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<style type="text/css">
.pass {
	background-color: #bfb;
}

.fail {
	background-color: #fbb;
}
</style>

<script type="text/javascript">
(function() {
	/** Deletes whitespace from the front and end of the given string. */
	if (typeof(String.prototype.trim) === "undefined") {
		String.prototype.trim = function() {
			var result = this;
			for (var k = 0; k < result.length && result.charAt(k) <= " "; k++) {}
			var result = result.substring(k, result.length);

			for (var j = result.length - 1; j >= 0 && result.charAt(j) <= " "; j--) {}
			result = result.substring(0, j + 1);
			return result;
		};
	}


	var LENIENT = true;

	var SPACE = " ";
	if (LENIENT) {
		SPACE = "[ \t]+";
	}

	var REGEXES = [];

	REGEXES["<dp>"] = "(the|a)";
	REGEXES["<n>"] = "(dog|cat|man|university|father|mother|child|television)";
	REGEXES["<pn>"] = "(John|Jane|Sally|Spot|Fred|Elmo)";
	REGEXES["<tv>"] = "(hit|honored|kissed|helped)";
	REGEXES["<iv>"] = "(died|collapsed|laughed|wept)";
	REGEXES["<adj>"] = "(big|fat|green|wonderful|faulty|subliminal|pretentious)";

	REGEXES["<adjp>"] = "(" + REGEXES["<adj>"] + "(" + SPACE + REGEXES["<adj>"] + ")*)";

	REGEXES["<np>"] = "((" + REGEXES["<dp>"] + SPACE + REGEXES["<adjp>"] + SPACE +
			REGEXES["<n>"] + ")" + "|" + REGEXES["<pn>"] + ")";

	REGEXES["<vp>"] = "(((" + REGEXES["<tv>"] +
			SPACE + REGEXES["<np>"] + "))" +
			"|" + REGEXES["<iv>"] + ")";

	REGEXES["<s>"] = REGEXES["<np>"] + SPACE + REGEXES["<vp>"];


	window.addEventListener("load", function() {
		document.getElementById("output").addEventListener("change", delayedCheckOutput);
		document.getElementById("output").addEventListener("keyup", delayedCheckOutput);
		document.getElementById("output").addEventListener("focus", delayedCheckOutput);
		document.getElementById("output").addEventListener("blur", delayedCheckOutput);
		document.getElementById("symbol").addEventListener("change", checkOutput);

		document.getElementById("evaluate").addEventListener("click", expressionEvaluate);
		document.getElementById("expression").addEventListener("keyup", delayedExpressionEvaluate);
		document.getElementById("expression").addEventListener("focus", delayedExpressionEvaluate);
		document.getElementById("expression").addEventListener("blur", delayedExpressionEvaluate);
		document.getElementById("expression").addEventListener("change", delayedExpressionEvaluate);

		checkOutput();
	});

	function delayedCheckOutput(event) {
		setTimeout(checkOutput, 20);
	}

	function delayedExpressionEvaluate(event) {
		setTimeout(expressionEvaluate, 20);
	}

	function checkOutput(event) {
		var regex = REGEXES[document.getElementById("symbol").value];

		var pass = true;
		var lines = document.getElementById("output").value.trim().split(/\r?\n/);
		for (var i = 0; i < lines.length && pass; i++) {
			var line = lines[i];
			if (LENIENT) {
				line = line.trim();

				// remove numbers from start of lines
				if (line.match(/^[0-9]+: /)) {
					line = line.replace(/^[0-9]+: /, "");
				}
			}
			if (!line) {   // skip blank lines
				continue;
			}

			pass = pass && line.match(new RegExp("^" + regex + "$"));
		}

		document.getElementById("output").className = pass ? "pass" : "fail";
		document.getElementById("resultmessage").innerHTML = (pass ? "pass" : "fail");
	}

	function expressionEvaluate(event) {
		var expr = document.getElementById("expression").value.trim();
		// F1::=   sin    | cos|    tan  |sqrt   | abs
		// F2::=max         |min       |   pow
		expr = expr.replace(/sin/g, "Math.sin");
		expr = expr.replace(/cos/g, "Math.cos");
		expr = expr.replace(/tan/g, "Math.tan");
		expr = expr.replace(/sqrt/g, "Math.sqrt");
		expr = expr.replace(/abs/g, "Math.abs");
		expr = expr.replace(/max/g, "Math.max");
		expr = expr.replace(/min/g, "Math.min");
		expr = expr.replace(/pow/g, "Math.pow");

		// variables that can be used in the expressions
		var x = 1;
		var y = 2;

		try {
			var result = eval(expr);
			document.getElementById("expressionresult").innerHTML = ("pass: " + result);
			document.getElementById("expression").className = "pass";
		} catch (e) {
			document.getElementById("expressionresult").innerHTML = ("fail: " + e);
			document.getElementById("expression").className = "fail";
		}
	}
})();
</script>


<h2>CS 106B/X Grammar Verifier</h2>

<p>
	Paste your <code>sentence.txt</code> output line(s) below to see whether they match the format required by the grammar.
</p>

<div>
	<fieldset style="width: 10em; margin-bottom: 1em; margin-right: 2em; float: left;">
		<legend>Symbol:</legend>
		<select id="symbol" size="10" style="width: 7em">
			<option value="&lt;s&gt;" selected="selected">&lt;s&gt;</option>
			<option value="&lt;np&gt;">&lt;np&gt;</option>
			<option value="&lt;dp&gt;">&lt;dp&gt;</option>
			<option value="&lt;adjp&gt;">&lt;adjp&gt;</option>
			<option value="&lt;adj&gt;">&lt;adj&gt;</option>
			<option value="&lt;n&gt;">&lt;n&gt;</option>
			<option value="&lt;pn&gt;">&lt;pn&gt;</option>
			<option value="&lt;vp&gt;">&lt;vp&gt;</option>
			<option value="&lt;tv&gt;">&lt;tv&gt;</option>
			<option value="&lt;iv&gt;">&lt;iv&gt;</option>
		</select>
	</fieldset>

	<fieldset style="margin-bottom: 1em; float: left;">
		<legend>Your <code>grammarGenerate</code> output:</legend>
		<textarea id="output" rows="15" cols="80" wrap="off">Elmo wept
Jane kissed Fred
</textarea> <br/>
		<span id="resultmessage">pass</span>
	</fieldset>
</div>

<p style="clear: left; padding-top: 2em">
	Expression evaluator: Paste your expressions.txt <code>E</code> output below to evaluate it to see whether you have created a legal expression.
</p>

<div>
	<input id="expression" type="text" size="100" />
	<button id="evaluate">Evaluate</button> <br />
	<span id="expressionresult">&nbsp;</span>
</div>

<script src="js/grammarverifier.js" type="text/javascript"></script>


<!-- not including common HW footer text -->

		</div> <!-- mainarea -->
	</body>
</html>