31.3 Indentation for Programs

The best way to keep a program properly indented is to use Emacs to reindent it as you change it. Emacs has commands to indent properly either a single line, a specified number of lines, or all of the lines inside a single parenthetical grouping.

• Basic Indent: Indenting a single line.
• Multi-line Indent: Commands to reindent many lines at once.
• Lisp Indent: Specifying how each Lisp function should be indented.
• C Indent: Extra features for indenting C and related modes.
• Custom C Indent: Controlling indentation style for C and related modes.

Emacs also provides a Lisp pretty-printer in the library pp. This program reformats a Lisp object with indentation chosen to look nice.