From b7cddc31729ceb349cac6a6544db782d92a497df Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 4 Jul 2017 14:10:07 +0200
Subject: [PATCH 1/8] Doc: Indicate the language

---
 Doc/tools/templates/layout.html | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Doc/tools/templates/layout.html b/Doc/tools/templates/layout.html
index 640d8b30493299..e9b305d334f123 100644
--- a/Doc/tools/templates/layout.html
+++ b/Doc/tools/templates/layout.html
@@ -4,6 +4,7 @@
                  style="vertical-align: middle; margin-top: -1px"/></li>
         <li><a href="https://www.python.org/">Python</a>{{ reldelim1 }}</li>
         <li>
+          <span class="language_switcher_placeholder">{{ language or 'en' }}</span>
           {%- if versionswitcher is defined %}
           <span class="version_switcher_placeholder">{{ release }}</span>
           <a href="{{ pathto('index') }}">{% trans %}Documentation {% endtrans %}</a>{{ reldelim1 }}

From 7f74c22ace7b7a514361bd68d56c93b931e24ba6 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 11 Jul 2017 00:19:48 +0200
Subject: [PATCH 2/8] Renaming version_switcher to switchers (to add
 language_switcher).

---
 Doc/Makefile                                         | 4 ++--
 Doc/tools/static/{version_switch.js => switchers.js} | 0
 Doc/tools/templates/layout.html                      | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
 rename Doc/tools/static/{version_switch.js => switchers.js} (100%)

diff --git a/Doc/Makefile b/Doc/Makefile
index ae59f3294f1c06..526269d1e19d9e 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -167,12 +167,12 @@ serve:
 
 # for development releases: always build
 autobuild-dev:
-	make dist SPHINXOPTS='$(SPHINXOPTS) -Ea -A daily=1 -A versionswitcher=1'
+	make dist SPHINXOPTS='$(SPHINXOPTS) -Ea -A daily=1 -A switchers=1'
 	-make suspicious
 
 # for quick rebuilds (HTML only)
 autobuild-dev-html:
-	make html SPHINXOPTS='$(SPHINXOPTS) -Ea -A daily=1 -A versionswitcher=1'
+	make html SPHINXOPTS='$(SPHINXOPTS) -Ea -A daily=1 -A switchers=1'
 
 # for stable releases: only build if not in pre-release stage (alpha, beta)
 # release candidate downloads are okay, since the stable tree can be in that stage
diff --git a/Doc/tools/static/version_switch.js b/Doc/tools/static/switchers.js
similarity index 100%
rename from Doc/tools/static/version_switch.js
rename to Doc/tools/static/switchers.js
diff --git a/Doc/tools/templates/layout.html b/Doc/tools/templates/layout.html
index e9b305d334f123..c2106678ac60f4 100644
--- a/Doc/tools/templates/layout.html
+++ b/Doc/tools/templates/layout.html
@@ -4,8 +4,8 @@
                  style="vertical-align: middle; margin-top: -1px"/></li>
         <li><a href="https://www.python.org/">Python</a>{{ reldelim1 }}</li>
         <li>
+          {%- if switchers is defined %}
           <span class="language_switcher_placeholder">{{ language or 'en' }}</span>
-          {%- if versionswitcher is defined %}
           <span class="version_switcher_placeholder">{{ release }}</span>
           <a href="{{ pathto('index') }}">{% trans %}Documentation {% endtrans %}</a>{{ reldelim1 }}
           {%- else %}
@@ -42,7 +42,7 @@
     <link rel="canonical" href="https://docs.python.org/3/{{pagename}}.html" />
     {% if builder != "htmlhelp" %}
     {% if not embedded %}<script type="text/javascript" src="{{ pathto('_static/copybutton.js', 1) }}"></script>{% endif %}
-    {% if versionswitcher is defined and not embedded %}<script type="text/javascript" src="{{ pathto('_static/version_switch.js', 1) }}"></script>{% endif %}
+    {% if switchers is defined and not embedded %}<script type="text/javascript" src="{{ pathto('_static/switchers.js', 1) }}"></script>{% endif %}
     {% if pagename == 'whatsnew/changelog' and not embedded %}
     <script type="text/javascript">
       $(document).ready(function() {

From 21b7719d8a724c1e7baaf2bdbaaddec987572423 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 11 Jul 2017 01:13:06 +0200
Subject: [PATCH 3/8] Adding language switch.

---
 Doc/tools/static/switchers.js | 108 ++++++++++++++++++++++++++--------
 1 file changed, 82 insertions(+), 26 deletions(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 8b36a61671831d..930d8c0e20c96c 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -10,7 +10,12 @@
     '2.7': '2.7',
   };
 
-  function build_select(current_version, current_release) {
+  var all_languages = {
+      'en': 'English',
+      'fr': 'Français',
+  };
+
+  function build_version_select(current_version, current_release) {
     var buf = ['<select>'];
 
     $.each(all_versions, function(version, title) {
@@ -25,43 +30,94 @@
     return buf.join('');
   }
 
-  function patch_url(url, new_version) {
-    var url_re = /\.org\/(\d|py3k|dev|((release\/)?\d\.\d[\w\d\.]*))\//,
-        new_url = url.replace(url_re, '.org/' + new_version + '/');
+  function build_language_select(current_language) {
+    var buf = ['<select>'];
 
-    if (new_url == url && !new_url.match(url_re)) {
-      // python 2 url without version?
-      new_url = url.replace(/\.org\//, '.org/' + new_version + '/');
-    }
-    return new_url;
+    $.each(all_languages, function(language, title) {
+      if (language == current_language)
+        buf.push('<option value="' + language + '" selected="selected">' +
+                 all_languages[current_language] + '</option>');
+      else
+        buf.push('<option value="' + language + '">' + title + '</option>');
+    });
+    buf.push('</select>');
+    return buf.join('');
   }
 
-  function on_switch() {
-    var selected = $(this).children('option:selected').attr('value');
+  function naviagate_if_exists(url, default_url) {
+    // check beforehand if url exists, else redirect to default_url.
+    $.ajax({
+      url: url,
+      success: function() {
+         window.location.href = url;
+      },
+      error: function() {
+         window.location.href = default_url;
+      }
+    });
+  }
 
-    var url = window.location.href,
-        new_url = patch_url(url, selected);
+  function on_version_switch() {
+    var selected_version = $(this).children('option:selected').attr('value') + '/';
+    var url = window.location.href;
+    var current_language = find_language_in_url(url);
+    var current_version = find_version_in_url(url);
+    var new_url = url.replace('.org/' + current_language + current_version,
+                              '.org/' + current_language + selected_version);
+    if (new_url != url) {
+      naviagate_if_exists(new_url, 'https://docs.python.org/' +
+                          current_language + selected_version);
+    }
+  }
 
+  function on_language_switch() {
+    var selected_language = $(this).children('option:selected').attr('value') + '/';
+    var url = window.location.href;
+    var current_language = find_language_in_url(url);
+    var current_version = find_version_in_url(url);
+    if (selected_language == 'en/') // Special 'default' case for english.
+      selected_language = '';
+    var new_url = url.replace('.org/' + current_language + current_version,
+                              '.org/' + selected_language + current_version);
     if (new_url != url) {
-      // check beforehand if url exists, else redirect to version's start page
-      $.ajax({
-        url: new_url,
-        success: function() {
-           window.location.href = new_url;
-        },
-        error: function() {
-           window.location.href = 'https://docs.python.org/' + selected;
-        }
-      });
+      naviagate_if_exists(new_url, 'https://docs.python.org/' +
+                          selected_language + current_version);
     }
   }
 
+  // Returns the path segment as a string, like 'fr/' or '' if not found.
+  function find_language_in_url(url) {
+    var language_regexp = '\.org/(' + Object.keys(all_languages).join('|') + '/)';
+    var match = url.match(language_regexp);
+    if (match !== null)
+        return match[1];
+    return '';
+  }
+
+  // Returns the path segment as a string, like '3.6/' or '' if not found.
+  function find_version_in_url(url) {
+    var language_segment = '(?:(?:' + Object.keys(all_languages).join('|') + ')/)';
+    var version_segment = '(?:(?:\\d|py3k|dev|(?:(?:release/)?\\d\\.\\d[\\w\\d\\.]*))/)';
+    var version_regexp = '\\.org/' + language_segment + '?(' + version_segment + ')';
+    var match = url.match(version_regexp);
+    if (match !== null)
+      return match[1];
+    return ''
+  }
+
   $(document).ready(function() {
     var release = DOCUMENTATION_OPTIONS.VERSION;
+    var current_language = find_language_in_url(window.location.href).replace(
+            /\/+$/g, '') || 'en';
     var version = release.substr(0, 3);
-    var select = build_select(version, release);
+    var version_select = build_version_select(version, release);
+
+    $('.version_switcher_placeholder').html(version_select);
+    $('.version_switcher_placeholder select').bind('change', on_version_switch);
+
+    var language_select = build_language_select(current_language);
 
-    $('.version_switcher_placeholder').html(select);
-    $('.version_switcher_placeholder select').bind('change', on_switch);
+    $('.language_switcher_placeholder').html(language_select);
+    $('.language_switcher_placeholder select').bind('change', on_language_switch);
   });
 })();

From e12dd3202300a4cba43e41f1c4f3fca6907b92d9 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 11 Jul 2017 10:29:24 +0200
Subject: [PATCH 4/8] Doc switchers: Enhance readability of regex parsing
 versions.

---
 Doc/tools/static/switchers.js | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 930d8c0e20c96c..225611b4535b7f 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -1,6 +1,15 @@
 (function() {
   'use strict';
 
+  // Parses versions in URL segments like:
+  // "/3", "/dev", "/release/2.7" or "/3.6rc2"
+  var version_regexs = [
+    '(?:\\d)',
+    '(?:\\d\\.\\d[\\w\\d\\.]*)',
+    '(?:py3k)',
+    '(?:dev)',
+    '(?:release/\\d.\\d[\\x\\d\\.]*)'];
+
   var all_versions = {
     '3.7': 'dev (3.7)',
     '3.6': '3.6',
@@ -97,7 +106,7 @@
   // Returns the path segment as a string, like '3.6/' or '' if not found.
   function find_version_in_url(url) {
     var language_segment = '(?:(?:' + Object.keys(all_languages).join('|') + ')/)';
-    var version_segment = '(?:(?:\\d|py3k|dev|(?:(?:release/)?\\d\\.\\d[\\w\\d\\.]*))/)';
+    var version_segment = '(?:(?:' + version_regexs.join('|') + ')/)';
     var version_regexp = '\\.org/' + language_segment + '?(' + version_segment + ')';
     var match = url.match(version_regexp);
     if (match !== null)

From 6f450c7656fd463fcf3340baf03a3385fd64c2ae Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 11 Jul 2017 10:35:19 +0200
Subject: [PATCH 5/8] Doc switchers: Desambiguate the need of a
 replace(/\/+$/g, '') by proper naming.

---
 Doc/tools/static/switchers.js | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 225611b4535b7f..45fa8ceb51d11f 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -69,8 +69,8 @@
   function on_version_switch() {
     var selected_version = $(this).children('option:selected').attr('value') + '/';
     var url = window.location.href;
-    var current_language = find_language_in_url(url);
-    var current_version = find_version_in_url(url);
+    var current_language = language_segment_from_url(url);
+    var current_version = version_segment_in_url(url);
     var new_url = url.replace('.org/' + current_language + current_version,
                               '.org/' + current_language + selected_version);
     if (new_url != url) {
@@ -82,8 +82,8 @@
   function on_language_switch() {
     var selected_language = $(this).children('option:selected').attr('value') + '/';
     var url = window.location.href;
-    var current_language = find_language_in_url(url);
-    var current_version = find_version_in_url(url);
+    var current_language = language_segment_from_url(url);
+    var current_version = version_segment_in_url(url);
     if (selected_language == 'en/') // Special 'default' case for english.
       selected_language = '';
     var new_url = url.replace('.org/' + current_language + current_version,
@@ -94,8 +94,9 @@
     }
   }
 
-  // Returns the path segment as a string, like 'fr/' or '' if not found.
-  function find_language_in_url(url) {
+  // Returns the path segment of the language as a string, like 'fr/'
+  // or '' if not found.
+  function language_segment_from_url(url) {
     var language_regexp = '\.org/(' + Object.keys(all_languages).join('|') + '/)';
     var match = url.match(language_regexp);
     if (match !== null)
@@ -103,8 +104,9 @@
     return '';
   }
 
-  // Returns the path segment as a string, like '3.6/' or '' if not found.
-  function find_version_in_url(url) {
+  // Returns the path segment of the version as a string, like '3.6/'
+  // or '' if not found.
+  function version_segment_in_url(url) {
     var language_segment = '(?:(?:' + Object.keys(all_languages).join('|') + ')/)';
     var version_segment = '(?:(?:' + version_regexs.join('|') + ')/)';
     var version_regexp = '\\.org/' + language_segment + '?(' + version_segment + ')';
@@ -116,8 +118,8 @@
 
   $(document).ready(function() {
     var release = DOCUMENTATION_OPTIONS.VERSION;
-    var current_language = find_language_in_url(window.location.href).replace(
-            /\/+$/g, '') || 'en';
+    var language_segment = language_segment_from_url(window.location.href);
+    var current_language = language_segment.replace(/\/+$/g, '') || 'en';
     var version = release.substr(0, 3);
     var version_select = build_version_select(version, release);
 

From 2e8eb7fc39174c23a9f135682abd2128a628fd89 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Wed, 26 Jul 2017 14:03:20 +0200
Subject: [PATCH 6/8] Doc switchers: py3k can't reach js, it's redirected
 server-side by nginx.

---
 Doc/tools/static/switchers.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 45fa8ceb51d11f..69235fea189a7c 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -6,7 +6,6 @@
   var version_regexs = [
     '(?:\\d)',
     '(?:\\d\\.\\d[\\w\\d\\.]*)',
-    '(?:py3k)',
     '(?:dev)',
     '(?:release/\\d.\\d[\\x\\d\\.]*)'];
 

From c14cc52f9a8ff6ac3ac0a837c089953b53f574df Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Wed, 26 Jul 2017 14:05:17 +0200
Subject: [PATCH 7/8] Doc switchers: Examples matching actual regexes.

---
 Doc/tools/static/switchers.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 69235fea189a7c..9e97793bc7cc07 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -2,7 +2,7 @@
   'use strict';
 
   // Parses versions in URL segments like:
-  // "/3", "/dev", "/release/2.7" or "/3.6rc2"
+  // "3", "dev", "release/2.7" or "3.6rc2"
   var version_regexs = [
     '(?:\\d)',
     '(?:\\d\\.\\d[\\w\\d\\.]*)',

From da7a03450217406c212eedbfdb2697c9d9183b92 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Mon, 31 Jul 2017 00:26:23 +0200
Subject: [PATCH 8/8] Doc switchers: Better fallback on unexisting translated
 version.

---
 Doc/tools/static/switchers.js | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/Doc/tools/static/switchers.js b/Doc/tools/static/switchers.js
index 9e97793bc7cc07..470ff6d33b72b9 100644
--- a/Doc/tools/static/switchers.js
+++ b/Doc/tools/static/switchers.js
@@ -52,15 +52,20 @@
     return buf.join('');
   }
 
-  function naviagate_if_exists(url, default_url) {
-    // check beforehand if url exists, else redirect to default_url.
+  function navigate_to_first_existing(urls) {
+    // Navigate to the first existing URL in urls.
+    var url = urls.shift();
+    if (urls.length == 0) {
+      window.location.href = url;
+      return;
+    }
     $.ajax({
       url: url,
       success: function() {
-         window.location.href = url;
+        window.location.href = url;
       },
       error: function() {
-         window.location.href = default_url;
+        navigate_to_first_existing(urls);
       }
     });
   }
@@ -73,8 +78,14 @@
     var new_url = url.replace('.org/' + current_language + current_version,
                               '.org/' + current_language + selected_version);
     if (new_url != url) {
-      naviagate_if_exists(new_url, 'https://docs.python.org/' +
-                          current_language + selected_version);
+      navigate_to_first_existing([
+        new_url,
+        url.replace('.org/' + current_language + current_version,
+                    '.org/' + selected_version),
+        'https://docs.python.org/' + current_language + selected_version,
+        'https://docs.python.org/' + selected_version,
+        'https://docs.python.org/'
+      ]);
     }
   }
 
@@ -88,8 +99,10 @@
     var new_url = url.replace('.org/' + current_language + current_version,
                               '.org/' + selected_language + current_version);
     if (new_url != url) {
-      naviagate_if_exists(new_url, 'https://docs.python.org/' +
-                          selected_language + current_version);
+      navigate_to_first_existing([
+        new_url,
+        'https://docs.python.org/'
+      ]);
     }
   }