeyh@debian.org>