## Chapter 44. PostgreSQL Coding Conventions

## 44.1. Formatting

Source code formatting uses 4 column tab spacing, with tabs preserved (i.e. tabs are not expanded to spaces). Each logical indentation level is one additional tab stop. Layout rules (brace positioning, etc) follow BSD conventions.

While submitted patches do not absolutely have to follow these formatting rules, it's a good idea to do so. Your code will get run through pgindent, so there's no point in making it look nice under some other set of formatting conventions.

For Emacs, add the following (or something similar) to your `~/.emacs` initialization file:

    ;; 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 PostgreSQL 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

For vi, your `~/.vimrc` or equivalent file should contain the following:

    set tabstop=4

or equivalently from within vi, try

    :set ts=4

The text browsing tools more and less can be invoked as

    more -x4
    less -x4

to make them show tabs appropriately.