aboutsummaryrefslogtreecommitdiff
path: root/emacs/guix-backend.el
blob: a320eae35acf5f63c619613e7e35b1c531c67982 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
;;; guix-backend.el --- Communication with Geiser

;; Copyright © 2014 Alex Kost <alezost@gmail.com>

;; This file is part of GNU Guix.

;; GNU Guix is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Guix is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This file provides the code for interacting with Guile using Geiser.

;; By default (if `guix-use-guile-server' is non-nil) 2 Geiser REPLs are
;; started.  The main one (with "guile --listen" process) is used for
;; "interacting" with a user - for showing a progress of
;; installing/deleting Guix packages.  The second (internal) REPL is
;; used for synchronous evaluating, e.g. when information about
;; packages/generations should be received for a list/info buffer.
;;
;; This "2 REPLs concept" makes it possible to have a running process of
;; installing/deleting packages and to continue to search/list/get info
;; about other packages at the same time.  If you prefer to use a single
;; Guix REPL, do not try to receive any information while there is a
;; running code in the REPL (see
;; <https://github.com/jaor/geiser/issues/28>).
;;
;; If you need to use "guix.el" in another Emacs (i.e. when there is
;; a runnig "guile --listen..." REPL somewhere), you can either change
;; `guix-default-port' in that Emacs instance or set
;; `guix-use-guile-server' to t.
;;
;; Guix REPLs (unlike the usual Geiser REPLs) are not added to
;; `geiser-repl--repls' variable, and thus cannot be used for evaluating
;; while editing scm-files.  The only purpose of Guix REPLs is to be an
;; intermediate between "Guix/Guile level" and "Emacs interface level".
;; That being said you can still want to use a Guix REPL while hacking
;; auxiliary scheme-files for "guix.el".  You can just use "M-x
;; connect-to-guile" (connect to "localhost" and `guix-default-port') to
;; have a usual Geiser REPL with all stuff defined by "guix.el" package.

;;; Code:

(require 'geiser-mode)

(defvar guix-load-path
  (file-name-directory (or load-file-name
                           (locate-library "guix")))
  "Directory with scheme files for \"guix.el\" package.")

(defvar guix-helper-file
  (expand-file-name "guix-helper.scm" guix-load-path)
  "Auxiliary scheme file for loading.")

(defvar guix-guile-program (or geiser-guile-binary "guile")
  "Name of the guile executable used for Guix REPL.
May be either a string (the name of the executable) or a list of
strings of the form:

  (NAME . ARGS)

Where ARGS is a list of arguments to the guile program.")


;;; REPL

(defgroup guix-repl nil
  "Settings for Guix REPLs."
  :prefix "guix-repl-"
  :group 'guix)

(defcustom guix-repl-startup-time 30000
  "Time, in milliseconds, to wait for Guix REPL to startup.
Same as `geiser-repl-startup-time' but is used for Guix REPL.
If you have a slow system, try to increase this time."
  :type 'integer
  :group 'guix-repl)

(defcustom guix-repl-buffer-name "*Guix REPL*"
  "Default name of a Geiser REPL buffer used for Guix."
  :type 'string
  :group 'guix-repl)

(defcustom guix-after-start-repl-hook ()
  "Hook called after Guix REPL is started."
  :type 'hook
  :group 'guix-repl)

(defcustom guix-use-guile-server t
  "If non-nil, start guile with '--listen' argument.
This allows to receive information about packages using an additional
REPL while some packages are being installed/removed in the main REPL."
  :type 'boolean
  :group 'guix-repl)

(defcustom guix-default-port 37246
  "Default port used if `guix-use-guile-server' is non-nil."
  :type 'integer
  :group 'guix-repl)

(defvar guix-repl-buffer nil
  "Main Geiser REPL buffer used for communicating with Guix.
This REPL is used for processing package actions and for
receiving information if `guix-use-guile-server' is nil.")

(defvar guix-internal-repl-buffer nil
  "Additional Geiser REPL buffer used for communicating with Guix.
This REPL is used for receiving information only if
`guix-use-guile-server' is non-nil.")

(defvar guix-internal-repl-buffer-name "*Guix Internal REPL*"
  "Default name of an internal Guix REPL buffer.")

(defvar guix-before-repl-operation-hook nil
  "Hook run before executing an operation in Guix REPL.")

(defvar guix-after-repl-operation-hook
  '(guix-repl-operation-success-message)
  "Hook run after executing successful operation in Guix REPL.")

(defvar guix-repl-operation-p nil
  "Non-nil, if current operation is performed by `guix-eval-in-repl'.
This internal variable is used to distinguish Guix operations
from operations performed in Guix REPL by a user.")

(defvar guix-repl-operation-type nil
  "Type of the current operation performed by `guix-eval-in-repl'.
This internal variable is used to define what actions should be
executed after the current operation succeeds.
See `guix-eval-in-repl' for details.")

(defun guix-repl-operation-success-message ()
  "Message telling about successful Guix operation."
  (message "Guix operation has been performed."))

(defun guix-get-guile-program (&optional internal)
  "Return a value suitable for `geiser-guile-binary'."
  (if (or internal
          (not guix-use-guile-server))
      guix-guile-program
    (append (if (listp guix-guile-program)
                guix-guile-program
              (list guix-guile-program))
            ;; Guile understands "--listen=..." but not "--listen ..."
            (list (concat "--listen="
                          (number-to-string guix-default-port))))))

(defun guix-start-process-maybe (&optional start-msg end-msg)
  "Start Geiser REPL configured for Guix if needed.
START-MSG and END-MSG are strings displayed in the minibuffer in
the beginning and in the end of the starting process.  If nil,
display default messages."
  (guix-start-repl-maybe nil
                         (or start-msg "Starting Guix REPL ...")
                         (or end-msg "Guix REPL has been started."))
  (if guix-use-guile-server
      (guix-start-repl-maybe 'internal)
    (setq guix-internal-repl-buffer guix-repl-buffer)))

(defun guix-start-repl-maybe (&optional internal start-msg end-msg)
  "Start Guix REPL if needed.
If INTERNAL is non-nil, start an internal REPL.

START-MSG and END-MSG are strings displayed in the minibuffer in
the beginning and in the end of the process.  If nil, do not
display messages."
  (let* ((repl-var (guix-get-repl-buffer-variable internal))
         (repl (symbol-value repl-var)))
    (unless (and (buffer-live-p repl)
                 (get-buffer-process repl))
      (and start-msg (message start-msg))
      (setq guix-repl-operation-p nil)
      (let ((geiser-guile-binary (guix-get-guile-program internal))
            (geiser-guile-init-file (or internal guix-helper-file))
            (repl (get-buffer-create
                   (guix-get-repl-buffer-name internal))))
        (condition-case err
            (guix-start-repl repl
                             (and internal
                                  (geiser-repl--read-address
                                   "localhost" guix-default-port)))
          (text-read-only
           (error (concat "Couldn't start Guix REPL.  Perhaps the port %s is busy.\n"
                          "See buffer '%s' for details")
                  guix-default-port (buffer-name repl))))
        (set repl-var repl)
        (and end-msg (message end-msg))
        (unless internal
          (run-hooks 'guix-after-start-repl-hook))))))

(defun guix-start-repl (buffer &optional address)
  "Start Guix REPL in BUFFER.
If ADDRESS is non-nil, connect to a remote guile process using
this address (it should be defined by
`geiser-repl--read-address')."
  ;; A mix of the code from `geiser-repl--start-repl' and
  ;; `geiser-repl--to-repl-buffer'.
  (let ((impl 'guile)
        (geiser-guile-load-path (cons guix-load-path
                                      geiser-guile-load-path))
        (geiser-repl-startup-time guix-repl-startup-time))
    (with-current-buffer buffer
      (geiser-repl-mode)
      (geiser-impl--set-buffer-implementation impl)
      (geiser-repl--autodoc-mode -1)
      (goto-char (point-max))
      (let ((prompt (geiser-con--combined-prompt
                     geiser-guile--prompt-regexp
                     geiser-guile--debugger-prompt-regexp)))
        (geiser-repl--save-remote-data address)
        (geiser-repl--start-scheme impl address prompt)
        (geiser-repl--quit-setup)
        (geiser-repl--history-setup)
        (setq-local geiser-repl--repls (list buffer))
        (geiser-repl--set-this-buffer-repl buffer)
        (setq geiser-repl--connection
              (geiser-con--make-connection
               (get-buffer-process (current-buffer))
               geiser-guile--prompt-regexp
               geiser-guile--debugger-prompt-regexp))
        (geiser-repl--startup impl address)
        (geiser-repl--autodoc-mode 1)
        (geiser-company--setup geiser-repl-company-p)
        (add-hook 'comint-output-filter-functions
                  'guix-repl-output-filter
                  nil t)
        (set-process-query-on-exit-flag
         (get-buffer-process (current-buffer))
         geiser-repl-query-on-kill-p)))))

(defun guix-repl-output-filter (str)
  "Filter function suitable for `comint-output-filter-functions'.
This is a replacement for `geiser-repl--output-filter'."
  (cond
   ((string-match-p geiser-guile--prompt-regexp str)
    (geiser-autodoc--disinhibit-autodoc)
    (when guix-repl-operation-p
      (setq guix-repl-operation-p nil)
      (run-hooks 'guix-after-repl-operation-hook)
      ;; Run hooks specific to the current operation type.
      (when guix-repl-operation-type
        (let ((type-hook (intern
                          (concat "guix-after-"
                                  (symbol-name guix-repl-operation-type)
                                  "-hook"))))
          (setq guix-repl-operation-type nil)
          (and (boundp type-hook)
               (run-hooks type-hook))))))
   ((string-match geiser-guile--debugger-prompt-regexp str)
    (setq guix-repl-operation-p nil)
    (geiser-con--connection-set-debugging geiser-repl--connection
                                          (match-beginning 0))
    (geiser-autodoc--disinhibit-autodoc))))

(defun guix-repl-exit (&optional internal no-wait)
  "Exit the current Guix REPL.
If INTERNAL is non-nil, exit the internal REPL.
If NO-WAIT is non-nil, do not wait for the REPL process to exit:
send a kill signal to it and return immediately."
  (let ((repl (symbol-value (guix-get-repl-buffer-variable internal))))
    (when (get-buffer-process repl)
      (with-current-buffer repl
        (geiser-con--connection-deactivate geiser-repl--connection t)
        (comint-kill-subjob)
        (unless no-wait
          (while (get-buffer-process repl)
            (sleep-for 0.1)))))))

(defun guix-get-repl-buffer (&optional internal)
  "Return Guix REPL buffer; start REPL if needed.
If INTERNAL is non-nil, return an additional internal REPL."
  (guix-start-process-maybe)
  (let ((repl (symbol-value (guix-get-repl-buffer-variable internal))))
    ;; If a new Geiser REPL is started, `geiser-repl--repl' variable may
    ;; be set to the new value in a Guix REPL, so set it back to a
    ;; proper value here.
    (with-current-buffer repl
      (geiser-repl--set-this-buffer-repl repl))
    repl))

(defun guix-get-repl-buffer-variable (&optional internal)
  "Return the name of a variable with a REPL buffer."
  (if internal
      'guix-internal-repl-buffer
    'guix-repl-buffer))

(defun guix-get-repl-buffer-name (&optional internal)
  "Return the name of a REPL buffer."
  (if internal
      guix-internal-repl-buffer-name
    guix-repl-buffer-name))

(defun guix-switch-to-repl (&optional internal)
  "Switch to Guix REPL.
If INTERNAL is non-nil (interactively with prefix), switch to the
additional internal REPL if it exists."
  (interactive "P")
  (geiser-repl--switch-to-buffer (guix-get-repl-buffer internal)))


;;; Evaluating expressions

(defvar guix-operation-buffer nil
  "Buffer from which the latest Guix operation was performed.")

(defun guix-make-guile-expression (fun &rest args)
  "Return string containing a guile expression for calling FUN with ARGS."
  (format "(%S %s)" fun
          (mapconcat
           (lambda (arg)
             (cond
              ((null arg) "'()")
              ((or (eq arg t)
                   ;; An ugly hack to separate 'false' from nil
                   (equal arg 'f)
                   (keywordp arg))
               (concat "#" (prin1-to-string arg t)))
              ((or (symbolp arg) (listp arg))
               (concat "'" (prin1-to-string arg)))
              (t (prin1-to-string arg))))
           args
           " ")))

(defun guix-eval (str &optional wrap)
  "Evaluate guile expression STR.
If WRAP is non-nil, wrap STR into (begin ...) form.
Return a list of strings with result values of evaluation."
  (with-current-buffer (guix-get-repl-buffer 'internal)
    (let* ((wrapped (if wrap (geiser-debug--wrap-region str) str))
           (code `(:eval (:scm ,wrapped)))
           (ret (geiser-eval--send/wait code)))
      (if (geiser-eval--retort-error ret)
          (error "Error in evaluating guile expression: %s"
                 (geiser-eval--retort-output ret))
        (cdr (assq 'result ret))))))

(defun guix-eval-read (str &optional wrap)
  "Evaluate guile expression STR.
For the meaning of WRAP, see `guix-eval'.
Return elisp expression of the first result value of evaluation."
  ;; Parsing scheme code with elisp `read' is probably not the best idea.
  (read (replace-regexp-in-string
         "#f\\|#<unspecified>" "nil"
         (replace-regexp-in-string
          "#t" "t" (car (guix-eval str wrap))))))

(defun guix-eval-in-repl (str &optional operation-buffer operation-type)
  "Switch to Guix REPL and evaluate STR with guile expression there.
If OPERATION-BUFFER is non-nil, it should be a buffer from which
the current operation was performed.

If OPERATION-TYPE is non-nil, it should be a symbol.  After
successful executing of the current operation,
`guix-after-OPERATION-TYPE-hook' is called."
  (run-hooks 'guix-before-repl-operation-hook)
  (setq guix-repl-operation-p t
        guix-repl-operation-type operation-type
        guix-operation-buffer operation-buffer)
  (let ((repl (guix-get-repl-buffer)))
    (with-current-buffer repl
      (geiser-repl--send str))
    (geiser-repl--switch-to-buffer repl)))

(provide 'guix-backend)

;;; guix-backend.el ends here