Questions tagged [boolean]

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why does this function return integers instead of `t` or `nil`

Why does this function print non-zero integers on non-empty lines? ;; taken from https://emacs.stackexchange.com/a/16826/10896 (defun current-line-empty-p () (interactive) (setq answer (string-...
4
votes
3answers
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What Emacs Lisp boolean/logical convenience functions exist?

What boolean/logical convenience functions / macros are available for Emacs Lisp in either the core set of functions or external packages? I'm interested in just about anything other than the built-...
7
votes
2answers
344 views

Understanding elisp idiom(boolean values vs. quoted arguments)?

I have some basic questions about elisp. I often see something like (search-forward "something" nil 'noerror) And sometimes I see something like (search-forward "something" nil :noerror) What is ...
8
votes
3answers
1k views

Quick way to toggle a variable

It would be nice to have a quick way to toggle a variable. Here's something that I have in mind. Call a "toggle var" function. The completing-read should list only variables that have single values (...