22/29: website: packages: /packages shows at most 30 packages.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix-artwork.

commit 94e9756e61cd564ae365f9525f95da906c38db13
Author: Ludovic Courtès <address@hidden>
Date:   Wed Dec 6 14:03:52 2017 +0100

    website: packages: /packages shows at most 30 packages.
    
    * website/apps/packages/templates/detailed-index.scm (detailed-index-t):
    Add optional 'total' parameter and honor it.
    * website/apps/packages/builder.scm (%max-packages-on-index): New variable.
    (index-builder): Use 'take-at-most' to limit the number of packages shown.
    (detailed-index-builder): Likewise, and pass the total to 
'detailed-index-t'.
    * website/apps/packages/utils.scm (take-at-most): New procedure.
---
 website/apps/packages/builder.scm                  | 39 ++++++++++++++++++----
 website/apps/packages/templates/detailed-index.scm |  7 ++--
 website/apps/packages/utils.scm                    | 17 +++++++++-
 3 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/website/apps/packages/builder.scm 
b/website/apps/packages/builder.scm
index 2382c5b..ba0592e 100644
--- a/website/apps/packages/builder.scm
+++ b/website/apps/packages/builder.scm
@@ -1,6 +1,23 @@
 ;;; GuixSD website --- GNU's advanced distro website
-;;; Initially written by sirgazil who waives all
-;;; copyright interest on this file.
+;;; Copyright © 2017 Ludovic Courtès <address@hidden>
+;;;
+;;; Initially written by sirgazil
+;;; who waives all copyright interest on this file.
+;;;
+;;; This file is part of GuixSD website.
+;;;
+;;; GuixSD website is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU Affero General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GuixSD website 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 Affero General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Affero General Public License
+;;; along with GuixSD website.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (apps packages builder)
   #:use-module (apps aux lists)
@@ -66,18 +83,28 @@
 ;;; Helper builders.
 ;;;
 
+(define %max-packages-on-index
+  ;; Maximum number of packages shown on /packages.
+  30)
+
 (define (index-builder)
   "Return a Haunt page listing some random packages."
-  ;; TODO: Pass ~30 random Guix packages.
-  (let ((context (list (cons "packages" (all-packages)))))
+  ;; TODO: Pick random packages.
+  (let ((context (list (cons "packages"
+                             (take-at-most (all-packages)
+                                           %max-packages-on-index)))))
     (make-page "packages/index.html" (index-t context) sxml->html)))
 
 
 (define (detailed-index-builder)
   "Return a Haunt page listing some random packages."
   ;; TODO: Pass ~30 random Guix packages.
-  (let ((context (list (cons "packages" (all-packages)))))
-    (make-page "packages/index.html" (detailed-index-t context) sxml->html)))
+  (let ((context (list (cons "packages"
+                             (take-at-most (all-packages)
+                                           %max-packages-on-index)))))
+    (make-page "packages/index.html"
+               (detailed-index-t context (length (all-packages)))
+               sxml->html)))
 
 
 (define (detailed-package-list-builder)
diff --git a/website/apps/packages/templates/detailed-index.scm 
b/website/apps/packages/templates/detailed-index.scm
index 7dc6d7c..e785164 100644
--- a/website/apps/packages/templates/detailed-index.scm
+++ b/website/apps/packages/templates/detailed-index.scm
@@ -13,8 +13,9 @@
   #:export (detailed-index-t))
 
 
-(define (detailed-index-t context)
-  "Return SHTML index page for the package app."
+(define* (detailed-index-t context #:optional total)
+  "Return SHTML index page for the package app.  TOTAL is the total number of
+packages to advertise."
   (let ((packages (context-datum context "packages")))
     (theme
      #:title (list "Packages")
@@ -43,7 +44,7 @@
 
        (p
         (@ (class "limit-width centered-block"))
-        "GNU Guix provides " ,(number* (length packages))
+        "GNU Guix provides " ,(number* (or total (length packages)))
         " packages transparently "
         (a (@ (href "https://hydra.gnu.org/jobset/gnu/master#tabs-status";))
            "available as pre-built binaries")
diff --git a/website/apps/packages/utils.scm b/website/apps/packages/utils.scm
index 8944269..a5fe83c 100644
--- a/website/apps/packages/utils.scm
+++ b/website/apps/packages/utils.scm
@@ -38,7 +38,9 @@
   #:use-module (ice-9 rdelim)
   #:use-module (ice-9 popen)
   #:use-module (web uri)
-  #:export (package-description-shtml
+  #:export (take-at-most
+
+            package-description-shtml
             package-synopsis-shtml
 
             location->ilink
@@ -54,6 +56,19 @@
 ;;; Helper procedures.
 ;;;
 
+(define (take-at-most lst max)
+  "Take up to MAX elements from LST."
+  (let loop ((lst lst)
+             (result '())
+             (total 0))
+    (match lst
+      (()
+       (reverse result))
+      ((head . tail)
+       (if (>= total max)
+           (reverse result)
+           (loop tail (cons head result) (+ 1 total)))))))
+
 (define (texinfo->shtml texi)
   "Parse TEXI, a string, and return the corresponding SHTML."
   ;; 'texi-fragment->stexi' uses 'call-with-input-string', so make sure