1 files changed, 220 insertions, 0 deletions
diff --git a/lib/doml.js b/lib/doml.js
new file mode 100644
index 0000000..332a17e
--- /dev/null
+++ b/lib/doml.js
@@ -0,0 +1,220 @@
+(function() {
+	var listFromHtmlCollection = function(collection) {
+		var lst = [];
+		for (var idx = 0; idx < collection.length; idx++) {
+			lst.push(collection[idx]);
+		}
+		return lst;
+	};
+	
+	var DomlEvaluator = function() {
+		var me = this;
+
+		// members of the Types object are functions that take a string and return
+		// an appropriate value as a native type
+		me.Types = {
+			'number': function(val) {
+				if (val.indexOf('.')) {
+					return parseFloat(val);
+				} else {
+					return parseInt(val, 10);
+				}
+			},
+
+			'string': function(val) {
+				return val;
+			},
+
+			'boolean': function(val) {
+				if (val === 'true') {
+					return true;
+				}
+				if (val === 'false') {
+					return false;
+				}
+				throw new Error('Invalid boolean value ' + val);
+			}
+		};
+
+		// members of the BinaryOperators object are functions that take two arguments
+		// and return the result of that operation
+		me.BinaryOperators = {
+			'!=': function(a, b) {
+				return a != b;
+			},
+
+			'<': function(a, b) {
+				return a < b;
+			},
+
+			'>': function(a, b) {
+				return a > b;
+			},
+
+			'-': function(a, b) {
+				return a - b;
+			},
+
+			'+': function(a, b) {
+				return a + b;
+			},
+
+			'==': function(a, b) {
+				return a == b;
+			},
+
+			'<=': function(a, b) {
+				return a <= b;
+			},
+
+			'>=': function(a, b) {
+				return a >= b;
+			}
+		};
+
+		// members of the Statements object are functions that take a dataset, children, and context
+		// and return the result of the statement
+		me.Statements = {
+			'statement-sequence': function(dataset, children, context) {
+				var retval = null;
+				children.forEach(function(child) {
+					retval = me.evaluate(child, context);
+				});
+				return retval;
+			},
+
+			'while': function(dataset, children, context) {
+				var condition = children[0];
+				var body = children[1];
+				while (me.evaluate(condition, context)) {
+					me.evaluate(body, context);
+				}
+			},
+
+			'compare': function(dataset, children, context) {
+				var operator = me.BinaryOperators[dataset.op];
+				var lhs = me.evaluate(children[0], context);
+				var rhs = me.evaluate(children[1], context);
+				var result = operator(lhs, rhs);
+				return result;
+			},
+
+			'variable': function(dataset, children, context) {
+				return context[dataset.name];
+			},
+
+			'constant': function(dataset, children, context) {
+				return me.Types[dataset.type](dataset.val);
+			},
+
+			'branch': function(dataset, children, context) {
+				if (me.evaluate(children[0], context)) {
+					return me.evaluate(children[1], context);
+				} else if (children.length > 2) {
+					return me.evaluate(children[2], context);
+				}
+			},
+
+			'assign': function(dataset, children, context) {
+				context[dataset.name] = me.evaluate(children[0], context);
+				return context[dataset.name];
+			},
+
+			'bin-op': function(dataset, children, context) {
+				var operator = me.BinaryOperators[dataset.op];
+				var lhs = me.evaluate(children[0], context);
+				var rhs = me.evaluate(children[1], context);
+				return operator(lhs, rhs);
+			},
+
+			'return': function(dataset, children, context) {
+				return me.evaluate(children[0], context);
+			},
+
+			'print': function(dataset, children, context) {
+				var args = children.map(function(child) {
+					return me.evaluate(child, context);
+				});
+				console.log.apply(this, args);
+			}
+		};
+
+		// members of the Readability object are functions which take an element
+		// and return an array of additional text nodes which should be added
+		// to enhance readability
+		me.Decorators = {
+			'assign': function(e) {
+				return [ e.dataset.name ];
+			},
+
+			'variable': function(e) {
+				return [ e.dataset.name ];
+			},
+
+			'constant': function(e) {
+				return [ e.dataset.type + '(' + e.dataset.val + ')' ];
+			},
+
+			'compare': function(e) {
+				return [ e.dataset.op ];
+			},
+
+			'bin-op': function(e) {
+				return [ e.dataset.op ];
+			}
+		};
+
+		me.evaluate = function(node, context) {
+			if (typeof context === 'undefined') {
+				context = {};
+			}
+			var value = me.Statements[node.className](node.dataset, listFromHtmlCollection(node.children), context);
+			return value;
+		};
+
+		me.appendText = function(node, text) {
+			var n = document.createElement('var');
+			n.innerText = text;
+			node.appendChild(n);
+		};
+
+		me.decorate = function(root) {
+			var classes = Object.keys(me.Decorators);
+			for (var idx = 0; idx < classes.length; idx++) {
+				var klass = classes[idx];
+				var els = listFromHtmlCollection(root.getElementsByClassName(klass));
+				els.forEach(function(el) {
+					me.Decorators[klass](el).forEach(function(text) {
+						me.appendText(el, text);
+					});
+				});
+			}
+		};
+
+		me.run = function(root) {
+			var t0 = performance.now();
+			me.evaluate(root);
+			var t1 = performance.now();
+			me.decorate(root);
+			console.debug('Evaluated DOML program in ' + (t1 - t0) + 'ms');
+		}
+	};
+
+	var Doml = {
+		Evaluator: DomlEvaluator,
+		runOnLoad: function(root) {
+			document.addEventListener('DOMContentLoaded', function() {
+				(new DomlEvaluator()).run(document.body.children[0]);
+			});
+		}
+	};
+
+	if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
+		module.exports = Doml;
+	} else if (typeof window !== 'undefined') {
+		window.Doml = Doml;
+	} else {
+		throw new Error('Unable to register Doml');
+	}
+})();
+