05/20: emacs: Add and use 'guix-concat-strings'.

[Alex Kost]

alezost pushed a commit to branch wip-emacs-popup-ui
in repository guix.

commit 522c86b1538fde7eab042d86794fd4aadf5f1d6c
Author: Alex Kost <address@hidden>
Date:   Wed Aug 12 15:44:22 2015 +0300

    emacs: Add and use 'guix-concat-strings'.
    
    * emacs/guix-utils.el (guix-concat-strings): New function.
    * emacs/guix-pcomplete.el (guix-pcomplete-short-options): Use it.
    * emacs/guix-base.el (guix-get-package-strings): Likewise.
---
 emacs/guix-base.el      |    2 +-
 emacs/guix-pcomplete.el |    2 +-
 emacs/guix-utils.el     |   16 ++++++++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/emacs/guix-base.el b/emacs/guix-base.el
index 7ec68ec..2a59a5b 100644
--- a/emacs/guix-base.el
+++ b/emacs/guix-base.el
@@ -947,7 +947,7 @@ ENTRIES is a list of package entries to get info about 
packages."
                  (concat (guix-get-full-name entry)
                          (when outputs
                            (concat ":"
-                                   (mapconcat #'identity outputs ",")))
+                                   (guix-concat-strings outputs ",")))
                          (when location
                            (concat "\t(" location ")")))))))
          specs)))
diff --git a/emacs/guix-pcomplete.el b/emacs/guix-pcomplete.el
index 99bc29f..fe1b1ef 100644
--- a/emacs/guix-pcomplete.el
+++ b/emacs/guix-pcomplete.el
@@ -146,7 +146,7 @@ subcommands, actions, etc. for this guix COMMAND."
   "Return a string with available short options for guix COMMAND."
   guix-pcomplete-parse-short-option-regexp
   (lambda (list)
-    (mapconcat #'identity list "")))
+    (guix-concat-strings list "")))
 
 (guix-memoized-defun guix-pcomplete-all-packages ()
   "Return a list of all available Guix packages."
diff --git a/emacs/guix-utils.el b/emacs/guix-utils.el
index 8a0673a..df6636c 100644
--- a/emacs/guix-utils.el
+++ b/emacs/guix-utils.el
@@ -128,6 +128,22 @@ split it into several short lines."
       (fill-region (point-min) (point-max)))
     (buffer-string)))
 
+(defun guix-concat-strings (strings separator &optional location)
+  "Return new string by concatenating STRINGS with SEPARATOR.
+If LOCATION is a symbol `head', add another SEPARATOR to the
+beginning of the returned string; if `tail' - add SEPARATOR to
+the end of the string; if nil, do not add SEPARATOR; otherwise
+add both to the end and to the beginning."
+  (let ((str (mapconcat #'identity strings separator)))
+    (cond ((null location)
+           str)
+          ((eq location 'head)
+           (concat separator str))
+          ((eq location 'tail)
+           (concat str separator))
+          (t
+           (concat separator str separator)))))
+
 (defun guix-completing-read-multiple (prompt table &optional predicate
                                       require-match initial-input
                                       hist def inherit-input-method)