aboutsummaryrefslogtreecommitdiff
path: root/doc/emacs.texi
blob: d46c17c4a0af1ce3c1747834da66bc0bb2d13203 (about) (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
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
@node Emacs Interface
@chapter Emacs Interface

@cindex Emacs
GNU Guix comes with several useful modules (known as ``guix.el'') for
GNU@tie{}Emacs which are intended to make an Emacs user interaction with
Guix convenient and fun.

@menu
* Initial Setup: Emacs Initial Setup.	Preparing @file{~/.emacs}.
* Package Management: Emacs Package Management.	Managing packages and generations.
* Licenses: Emacs Licenses.		Interface for licenses of Guix packages.
* Popup Interface: Emacs Popup Interface.	Magit-like interface for guix commands.
* Prettify Mode: Emacs Prettify.	Abbreviating @file{/gnu/store/@dots{}} file names.
* Build Log Mode: Emacs Build Log.	Highlighting Guix build logs.
* Completions: Emacs Completions.	Completing @command{guix} shell command.
* Development: Emacs Development.	Tools for Guix developers.
* Hydra: Emacs Hydra.			Interface for Guix build farm.
@end menu


@node Emacs Initial Setup
@section Initial Setup

On the Guix System Distribution (@pxref{GNU Distribution}), ``guix.el''
is ready to use, provided Guix is installed system-wide, which is the
case by default.  So if that is what you're using, you can happily skip
this section and read about the fun stuff.

If you're not yet a happy user of GuixSD, a little bit of setup is needed.
To be able to use ``guix.el'', you need to install the following
packages:

@itemize
@item
@uref{http://www.gnu.org/software/emacs/, GNU Emacs}, version 24.3 or
later;

@item
@uref{http://nongnu.org/geiser/, Geiser}, version 0.3 or later: it is
used for interacting with the Guile process.

@item
@uref{https://github.com/magit/magit/, magit-popup library}.  You
already have this library if you use Magit 2.1.0 or later.  This library
is an optional dependency---it is required only for @kbd{M-x@tie{}guix}
command (@pxref{Emacs Popup Interface}).

@end itemize

When it is done ``guix.el'' may be configured by requiring a special
@code{guix-init} file---i.e., by adding the following code into your
init file (@pxref{Init File,,, emacs, The GNU Emacs Manual}):

@example
(add-to-list 'load-path "/path/to/directory-with-guix.el")
(require 'guix-init nil t)
@end example

So the only thing you need to figure out is where the directory with
elisp files for Guix is placed.  It depends on how you installed Guix:

@itemize
@item
If it was installed by a package manager of your distribution or by a
usual @code{./configure && make && make install} command sequence, then
elisp files are placed in a standard directory with Emacs packages
(usually it is @file{/usr/share/emacs/site-lisp/}), which is already in
@code{load-path}, so there is no need to add that directory there.

@item
If you used a binary installation method (@pxref{Binary Installation}),
then Guix is installed somewhere in the store, so the elisp files are
placed in @file{/gnu/store/@dots{}-guix-0.8.2/share/emacs/site-lisp/} or
alike.  However it is not recommended to refer directly to a store
directory.  Instead you can install Guix using Guix itself with
@command{guix package -i guix} command (@pxref{Invoking guix package})
and add @file{~/.guix-profile/share/emacs/site-lisp/} directory to
@code{load-path} variable.

@item
If you did not install Guix at all and prefer a hacking way
(@pxref{Running Guix Before It Is Installed}), along with augmenting
@code{load-path} you need to set @code{guix-load-path} variable to the
same directory, so your final configuration will look like this:

@example
(let ((dir "/path/to/your-guix-git-tree/emacs"))
  (add-to-list 'load-path dir)
  (setq guix-load-path dir))
(require 'guix-init nil t)
@end example
@end itemize

By default, along with autoloading (@pxref{Autoload,,, elisp, The GNU
Emacs Lisp Reference Manual}) the main interactive commands for
``guix.el'' (@pxref{Emacs Commands}), requiring @code{guix-init} will
also autoload commands for the Emacs packages installed in your user
profile.

To disable automatic loading of installed Emacs packages, set
@code{guix-package-enable-at-startup} variable to @code{nil} before
requiring @code{guix-init}.  This variable has the same meaning for
Emacs packages installed with Guix, as @code{package-enable-at-startup}
for the built-in Emacs package system (@pxref{Package Installation,,,
emacs, The GNU Emacs Manual}).

You can activate Emacs packages installed in your profile whenever you
want using @kbd{M-x@tie{}guix-emacs-autoload-packages}.


@node Emacs Package Management
@section Package Management

Once ``guix.el'' has been successfully configured, you should be able to
use a visual interface for routine package management tasks, pretty much
like the @command{guix package} command (@pxref{Invoking guix package}).
Specifically, it makes it easy to:

@itemize
@item browse and display packages and generations;
@item search, install, upgrade and remove packages;
@item display packages from previous generations;
@item do some other useful things.
@end itemize

@menu
* Commands: Emacs Commands.			@kbd{M-x guix-@dots{}}
* General information: Emacs General info.	Common for both interfaces.
* ``List'' buffer: Emacs List buffer.		List-like interface.
* ``Info'' buffer: Emacs Info buffer.		Help-like interface.
* Configuration: Emacs Configuration.		Configuring the interface.
@end menu

@node Emacs Commands
@subsection Commands

All commands for displaying packages and generations use the current
profile, which can be changed with
@kbd{M-x@tie{}guix-set-current-profile}.  Alternatively, if you call any
of these commands with prefix argument (@kbd{C-u}), you will be prompted
for a profile just for that command.

Commands for displaying packages:

@table @kbd

@item M-x guix-all-available-packages
@itemx M-x guix-newest-available-packages
Display all/newest available packages.

@item M-x guix-installed-packages
Display all installed packages.

@item M-x guix-obsolete-packages
Display obsolete packages (the packages that are installed in a profile
but cannot be found among available packages).

@item M-x guix-packages-by-name
Display package(s) with the specified name.

@item M-x guix-packages-by-license
Display package(s) with the specified license.

@item M-x guix-search-by-regexp
Search for packages by a specified regexp.  By default ``name'',
``synopsis'' and ``description'' of the packages will be searched.  This
can be changed by modifying @code{guix-package-search-params} variable.

@item M-x guix-search-by-name
Search for packages with names matching a specified regexp.  This
command is the same as @code{guix-search-by-regexp}, except only a
package ``name'' is searched.

@end table

By default, these commands display each output on a separate line.  If
you prefer to see a list of packages---i.e., a list with a package per
line, use the following setting:

@example
(setq guix-package-list-type 'package)
@end example

Commands for displaying generations:

@table @kbd

@item M-x guix-generations
List all the generations.

@item M-x guix-last-generations
List the @var{N} last generations.  You will be prompted for the number
of generations.

@item M-x guix-generations-by-time
List generations matching time period.  You will be prompted for the
period using Org mode time prompt based on Emacs calendar (@pxref{The
date/time prompt,,, org, The Org Manual}).

@end table

Analogously on GuixSD you can also display system generations:

@table @kbd
@item M-x guix-system-generations
@item M-x guix-last-system-generations
@item M-x guix-system-generations-by-time
@end table

You can also invoke the @command{guix pull} command (@pxref{Invoking
guix pull}) from Emacs using:

@table @kbd
@item M-x guix-pull
With @kbd{C-u}, make it verbose.
@end table

Once @command{guix pull} has succeeded, the Guix REPL is restared.  This
allows you to keep using the Emacs interface with the updated Guix.

Finally, there is an Emacs variant of @command{guix edit} command
(@pxref{Invoking guix edit}):

@table @kbd
@item M-x guix-edit
As with @kbd{M-x guix-packages-by-name}, you can press @key{TAB} to
complete a package name.
@end table

If you are contributing to Guix, you may find it useful for @kbd{M-x
guix-edit} to open package files from your git directory.  This can be
done by setting @code{guix-directory} variable.  For example, after
this:

@example
(setq guix-directory "~/src/guix")
@end example

@kbd{M-x guix-edit guix} opens
@file{~/src/guix/gnu/packages/package-management.scm} file.


@node Emacs General info
@subsection General information

The following keys are available for both ``list'' and ``info'' types of
buffers:

@table @kbd
@item l
@itemx r
Go backward/forward by the history of the displayed results (this
history is similar to the history of the Emacs @code{help-mode} or
@code{Info-mode}).

@item g
Revert current buffer: update information about the displayed
packages/generations and redisplay it.

@item R
Redisplay current buffer (without updating information).

@item M
Apply manifest to the current profile or to a specified profile, if
prefix argument is used.  This has the same meaning as @code{--manifest}
option (@pxref{Invoking guix package}).

@item C-c C-z
@cindex REPL
@cindex read-eval-print loop
Go to the Guix REPL (@pxref{The REPL,,, geiser, Geiser User Manual}).

@item h
@itemx ?
Describe current mode to see all available bindings.

@end table

@emph{Hint:} If you need several ``list'' or ``info'' buffers, you can
simlpy @kbd{M-x clone-buffer} them, and each buffer will have its own
history.

@emph{Warning:} Name/version pairs cannot be used to identify packages
(because a name is not necessarily unique), so ``guix.el'' uses special
identifiers that live only during a guile session, so if the Guix REPL
was restarted, you may want to revert ``list'' buffer (by pressing
@kbd{g}).

@node Emacs List buffer
@subsection ``List'' buffer

An interface of a ``list'' buffer is similar to the interface provided
by ``package.el'' (@pxref{Package Menu,,, emacs, The GNU Emacs Manual}).

Default key bindings available for both ``package-list'' and
``generation-list'' buffers:

@table @kbd
@item m
Mark the current entry (with prefix, mark all entries).
@item u
Unmark the current entry (with prefix, unmark all entries).
@item @key{DEL}
Unmark backward.
@item S
Sort entries by a specified column.
@end table

A ``package-list'' buffer additionally provides the following bindings:

@table @kbd
@item @key{RET}
Describe marked packages (display available information in a
``package-info'' buffer).
@item i
Mark the current package for installation.
@item d
Mark the current package for deletion.
@item U
Mark the current package for upgrading.
@item ^
Mark all obsolete packages for upgrading.
@item e
Edit the definition of the curent package (go to its location).  This is
similar to @command{guix edit} command (@pxref{Invoking guix edit}), but
for opening a package recipe in the current Emacs instance.
@item x
Execute actions on the marked packages.
@item B
Display latest builds of the current package (@pxref{Emacs Hydra}).
@end table

A ``generation-list'' buffer additionally provides the following
bindings:

@table @kbd
@item @key{RET}
List packages installed in the current generation.
@item i
Describe marked generations (display available information in a
``generation-info'' buffer).
@item s
Switch profile to the current generation.
@item d
Mark the current generation for deletion (with prefix, mark all
generations).
@item x
Execute actions on the marked generations---i.e., delete generations.
@item e
Run Ediff (@pxref{Top,,, ediff, The Ediff Manual}) on package outputs
installed in the 2 marked generations.  With prefix argument, run Ediff
on manifests of the marked generations.
@item D
@itemx =
Run Diff (@pxref{Diff Mode,,, emacs, The GNU Emacs Manual}) on package
outputs installed in the 2 marked generations.  With prefix argument,
run Diff on manifests of the marked generations.
@item +
List package outputs added to the latest marked generation comparing
with another marked generation.
@item -
List package outputs removed from the latest marked generation comparing
with another marked generation.
@end table

@node Emacs Info buffer
@subsection ``Info'' buffer

The interface of an ``info'' buffer is similar to the interface of
@code{help-mode} (@pxref{Help Mode,,, emacs, The GNU Emacs Manual}).

``Info'' buffer contains some buttons (as usual you may use @key{TAB} /
@kbd{S-@key{TAB}} to move between buttons---@pxref{Mouse References,,,
emacs, The GNU Emacs Manual}) which can be used to:

@itemize @bullet
@item (in a ``package-info'' buffer)

@itemize @minus
@item install/remove a package;
@item jump to a package location;
@item browse home page of a package;
@item browse license URL;
@item describe packages from ``Inputs'' fields.
@end itemize

@item (in a ``generation-info'' buffer)

@itemize @minus
@item remove a generation;
@item switch to a generation;
@item list packages installed in a generation;
@item jump to a generation directory.
@end itemize

@end itemize

It is also possible to copy a button label (a link to an URL or a file)
by pressing @kbd{c} on a button.


@node Emacs Configuration
@subsection Configuration

There are many variables you can modify to change the appearance or
behavior of Emacs user interface.  Some of these variables are described
in this section.  Also you can use Custom Interface (@pxref{Easy
Customization,,, emacs, The GNU Emacs Manual}) to explore/set variables
(not all) and faces.

@menu
* Guile and Build Options: Emacs Build Options.	Specifying how packages are built.
* Buffer Names: Emacs Buffer Names.	Names of Guix buffers.
* Keymaps: Emacs Keymaps.		Configuring key bindings.
* Appearance: Emacs Appearance.		Settings for visual appearance.
@end menu

@node Emacs Build Options
@subsubsection Guile and Build Options

@table @code
@item guix-guile-program
If you have some special needs for starting a Guile process, you may set
this variable, for example:

@example
(setq guix-guile-program '("/bin/guile" "--no-auto-compile"))
@end example

@item guix-use-substitutes
Has the same meaning as @code{--no-substitutes} option (@pxref{Invoking
guix build}).

@item guix-dry-run
Has the same meaning as @code{--dry-run} option (@pxref{Invoking guix
build}).

@end table

@node Emacs Buffer Names
@subsubsection Buffer Names

Default names of ``guix.el'' buffers (``*Guix@tie{}@dots{}*'') may be
changed with the following variables:

@table @code
@item guix-package-list-buffer-name
@item guix-output-list-buffer-name
@item guix-generation-list-buffer-name
@item guix-package-info-buffer-name
@item guix-output-info-buffer-name
@item guix-generation-info-buffer-name
@item guix-repl-buffer-name
@item guix-internal-repl-buffer-name
@end table

By default, the name of a profile is also displayed in a ``list'' or
``info'' buffer name.  To change this behavior, use
@code{guix-ui-buffer-name-function} variable.

For example, if you want to display all types of results in a single
buffer (in such case you will probably use a history (@kbd{l}/@kbd{r})
extensively), you may do it like this:

@example
(let ((name "Guix Universal"))
  (setq
   guix-package-list-buffer-name    name
   guix-output-list-buffer-name     name
   guix-generation-list-buffer-name name
   guix-package-info-buffer-name    name
   guix-output-info-buffer-name     name
   guix-generation-info-buffer-name name))
@end example

@node Emacs Keymaps
@subsubsection Keymaps

If you want to change default key bindings, use the following keymaps
(@pxref{Init Rebinding,,, emacs, The GNU Emacs Manual}):

@table @code
@item guix-buffer-map
Parent keymap with general keys for any buffer type.

@item guix-ui-map
Parent keymap with general keys for buffers used for Guix package
management (for packages, outputs and generations).

@item guix-list-mode-map
Parent keymap with general keys for ``list'' buffers.

@item guix-package-list-mode-map
Keymap with specific keys for ``package-list'' buffers.

@item guix-output-list-mode-map
Keymap with specific keys for ``output-list'' buffers.

@item guix-generation-list-mode-map
Keymap with specific keys for ``generation-list'' buffers.

@item guix-info-mode-map
Parent keymap with general keys for ``info'' buffers.

@item guix-package-info-mode-map
Keymap with specific keys for ``package-info'' buffers.

@item guix-output-info-mode-map
Keymap with specific keys for ``output-info'' buffers.

@item guix-generation-info-mode-map
Keymap with specific keys for ``generation-info'' buffers.

@item guix-info-button-map
Keymap with keys available when a point is placed on a button.

@end table

@node Emacs Appearance
@subsubsection Appearance

You can change almost any aspect of ``list'' / ``info'' buffers using
the following variables (@dfn{ENTRY-TYPE} means @code{package},
@code{output} or @code{generation}):

@table @code
@item guix-ENTRY-TYPE-list-format
@itemx guix-ENTRY-TYPE-list-titles
Specify the columns, their names, what and how is displayed in ``list''
buffers.

@item guix-ENTRY-TYPE-info-format
@itemx guix-ENTRY-TYPE-info-titles
@itemx guix-info-ignore-empty-values
@itemx guix-info-param-title-format
@itemx guix-info-multiline-prefix
@itemx guix-info-indent
@itemx guix-info-fill
@itemx guix-info-delimiter
Various settings for ``info'' buffers.

@end table


@node Emacs Licenses
@section Licenses

If you want to browse the URL of a particular license, or to look at a
list of licenses, you may use the following commands:

@table @kbd

@item M-x guix-browse-license-url
Choose a license from a completion list to browse its URL using
@code{browse-url} function (@pxref{Browse-URL,,, emacs, The GNU Emacs
Manual}).

@item M-x guix-licenses
Display a list of available licenses.  You can press @kbd{@key{RET}}
there to display packages with this license in the same way as @kbd{M-x
guix-packages-by-license} would do (@pxref{Emacs Commands}).

@end table


@node Emacs Popup Interface
@section Popup Interface

If you ever used Magit, you know what ``popup interface'' is
(@pxref{Top,,, magit-popup, Magit-Popup User Manual}).  Even if you are
not acquainted with Magit, there should be no worries as it is very
intuitive.

So @kbd{M-x@tie{}guix} command provides a top-level popup interface for
all available guix commands.  When you select an option, you'll be
prompted for a value in the minibuffer.  Many values have completions,
so don't hesitate to press @key{TAB} key.  Multiple values (for example,
packages or lint checkers) should be separated by commas.

After specifying all options and switches for a command, you may choose
one of the available actions.  The following default actions are
available for all commands:

@itemize

@item
Run the command in the Guix REPL.  It is faster than running
@code{guix@tie{}@dots{}} command directly in shell, as there is no
need to run another guile process and to load required modules there.

@item
Run the command in a shell buffer.  You can set
@code{guix-run-in-shell-function} variable to fine tune the shell buffer
you want to use.

@item
Add the command line to the kill ring (@pxref{Kill Ring,,, emacs, The
GNU Emacs Manual}).

@end itemize

Several commands (@command{guix graph}, @command{guix system shepherd-graph}
and @command{guix system extension-graph}) also have a ``View graph''
action, which allows you to view a generated graph using @command{dot}
command (specified by @code{guix-dot-program} variable).  By default a
PNG file will be saved in @file{/tmp} directory and will be opened
directly in Emacs.  This behavior may be changed with the following
variables:

@table @code

@item guix-find-file-function
Function used to open a generated graph.  If you want to open a graph in
an external program, you can do it by modifying this variable---for
example, you can use a functionality provided by the Org Mode
(@pxref{Top,,, org, The Org Manual}):

@example
(setq guix-find-file-function 'org-open-file)
(add-to-list 'org-file-apps '("\\.png\\'" . "sxiv %s"))
@end example

@item guix-dot-default-arguments
Command line arguments to run @command{dot} command.  If you change an
output format (for example, into @code{-Tpdf}), you also need to change
the next variable.

@item guix-dot-file-name-function
Function used to define a name of the generated graph file.  Default
name is @file{/tmp/guix-emacs-graph-XXXXXX.png}.

@end table

So, for example, if you want to generate and open a PDF file in your
Emacs, you may change the settings like this:

@example
(defun my-guix-pdf-graph ()
  "/tmp/my-current-guix-graph.pdf")

(setq guix-dot-default-arguments '("-Tpdf")
      guix-dot-file-name-function 'my-guix-pdf-graph)
@end example


@node Emacs Prettify
@section Guix Prettify Mode

GNU@tie{}Guix also comes with ``guix-prettify.el''.  It provides a minor
mode for abbreviating store file names by replacing hash sequences of
symbols with ``@dots{}'':

@example
/gnu/store/72f54nfp6g1hz873w8z3gfcah0h4nl9p-foo-0.1
@result{} /gnu/store/…-foo-0.1
@end example

Once you set up ``guix.el'' (@pxref{Emacs Initial Setup}), the following
commands become available:

@table @kbd

@item M-x guix-prettify-mode
Enable/disable prettifying for the current buffer.

@item M-x global-guix-prettify-mode
Enable/disable prettifying globally.

@end table

To automatically enable @code{guix-prettify-mode} globally on Emacs
start, add the following line to your init file:

@example
(global-guix-prettify-mode)
@end example

If you want to enable it only for specific major modes, add it to the
mode hooks (@pxref{Hooks,,, emacs, The GNU Emacs Manual}), for example:

@example
(add-hook 'shell-mode-hook 'guix-prettify-mode)
(add-hook 'dired-mode-hook 'guix-prettify-mode)
@end example


@node Emacs Build Log
@section Build Log Mode

GNU@tie{}Guix provides major and minor modes for highlighting build
logs.  So when you have a file with a package build output---for
example, a file returned by @command{guix build --log-file @dots{}}
command (@pxref{Invoking guix build}), you may call @kbd{M-x
guix-build-log-mode} command in the buffer with this file.  This major
mode highlights some lines specific to build output and provides the
following key bindings:

@table @kbd

@item M-n
Move to the next build phase.

@item M-p
Move to the previous build phase.

@item @key{TAB}
Toggle (show/hide) the body of the current build phase.

@item S-@key{TAB}
Toggle (show/hide) the bodies of all build phases.

@end table

There is also @kbd{M-x guix-build-log-minor-mode} which also provides
the same highlighting and the same key bindings as the major mode, but
prefixed with @kbd{C-c}.  By default, this minor mode is enabled in
shell buffers (@pxref{Interactive Shell,,, emacs, The GNU Emacs
Manual}).  If you don't like it, set
@code{guix-build-log-minor-mode-activate} to nil.


@node Emacs Completions
@section Shell Completions

Another feature that becomes available after configuring Emacs interface
(@pxref{Emacs Initial Setup}) is completing of @command{guix}
subcommands, options, packages and other things in @code{shell}
(@pxref{Interactive Shell,,, emacs, The GNU Emacs Manual}) and
@code{eshell} (@pxref{Top,,, eshell, Eshell: The Emacs Shell}).

It works the same way as other completions do.  Just press @key{TAB}
when your intuition tells you.

And here are some examples, where pressing @key{TAB} may complete
something:

@itemize @w{}

@item @code{guix pa}@key{TAB}
@item @code{guix package -}@key{TAB}
@item @code{guix package --}@key{TAB}
@item @code{guix package -i gei}@key{TAB}
@item @code{guix build -L/tm}@key{TAB}
@item @code{guix build --sy}@key{TAB}
@item @code{guix build --system=i}@key{TAB}
@item @code{guix system rec}@key{TAB}
@item @code{guix lint --checkers=sy}@key{TAB}
@item @code{guix lint --checkers=synopsis,des}@key{TAB}

@end itemize


@node Emacs Development
@section Development

By default, when you open a Scheme file, @code{guix-devel-mode} will be
activated (if you don't want it, set @code{guix-devel-activate-mode} to
nil).  This minor mode provides the following key bindings:

@table @kbd

@item C-c . k
Copy the name of the current Guile module into kill ring
(@code{guix-devel-copy-module-as-kill}).

@item C-c . u
Use the current Guile module.  Often after opening a Scheme file, you
want to use a module it defines, so you switch to the Geiser REPL and
write @code{,use (some module)} there.  You may just use this command
instead (@code{guix-devel-use-module}).

@item C-c . b
Build a package defined by the current variable definition.  The
building process is run in the current Geiser REPL.  If you modified the
current package definition, don't forget to reevaluate it before calling
this command---for example, with @kbd{C-M-x} (@pxref{To eval or not to
eval,,, geiser, Geiser User Manual})
(@code{guix-devel-build-package-definition}).

@item C-c . s
Build a source derivation of the package defined by the current variable
definition.  This command has the same meaning as @code{guix build -S}
shell command (@pxref{Invoking guix build})
(@code{guix-devel-build-package-source}).

@item C-c . l
Lint (check) a package defined by the current variable definition
(@pxref{Invoking guix lint}) (@code{guix-devel-lint-package}).

@end table

Unluckily, there is a limitation related to long-running REPL commands.
When there is a running process in a Geiser REPL, you are not supposed
to evaluate anything in a scheme buffer, because this will ``freeze''
the REPL: it will stop producing any output (however, the evaluating
process will continue---you will just not see any progress anymore).  Be
aware: even moving the point in a scheme buffer may ``break'' the REPL
if Autodoc (@pxref{Autodoc and friends,,, geiser, Geiser User Manual})
is enabled (which is the default).

So you have to postpone editing your scheme buffers until the running
evaluation will be finished in the REPL.

Alternatively, to avoid this limitation, you may just run another Geiser
REPL, and while something is being evaluated in the previous REPL, you
can continue editing a scheme file with the help of the current one.


@node Emacs Hydra
@section Hydra

The continuous integration server at @code{hydra.gnu.org} builds all
the distribution packages on the supported architectures and serves
them as substitutes (@pxref{Substitutes}).  Continuous integration is
currently orchestrated by @uref{https://nixos.org/hydra/, Hydra}.

This section describes an Emacs interface to query Hydra to know the
build status of specific packages, discover recent and ongoing builds,
view build logs, and so on.  This interface is mostly the same as the
``list''/``info'' interface for displaying packages and generations
(@pxref{Emacs Package Management}).

The following commands are available:

@table @kbd

@item M-x guix-hydra-latest-builds
Display latest failed or successful builds (you will be prompted for a
number of builds).  With @kbd{C-u}, you will also be prompted for other
parameters (project, jobset, job and system).

@item M-x guix-hydra-queued-builds
Display scheduled or currently running builds (you will be prompted for
a number of builds).

@item M-x guix-hydra-jobsets
Display available jobsets (you will be prompted for a project).

@end table

In a list of builds you can press @kbd{L} key to display a build log of
the current build.  Also both a list of builds and a list of jobsets
provide @kbd{B} key to display latest builds of the current job or
jobset (don't forget about @kbd{C-u}).