guile macro indentation in emacs

Question

Is there something like (declare (indent defun)) for guile so indentation of user-defined macros works like defines?

For example, if I write the following macro,

(define-syntax my-when
  (syntax-rules ()
    ((my-when condition exp ...)
     (if condition
         (begin exp ...)))))

Then, I get indentation that looks like,

(my-when #t
         (write "hi"))

But would prefer the following

(my-when #t
  (write "hi"))

In elisp, I could get the desired indentation via

(defmacro my-when (condition &rest body)
  (declare (indent defun))
  `(if ,condition
       ,@body))

(my-when t
  (message "hi"))

Version/mode notes: emacs 26, scheme-mode w/ geiser, geiser-impl--implementation = guile

jpkotta jpkotta · Accepted Answer · 2017-05-15T17:10:25

Add an indent hint for the symbol:

(put 'my-when 'scheme-indent-function 1)

This is more or less what (declare (indent 1)) does in defmacro.

lisp-mode uses lisp-indent-line, which looks for the lisp-indent-function property on the symbol. The built-in scheme-mode uses lisp-indent-function, so you would think that it would work just like in lisp-mode. However the property name needs to match the mode name. See https://www.gnu.org/software/emacs/manual/html_node/elisp/Indenting-Macros.html#Indenting-Macros for the values of the property.

guile macro indentation in emacs

1 Answers