Update savers to specify variables, including filename

Now the `tm-download-file` and `tm-save-file` messages use the hashmap
to specify variables to be applied when rendering the tiddler.

We also add a convention that the variable “filename” is used to
specify a filename for the download.

core/modules/saver-handler.js

@@ -89,14 +89,16 @@ function SaverHandler(options) {
 		$tw.rootWidget.addEventListener("tm-save-wiki",function(event) {
 			self.saveWiki({
 				template: event.param,
-				downloadType: "text/plain"
+				downloadType: "text/plain",
+				variables: event.paramObject
 			});
 		});
 		$tw.rootWidget.addEventListener("tm-download-file",function(event) {
 			self.saveWiki({
 				method: "download",
 				template: event.param,
-				downloadType: "text/plain"
+				downloadType: "text/plain",
+				variables: event.paramObject
 			});
 		});
 	}
@@ -143,9 +145,10 @@ SaverHandler.prototype.saveWiki = function(options) {
 	options = options || {};
 	var self = this,
 		method = options.method || "save",
+		variables = options.variables || {},
 		template = options.template || "$:/core/save/all",
 		downloadType = options.downloadType || "text/plain",
-		text = this.wiki.renderTiddler(downloadType,template),
+		text = this.wiki.renderTiddler(downloadType,template,options),
 		callback = function(err) {
 			if(err) {
 				alert("Error while saving:\n\n" + err);
@@ -168,7 +171,7 @@ SaverHandler.prototype.saveWiki = function(options) {
 	// Call the highest priority saver that supports this method
 	for(var t=this.savers.length-1; t>=0; t--) {
 		var saver = this.savers[t];
-		if(saver.info.capabilities.indexOf(method) !== -1 && saver.save(text,method,callback)) {
+		if(saver.info.capabilities.indexOf(method) !== -1 && saver.save(text,method,callback,{variables: {filename: variables.filename}})) {
 			this.logger.log("Saving wiki with method",method,"through saver",saver.info.name);
 			return true;
 		}

core/modules/savers/download.js

@@ -18,12 +18,17 @@ Select the appropriate saver module and set it up
 var DownloadSaver = function(wiki) {
 };
 
-DownloadSaver.prototype.save = function(text,method,callback) {
+DownloadSaver.prototype.save = function(text,method,callback,options) {
+	options = options || {};
 	// Get the current filename
-	var filename = "tiddlywiki.html",
+	var filename = options.variables.filename;
-		p = document.location.pathname.lastIndexOf("/");
+	if(!filename) {
-	if(p !== -1) {
+		var p = document.location.pathname.lastIndexOf("/");
-		filename = document.location.pathname.substr(p+1);
+		if(p !== -1) {
+			filename = document.location.pathname.substr(p+1);
+		} else {
+			filename = "tiddlywiki.html";
+		}
 	}
 	// Set up the link
 	var link = document.createElement("a");

editions/prerelease/tiddlers/WidgetMessage_ tm-download-file.tid

@@ -0,0 +1,16 @@
+created: 20140811112201235
+modified: 20141110133723696
+tags: Messages
+title: WidgetMessage: tm-download-file
+type: text/vnd.tiddlywiki
+caption: tm-download-file
+
+The download file message causes the current saver module to prompt the user to download the result of parsing a specified template tiddler as a file. It requires the following properties on the `event` object:
+
+|!Name |!Description |
+|param |Title of a tiddler to use as a template for the new tiddler |
+|paramObject |Optional hashmap of variable values to use for the rendering |
+
+The download file message is usually generated with the ButtonWidget.
+
+The download file message is handled by the TiddlyWiki core SyncMechanism which invokes the current [[SaverModule|SaverModules]].

editions/prerelease/tiddlers/WidgetMessage_ tm-save-wiki.tid

@@ -0,0 +1,16 @@
+created: 20140811112325641
+modified: 20141110133723696
+tags: Messages
+title: WidgetMessage: tm-save-wiki
+type: text/vnd.tiddlywiki
+caption: tm-save-wiki
+
+The save wiki message causes the current saver module to perform a full save operation. The save operation can involve user interaction. It requires the following properties on the `event` object:
+
+|!Name |!Description |
+|param |Title of a tiddler to use as a template for rendering the wiki (defaults to `$:/core/save/all`) |
+|paramObject |Optional hashmap of variable values to use for the rendering |
+
+The save wiki message is usually generated by the ButtonWidget.
+
+The save wiki message is handled by the TiddlyWiki core SyncMechanism which invokes the current [[SaverModule|SaverModules]].