guix/build/emacs-utils.scm

   1 ;;; GNU Guix --- Functional package management for GNU
   2 ;;; Copyright © 2014 Mark H Weaver <mhw@netris.org>
   3 ;;;
   4 ;;; This file is part of GNU Guix.
   5 ;;;
   6 ;;; GNU Guix is free software; you can redistribute it and/or modify it
   7 ;;; under the terms of the GNU General Public License as published by
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   9 ;;; your option) any later version.
  10 ;;;
  11 ;;; GNU Guix is distributed in the hope that it will be useful, but
  12 ;;; WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;;; GNU General Public License for more details.
  15 ;;;
  16 ;;; You should have received a copy of the GNU General Public License
  17 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 (define-module (guix build emacs-utils)
  20   #:export (%emacs
  21             emacs-batch-eval
  22             emacs-batch-edit-file
  23             emacs-substitute-sexps
  24             emacs-substitute-variables))
  25
  26 ;;; Commentary:
  27 ;;;
  28 ;;; Tools to programmatically edit files using Emacs,
  29 ;;; e.g. to replace entire s-expressions in elisp files.
  30 ;;;
  31 ;;; Code:
  32
  33 (define %emacs
  34   ;; The `emacs' command.
  35   (make-parameter "emacs"))
  36
  37 (define (emacs-batch-eval expr)
  38   "Run Emacs in batch mode, and execute the elisp code EXPR."
  39   (unless (zero? (system* (%emacs) "--quick" "--batch"
  40                           (format #f "--eval=~S" expr)))
  41     (error "emacs-batch-eval failed!" expr)))
  42
  43 (define (emacs-batch-edit-file file expr)
  44   "Load FILE in Emacs using batch mode, and execute the elisp code EXPR."
  45   (unless (zero? (system* (%emacs) "--quick" "--batch"
  46                           (string-append "--visit=" file)
  47                           (format #f "--eval=~S" expr)))
  48     (error "emacs-batch-edit-file failed!" file expr)))
  49
  50 (define-syntax emacs-substitute-sexps
  51   (syntax-rules ()
  52     "Substitute the S-expression immediately following the first occurrence of
  53 LEADING-REGEXP by the string returned by REPLACEMENT in FILE.  For example:
  54
  55   (emacs-substitute-sexps \"w3m.el\"
  56     (\"defcustom w3m-command\"
  57      (string-append w3m \"/bin/w3m\"))
  58     (\"defvar w3m-image-viewer\"
  59      (string-append imagemagick \"/bin/display\")))
  60
  61 This replaces the default values of the `w3m-command' and `w3m-image-viewer'
  62 variables declared in `w3m.el' with the results of the `string-append' calls
  63 above.  Note that LEADING-REGEXP uses Emacs regexp syntax."
  64     ((emacs-substitute-sexps file (leading-regexp replacement) ...)
  65      (emacs-batch-edit-file file
  66        `(progn (progn (goto-char (point-min))
  67                       (re-search-forward ,leading-regexp)
  68                       (kill-sexp)
  69                       (insert " ")
  70                       (insert ,(format #f "~S" replacement)))
  71                ...
  72                (basic-save-buffer))))))
  73
  74 (define-syntax emacs-substitute-variables
  75   (syntax-rules ()
  76     "Substitute the default value of VARIABLE by the string returned by
  77 REPLACEMENT in FILE.  For example:
  78
  79   (emacs-substitute-variables \"w3m.el\"
  80     (\"w3m-command\" (string-append w3m \"/bin/w3m\"))
  81     (\"w3m-image-viewer\" (string-append imagemagick \"/bin/display\")))
  82
  83 This replaces the default values of the `w3m-command' and `w3m-image-viewer'
  84 variables declared in `w3m.el' with the results of the `string-append' calls
  85 above."
  86     ((emacs-substitute-variables file (variable replacement) ...)
  87      (emacs-substitute-sexps file
  88        ((string-append "(def[a-z]+[[:space:]\n]+" variable "\\>")
  89         replacement)
  90        ...))))
  91
  92 ;;; emacs-utils.scm ends here