Part two of turning the rabbit hole inside out

core/modules/macros/view.js

@@ -0,0 +1,105 @@
+/*\
+title: $:/core/modules/macros/view.js
+type: application/javascript
+module-type: macro
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.info = {
+	name: "view",
+	dependentOnContextTiddler: true,
+	params: {
+		field: {byPos: 0, type: "text"},
+		format: {byPos: 1, type: "text"},
+		template: {byPos: 2, type: "text"}
+	}
+};
+
+exports.executeMacro = function() {
+	var tiddler = this.wiki.getTiddler(this.tiddlerTitle),
+		field = this.hasParameter("field") ? this.params.field : "title",
+		value,
+		children,
+		t,
+		childrenClone = [],
+		parents = this.parents;
+	if(tiddler) {
+		value = tiddler.fields[field];
+	} else {
+		switch(field) {
+			case "text":
+				value = "The tiddler '" + this.tiddlerTitle + "' does not exist";
+				break;
+			case "title":
+				value = this.tiddlerTitle;
+				break;
+			case "modified":
+			case "created":
+				value = new Date();
+				break;
+			default:
+				value = "Missing tiddler '" + this.tiddlerTitle + "'";
+				break;
+		}
+	}
+	switch(this.params.format) {
+		case "link":
+			if(value === undefined) {
+				return [];
+			} else {
+				var link = $tw.Tree.Macro("link",
+											{to: value},
+											[$tw.Tree.Text(value)],
+											this.wiki);
+				link.execute(parents,this.tiddlerTitle);
+				return [link];
+			}
+			break;
+		case "wikified":
+			if(tiddler && this.params.field === "text") {
+				if(parents.indexOf(tiddler.fields.title) !== -1) {
+					children = [$tw.Tree.errorNode("Tiddler recursion error in <<view>> macro")];
+				} else {
+					children = this.wiki.parseTiddler(tiddler.fields.title).tree;
+				}
+				parents = parents.slice(0);
+				parents.push(tiddler.fields.title);
+			} else {
+				children = this.wiki.parseText("text/x-tiddlywiki",value).tree;
+			}
+			for(t=0; t<children.length; t++) {
+				childrenClone.push(children[t].clone());
+			}
+			for(t=0; t<childrenClone.length; t++) {
+				childrenClone[t].execute(parents,this.tiddlerTitle);
+			}
+			return childrenClone;
+		case "date":
+			var template = this.params.template || "DD MMM YYYY";
+			if(value === undefined) {
+				return [];
+			} else {
+				return [$tw.Tree.Text($tw.utils.formatDateString(value,template))];
+			}
+			break;
+		default: // "text"
+			// Get the stringified version of the field value
+			if(field !== "text" && tiddler) {
+				value = tiddler.getFieldString(field);
+			}
+			if(value === undefined || value === null) {
+				return [];
+			} else {
+				return [$tw.Tree.Text(value)];
+			}
+	}
+	return [];
+};
+
+})();
+