Elisp Notes

  • Truthy Values

'() and nil are false. Anything and everything else is true.

t is preferred way to represent true.

  • TDD in Elisp

ERT is a tool that comes with emacs to do automated unit testing of elisp functions

  • Characters

Characters are simply the integers representing the ascii codes. Character literals are represented as a question mark followed by the character. So, for example, ?a evaluates to 97.

It's a good idea to escape punctuation characters with `‘ to avoid confusion. For example, both ?/ and ?\/ eval to 47

Control characters (like tab, backspace, etc) are represented using `‘ followed by a lowercase letter.

  • progn

Use progn it to run multiple expressions and return last expression.