Add short chapter in developer's guide on formatting source code.

doc/src/sgml/sources.sgml

@@ -0,0 +1,76 @@
+ <chapter>
+  <title>Postgres Source Code</title>
+
+  <sect1>
+   <title>Formatting</title>
+
+   <para>
+    Source code formatting uses a 4 column tab spacing, currently with 
+    tabs preserved (i.e. tabs are not expanded to spaces).
+   </para>
+
+   <para>
+    For emacs, add the following (or something similar)
+    to your <filename>~/.emacs</filename> 
+    initialization file:
+
+    <programlisting>
+;; check for files with a path containing "postgres" or "pgsql"
+(setq auto-mode-alist (cons '("\\(postgres\\|pgsql\\).*\\.[ch]\\'" . pgsql-c-mode) auto-mode-alist))
+(setq auto-mode-alist (cons '("\\(postgres\\|pgsql\\).*\\.cc\\'" . pgsql-c-mode) auto-mode-alist))
+
+(defun pgsql-c-mode ()
+  ;; sets up formatting for Postgres C code
+  (interactive)
+  (c-mode)
+  (setq-default tab-width 4)
+  (c-set-style "bsd")             ; set c-basic-offset to 4, plus other stuff
+  (c-set-offset 'case-label '+)   ; tweak case indent to match PG custom
+  (setq indent-tabs-mode t))      ; make sure we keep tabs when indenting
+    </programlisting>
+   </para>
+
+   <para>
+    For <application>vi</application>, your
+    <filename>~/.vimrc</filename> or equivalent file should contain
+    the following:
+
+    <programlisting>
+set tabstop=4
+    </programlisting>
+
+    or equivalently from within vi, try
+
+    <programlisting>
+:set ts=4
+    </programlisting>
+   </para>
+
+   <para>
+    The text browsing tools <application>more</application> and
+    <application>less</application> can be invoked as
+
+    <programlisting>
+more -x4
+less -x4
+    </programlisting>
+   </para>
+  </sect1>
+ </chapter>
+
+<!-- Keep this comment at the end of the file
+Local variables:
+mode:sgml
+sgml-omittag:nil
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
+sgml-indent-data:t
+sgml-parent-document:nil
+sgml-default-dtd-file:"./reference.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:("/usr/lib/sgml/CATALOG")
+sgml-local-ecat-files:nil
+End:
+-->