[PATCH 4/7] emacs: Add 'guix-devel-use-current-module'.

[Alex Kost <alezost@gmail.com>]

* emacs/guix-guile.el (guix-guile-current-module): New function.
* emacs/guix-devel.el: New file.
  (guix-devel-use-modules, guix-devel-use-current-module): New functions.
* doc/emacs.texi (Emacs Development): New node.  Document
  'guix-devel-use-current-module'.
---
 doc/emacs.texi      | 29 ++++++++++++++++++++++++++++-
 emacs/guix-devel.el | 44 ++++++++++++++++++++++++++++++++++++++++++++
 emacs/guix-guile.el | 13 +++++++++++++
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 emacs/guix-devel.el

diff --git a/doc/emacs.texi b/doc/emacs.texi
index 180037a..6920bef 100644
--- a/doc/emacs.texi
+++ b/doc/emacs.texi
@@ -19,7 +19,8 @@ guix package}).  Specifically, ``guix.el'' makes it easy to:
 * Usage: Emacs Usage.			Using the interface.
 * Configuration: Emacs Configuration.	Configuring the interface.
 * Prettify Mode: Emacs Prettify.	Abbreviating @file{/gnu/store/@dots{}} file names.
-* Completions: Emacs Completions.       Completing @command{guix} shell command.
+* Completions: Emacs Completions.	Completing @command{guix} shell command.
+* Development: Emacs Development.	Tools for Guix developers.
 @end menu
 
 @node Emacs Initial Setup
@@ -554,3 +555,29 @@ something:
 @item @code{guix lint --checkers=synopsis,des}@key{TAB}
 
 @end itemize
+
+
+@node Emacs Development
+@subsection Development
+
+This section describes some additional commands for Guix developers who
+use Geiser to work with guile code.
+
+@table @kbd
+
+@item M-x guix-devel-use-current-module
+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.
+
+@end table
+
+And as always if you use a command often, it is a good idea to bind a
+key to it, for example like this:
+
+@example
+(with-eval-after-load 'scheme
+  (define-key scheme-mode-map (kbd "C-c u")
+    'guix-devel-use-current-module))
+@end example
diff --git a/emacs/guix-devel.el b/emacs/guix-devel.el
new file mode 100644
index 0000000..e99b289
--- /dev/null
+++ b/emacs/guix-devel.el
@@ -0,0 +1,44 @@
+;;; guix-devel.el --- Development tools
+
+;; Copyright © 2015 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 commands useful for developing Guix (or even arbitrary
+;; guile code) with Geiser.
+
+;;; Code:
+
+(require 'guix-guile)
+(require 'guix-geiser)
+
+(defun guix-devel-use-modules (&rest modules)
+  "Use guile MODULES."
+  (apply #'guix-geiser-call "use-modules" modules))
+
+;;;###autoload
+(defun guix-devel-use-current-module ()
+  "Use the current guile module."
+  (interactive)
+  (let ((module (guix-guile-current-module)))
+    (guix-devel-use-modules module)
+    (message "Using %s module." module)))
+
+(provide 'guix-devel)
+
+;;; guix-devel.el ends here
diff --git a/emacs/guix-guile.el b/emacs/guix-guile.el
index 87af192..ffa8848 100644
--- a/emacs/guix-guile.el
+++ b/emacs/guix-guile.el
@@ -24,6 +24,19 @@
 
 ;;; Code:
 
+(require 'geiser-guile)
+
+(defun guix-guile-current-module ()
+  "Return string with current guile module.
+Return nil, if current buffer does not define a module."
+  ;; Modified version of `geiser-guile--get-module'.
+  (save-excursion
+    (geiser-syntax--pop-to-top)
+    (when (or (re-search-backward geiser-guile--module-re nil t)
+              (looking-at geiser-guile--library-re)
+              (re-search-forward geiser-guile--module-re nil t))
+      (match-string-no-properties 1))))
+
 (defun guix-guile-make-call-expression (proc &rest args)
   "Return \"(PROC ARGS ...)\" string.
 PROC and ARGS should be strings."
-- 
2.4.3