description = "Cedit and paredit for structural editing"
title = "Cedit and Paredit"
date = 2014-08-04T07:10:14Z
tags = ["development", "emacs"]
I recently discovered [cedit], which provides some structural
commands for editing c-like languages. (See this
[Emacs Rocks! episode][e14] if you're not familiar with the concept:
it introduces [paredit], a structural editing mode for lisps).
So, it deals with curly braces and semicolons, keeping things balanced
and correct as show in its [screencast][cedit-readme]. It mentions that it
integrates with [paredit] rather than duplicating *all* its
functionality. After setting up cedit, I decided to try enabling
paredit alongside cedit and disabling autopair. Once I did,
however, I noticed an annoying formatting issue: If I were to type
`foo` and then `(`, paredit would format this as `foo ()`, which makes
sense, considering that paredit is written for lisps — s-expressions
are usually separated by spaces — but not so much for c-like languages.
I was thinking about disabling paredit and going back to autopair,
when I decided to look through the configuration variables for
paredit. Turns out it provides
`paredit-space-for-delimiter-predicates`, which is a list of functions
that control whether a space should be inserted. So, solving the
formatting issue turned out to be pretty simple:
(defun ap/cedit-space-delimiter-p (endp delimiter)
"Don't insert a space before delimiters in c-style modes"
(add-to-list 'paredit-space-for-delimiter-predicates #'ap/cedit-space-delimiter-p)
Hopefully that saves someone some time if they try to use the two