162/197: gurses: Avoid one use of car/cdr.

[Danny Milosavljevic]

dannym pushed a commit to branch wip-installer-2
in repository guix.

commit c969da3496d54eb56df0402355bc53d4ba31966f
Author: John Darrington <address@hidden>
Date:   Wed Feb 1 16:12:25 2017 +0100

    gurses: Avoid one use of car/cdr.
    
    * gurses/buttons.scm (buttons-post): Use match instead of car/cdr
---
 gurses/buttons.scm | 73 +++++++++++++++++++++++++++---------------------------
 1 file changed, 36 insertions(+), 37 deletions(-)

diff --git a/gurses/buttons.scm b/gurses/buttons.scm
index eaa7e31..5afef38 100644
--- a/gurses/buttons.scm
+++ b/gurses/buttons.scm
@@ -31,6 +31,7 @@
   #:export (buttons-key-matches-symbol?)
 
   #:use-module (ncurses curses)
+  #:use-module (ice-9 match)
   #:use-module (srfi srfi-9))
 
 (define-record-type <buttons>
@@ -114,43 +115,41 @@
     (let loop ((bl (buttons-items buttons))
               (i 0)
               (alist '()))
-      (if (null? bl)
-         (reverse alist)
-         (let* ((but (car bl))
-                (key (car but))
-                (raw-label (gettext (cadr but)))
-                (use-underscore (caddr but))
-                ;; Convert the raw-label into a "complex rendered string" which
-                ;; has the mnemonic character highlighted
-                (label.mark
-                 (let mk-label ((us #f)
-                                (mark #f)
-                                (output '())
-                                (input (string->list raw-label)))
-                   (if (null? input)
-                       (cons (reverse output) mark)
-                       (let ((c (car input)))
-                         (mk-label (eq? c #\_)
-                                   (if mark mark (if us c #f))
-                                   (if (and (eq? c #\_) use-underscore)
-                                       output
-                                       (cons
-                                        (if us
-                                             ;; On some terminals bold isn't 
visible
-                                             ;; Inverse is much clearer.
-                                             (inverse c)
-                                             (normal c))
-                                        output))
-                                   (cdr input))))))
-                (label (car label.mark))
-                (mark  (cdr label.mark))
-                (width (+ (length label) 2))
-                (w (derwin win 3 width 0
-                           (round (- (* (1+ i) (/ (getmaxx win) (1+ n)))
-                                     (/ width 2))) #:panel #f)))
-           (box w   0 0)
-           (addchstr w label #:y 1 #:x 1)
-           (loop (cdr bl) (1+ i) (acons mark (list w key) alist))))))))
+      (match bl
+             (()         (reverse alist))
+             (((key raw-label use-underscore) . _)
+              (let* (
+                     ;; Convert the raw-label into a "complex rendered string" 
which
+                     ;; has the mnemonic character highlighted
+                     (label.mark
+                      (let mk-label ((us #f)
+                                     (mark #f)
+                                     (output '())
+                                     (input (string->list raw-label)))
+                        (if (null? input)
+                            (cons (reverse output) mark)
+                            (let ((c (car input)))
+                              (mk-label (eq? c #\_)
+                                        (if mark mark (if us c #f))
+                                        (if (and (eq? c #\_) use-underscore)
+                                            output
+                                            (cons
+                                             (if us
+                                                 ;; On some terminals bold 
isn't visible
+                                                 ;; Inverse is much clearer.
+                                                 (inverse c)
+                                                 (normal c))
+                                             output))
+                                        (cdr input))))))
+                     (label (car label.mark))
+                     (mark  (cdr label.mark))
+                     (width (+ (length label) 2))
+                     (w (derwin win 3 width 0
+                                (round (- (* (1+ i) (/ (getmaxx win) (1+ n)))
+                                          (/ width 2))) #:panel #f)))
+                (box w   0 0)
+                (addchstr w label #:y 1 #:x 1)
+                (loop (cdr bl) (1+ i) (acons mark (list w key) alist)))))))))