CODEWITHSUNDEEP
regexemacs
iainH
iainH

Reputation: 1084

how do I define an emacs replace-regex shortcut command?

I don't understand how to re-use an interactive command in a command I'm writing myself.

I want to make a command that always uses the same arguments to replace-regexp. It's a shortcut, really.

So I tried to mimic in a function what I'd done interactively on a selected region, namely:

M-x replace-regexp  RET ^\(\s *\)\(.*\)\s *$  RET  \1 + '\2'

I mimicked it by writing this function:

(defun myH2js ()
  "Converts html to an (incomplete) JavaScript String concatenation."

  (interactive)
  (let (p1 p2)
    (setq p1 "^\(\s *\)\(.*\)\s *$" )
    (setq p2 "\1 + '\2'" )
    (replace-regexp  p1 p2 )
  )
)

But my function "replaces zero occurrences" of the selected region whereas my interaction rewrites everything exactly as I want.

What am I doing wrong?

Upvotes: 1

Views: 338

Answers (1)

Barmar
Barmar

Reputation: 781210

You need to double the backslashes in the strings, because backslash is both the string and regular expression escape character:

(defun myH2js (start end)
  "Converts html to an (incomplete) JavaScript String concatenation."

  (interactive "r")
  (let ((p1 "^\\(\\s *\\)\\(.*\\)\\s *$")
        (p2 "\\1 + '\\2'"))
    (replace-regexp p1 p2 nil start end)
  )
)

Note that replace-regexp is not recommended for use inside programs; the online documentation says:

This function is usually the wrong thing to use in a Lisp program. What you probably want is a loop like this:

  (while (re-search-forward regexp nil t)
    (replace-match to-string nil nil))

which will run faster and will not set the mark or print anything.

Upvotes: 1

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