[slime-devel] [patch] a way to specify custom Emacs indentation right in the Lisp source

[Matthias Koeppe]

Michael Livshin <gmane at cmm.kakpryg.net> writes:

> the attached patch adds a way to define and access custom indentation
> specifications like this:
>
> <example>
> (defmacro my-macro (name (&rest args) &body function-bindings)
>   ...)
>
> #+swank
> (setf (swank:emacs-indentation 'my-macro)
>       '(6 4 (&whole 2 &rest (&whole 1 &lambda &body))))
> </example>

I am also interested in a feature like this.

In my opinion, an important consideration in implementing it is that
FASL files generated within SLIME should still be loadable into
non-SWANK images.

I am using the following code to do that (for a different customization):

;; Arrange for SLIME to use the right readtable
(when (find-package :swank)
  (push (cons :guile guile-internal::*guile-readtable*)
        (symbol-value (intern (symbol-name '#:*readtable-alist*) 
                              :swank)))

  (defmethod swank-backend:swank-compile-file :around (file-name load-p)
    (if (string= (pathname-type file-name) "scm")
        (let ((*package* (find-package :guile))
              (*readtable* guile-internal::*guile-readtable*))
          (call-next-method))
        (call-next-method)))
)

Because all references to the SWANK package are made at load time (not
read or compile time), FASL files including the above code can still
be loaded into non-SWANK images.

A SWANK macro (SWANK:DEF-EMACS-INDENTATION?) that expands into
something similar would be useful.

Matthias
-- 
Matthias Köppe -- http://www.math.uni-magdeburg.de/~mkoeppe
(currently @math.ucdavis.edu)