Start adding support for permalinks

At this point we respect any permalink at startup, but we don’t yet
dynamically update the permalink, nor do we respond to ongoing
permalink changes.

The permalink separator being `%00` seems like it might be a bit
controversial. It buys us not having to wrap tiddler titles in double
square brackets if they contain spaces.

Another thing is that this scheme doesn’t support tiddler filters; the
plan is to support them like this:

http://tiddlywiki.com/#!Target%00%00[tag[task]sort[created]]

boot/boot.js

@@ -1621,8 +1621,15 @@ readBrowserTiddlers: whether to read tiddlers from the HTML file we're executing
 */
 $tw.boot.startup = function(options) {
 	options = options || {};
-	// Check for safe mode
-	$tw.safeMode = $tw.browser && location.hash === "#:safe";
+	// Get the URL hash and check for safe mode
+	$tw.locationHash = "#";
+	if($tw.browser) {
+		if(location.hash === "#:safe") {
+			$tw.safeMode = true;
+		} else {
+			$tw.locationHash = location.hash;
+		}
+	}
 	// Initialise some more $tw properties
 	$tw.utils.deepDefaults($tw,{
 		modules: { // Information about each module

core/modules/startup.js

@@ -18,6 +18,14 @@ var PERFORMANCE_INSTRUMENTATION = false;
 // Time (in ms) that we defer refreshing changes to draft tiddlers
 var DRAFT_TIDDLER_TIMEOUT = 400;
 
+// Default story and history lists
+var DEFAULT_STORY_TITLE = "$:/StoryList";
+var DEFAULT_HISTORY_TITLE = "$:/HistoryList";
+
+// Default tiddlers
+var DEFAULT_TIDDLERS_TITLE = "$:/DefaultTiddlers";
+		
+
 var widget = require("$:/core/modules/widgets/widget.js");
 
 exports.startup = function() {
@@ -64,26 +72,37 @@ exports.startup = function() {
 			"$:/themes/tiddlywiki/vanilla"
 		]
 	});
-	// Display the default tiddlers
-	var displayDefaultTiddlers = function() {
-		// Get the default tiddlers
-		var defaultTiddlersTitle = "$:/DefaultTiddlers",
-			defaultTiddlersTiddler = $tw.wiki.getTiddler(defaultTiddlersTitle),
-			defaultTiddlers = [];
-		if(defaultTiddlersTiddler) {
-			defaultTiddlers = $tw.wiki.filterTiddlers(defaultTiddlersTiddler.fields.text);
-		}
-		// Initialise the story
-		var storyTitle = "$:/StoryList",
-			story = [];
-		for(var t=0; t<defaultTiddlers.length; t++) {
-			story[t] = defaultTiddlers[t];
-		}
-		$tw.wiki.addTiddler({title: storyTitle, text: "", list: story},$tw.wiki.getModificationFields());
-	};
-	displayDefaultTiddlers();
 	// Clear outstanding tiddler store change events to avoid an unnecessary refresh cycle at startup
 	$tw.wiki.clearTiddlerEventQueue();
+	// Decode the hash portion of our URL
+	var parts = [];
+	if($tw.locationHash.charAt(1) === "!") {
+		parts = decodeURIComponent($tw.locationHash.substr(2)).split("\u0000")
+	}
+	if(parts[0]) {
+		// Set the history
+		var historyList = [{title: parts[0]}];
+		$tw.wiki.setTiddlerData(DEFAULT_HISTORY_TITLE, historyList, {"current-tiddler": parts[0]});
+		// Set the story
+		var story = [];
+		for(var t=1; t<parts.length; t++) {
+			if(parts[t]) {
+				story.push(parts[t]);
+			}
+		}
+		// If the story is empty use the default tiddlers
+		if(story.length === 0) {
+			story = getDefaultTiddlers();
+		}
+		// If the target tiddler isn't included then splice it in at the top
+		if(story.indexOf(parts[0]) === -1) {
+			story.unshift(parts[0]);
+		}
+		$tw.wiki.addTiddler({title: DEFAULT_STORY_TITLE, text: "", list: story},$tw.wiki.getModificationFields());
+	} else {
+		// Display the default tiddlers if the hash portion was empty
+		displayDefaultTiddlers();
+	}
 	// Set up the syncer object
 	$tw.syncer = new $tw.Syncer({wiki: $tw.wiki});
 	// Host-specific startup
@@ -248,6 +267,34 @@ exports.startup = function() {
 };
 
 
+/*
+Helper to display the default tiddlers
+*/
+function displayDefaultTiddlers() {
+	// Get the default tiddlers
+	var defaultTiddlersTitle = "$:/DefaultTiddlers",
+		defaultTiddlersTiddler = $tw.wiki.getTiddler(defaultTiddlersTitle),
+		defaultTiddlers = [];
+	if(defaultTiddlersTiddler) {
+		defaultTiddlers = $tw.wiki.filterTiddlers(defaultTiddlersTiddler.fields.text);
+	}
+	// Initialise the story
+	var story = [];
+	for(var t=0; t<defaultTiddlers.length; t++) {
+		story[t] = defaultTiddlers[t];
+	}
+	$tw.wiki.addTiddler({title: DEFAULT_STORY_TITLE, text: "", list: story},$tw.wiki.getModificationFields());
+}
+
+function getDefaultTiddlers() {
+	var defaultTiddlersTiddler = $tw.wiki.getTiddler(DEFAULT_TIDDLERS_TITLE),
+		defaultTiddlers = [];
+	if(defaultTiddlersTiddler) {
+		defaultTiddlers = $tw.wiki.filterTiddlers(defaultTiddlersTiddler.fields.text);
+	}
+	return defaultTiddlers;
+}
+
 /*
 Main render function for PageMacros, which includes the PageTemplate
 */

core/modules/storyviews/zoomin.js

@@ -15,10 +15,16 @@ Zooms between individual tiddlers
 var ZoominListView = function(listWidget) {
 	var self = this;
 	this.listWidget = listWidget;
-	// Make all the tiddlers position absolute, and hide all but the first one
+	// Get the index of the tiddler that is at the top of the history
+	var history = this.listWidget.wiki.getTiddlerData(this.listWidget.historyTitle,[]),
+		targetTiddler;
+	if(history.length > 0) {
+		targetTiddler = history[history.length-1].title;
+	}
+	// Make all the tiddlers position absolute, and hide all but the top (or first) one
 	$tw.utils.each(this.listWidget.children,function(itemWidget,index) {
 		var domNode = itemWidget.findFirstDomNode();
-		if(index) {
+		if(targetTiddler !== itemWidget.parseTreeNode.itemTitle || (!targetTiddler && index)) {
 			domNode.style.display = "none";
 		} else {
 			self.currentTiddlerDomNode = domNode;

editions/tw5.com/tiddlers/Release 5.0.11beta.tid

@@ -18,6 +18,7 @@ See [[Notes for upgrading to 5.0.11-beta]] for more details of these changes:
 
 !! Usability Improvements
 
+* Added support for PermaLinks and browser navigation buttons
 * [[Replaced|https://github.com/Jermolene/TiddlyWiki5/issues/580]] hamburger menu icon with double chevron icon
 * [[Enhance|https://github.com/Jermolene/TiddlyWiki5/commit/552657fc584dbb36754d3fcabca2cdef7e916ec9]] plain text parsing to use the CodeBlockWidget, and hence use syntax highlighting if the plugin is installed. This gives us syntax highlighting for JavaScript shadow tiddlers, amongst other things
 * Improvements to Chinese, Japanese and French translations

editions/tw5.com/tiddlers/concepts/PermaLinks.tid

@@ -0,0 +1,26 @@
+created: 20140502213500000
+modified: 20140502213500000
+tags: concepts
+title: PermaLinks
+type: text/vnd.tiddlywiki
+
+Permalinks allow direct links to individual tiddlers within a TiddlyWiki.
+
+The simplest form of permalink is a single target tiddler title appended to the base URL with "#!":
+
+http://tiddlywiki.com/#!HelloThere
+
+The tiddler title can contain spaces if required:
+
+[[http://tiddlywiki.com/#!Using TiddlyWiki on Node.js]]
+
+The permalink can also specify the story list of tiddlers that should be opened alongside the target tiddler. The tiddler titles are separated by `%00`:
+
+http://tiddlywiki.com/#!Tiddlers%00Tags%00TiddlerFields%00Tiddlers
+
+In this form, the first tiddler title is taken to be the target tiddler, and the remaining titles give the sequence of tiddlers in the story list.
+
+If the target tiddler isn't present in the story list then it is automatically inserted at the top. This means that the following two examples both target the tiddler `Tiddlers` within the story sequence `Tiddlers`, `Tags`, `TiddlerFields`:
+
+http://tiddlywiki.com/#!Tiddlers%00Tags%00TiddlerFields
+http://tiddlywiki.com/#!Tiddlers%00Tiddlers%00Tags%00TiddlerFields