Pre parse underscore JS templates with PHP

test.php

<?php
$string = '
	<div class="page-nav-header">
		<h1>Compose</h1>
		<ul class="nav nav-tabs">
			<li id="type-email"<%= compose_type == \'email\' ? \' class="active"\' : \'\' %>><a href="#" class="email change-type-email">E-mail</a></li>
			<li id="type-twitter"<%= compose_type == \'twitter\' ? \' class="active"\' : \'\' %>><a href="#" class="twitter change-type-twitter">Twitter</a></li>
		</ul>
		<br clear="all" />
	</div>

	<form class="form-horizontal">
		<fieldset>
			
			<legend id="form-title"></legend>
			
			<div class="control-group fields-email">
				<label class="control-label" for="field-to">To:</label>
				<div class="controls">
					<input type="text" name="to" id="field-to" class="input-xxlarge" />
				</div>
			</div>
			<div class="control-group fields-email">
				<label class="control-label" for="field-subject">Subject:</label>
				<div class="controls">
					<input type="text" name="subject" id="field-subject" class="input-xxlarge" />
				</div>
			</div>
		
		</fieldset>
		<fieldset>	
			
			<legend class="spacer fields-email">&nbsp;</legend>
			
			<div class="control-group">
				<div class="avatar"><label for="field-body"><img src="http://www.gravatar.com/" alt="" /></label></div>
				<div class="controls">
					<textarea name="body" class="input-xxlarge" id="field-body"></textarea>
				</div>
			</div>
			
			<div class="form-actions">
				<input type="submit" class="btn btn-success btn-large" value="Post" id="field-submit" /> <a href="/inbox" class="btn btn-large open_inbox">Cancel</a>
			</div>
		</fieldset>
	</form>

';

$string = str_replace(array("\t", "\n"), array("\\t", "\\n"), $string);

$templateSettings = array(
    'evaluate'		=> "/<%([\s\S]+?)%>/", 
    'interpolate'	=> "/<%=([\s\S]+?)%>/",
	'escape'		=> "/<%-([\s\S]+?)%>/"
);

$unescape = function($code) {
    return str_replace("\\'", "'", str_replace("\\\\", "\\", $code));
};

$string = preg_replace("/\\\/", "\\\\", $string);
$string = preg_replace("/'/", "\\'", $string);

$string = preg_replace_callback($templateSettings['escape'], function($match) use ($unescape) {
	return "',_.escape(" . $unescape($match[1]) . "),'";
}, $string);
$string = preg_replace_callback($templateSettings['interpolate'], function($match) use ($unescape) {	
	return "'," . $unescape($match[1]) . ",'";
}, $string);
$string = preg_replace_callback($templateSettings['evaluate'], function($match) use ($unescape) {
	return "');" . preg_replace("/[\r\n\t]/", " ", $unescape($match[1])) . ";__p.push('";
}, $string);
$string = preg_replace("/\r/", "\\r", $string);
$string = preg_replace("/\n/", "\\n", $string);
$string = preg_replace("/\t/", "\\t", $string);

$tmpl = "var __p=[],print=function(){__p.push.apply(__p,arguments);};with(obj||{}){__p.push('" . $string . "');}return __p.join('');";

echo $tmpl . PHP_EOL;

$expected = 'var __p=[],print=function(){__p.push.apply(__p,arguments);};with(obj||{}){__p.push(\'\n\t<div class="page-nav-header">\n\t\t<h1>Compose</h1>\n\t\t<ul class="nav nav-tabs">\n\t\t\t<li id="type-email"\', compose_type == \'email\' ? \' class="active"\' : \'\' ,\'><a href="#" class="email change-type-email">E-mail</a></li>\n\t\t\t<li id="type-twitter"\', compose_type == \'twitter\' ? \' class="active"\' : \'\' ,\'><a href="#" class="twitter change-type-twitter">Twitter</a></li>\n\t\t</ul>\n\t\t<br clear="all" />\n\t</div>\n\n\t<form class="form-horizontal">\n\t\t<fieldset>\n\t\t\t\n\t\t\t<legend id="form-title"></legend>\n\t\t\t\n\t\t\t<div class="control-group fields-email">\n\t\t\t\t<label class="control-label" for="field-to">To:</label>\n\t\t\t\t<div class="controls">\n\t\t\t\t\t<input type="text" name="to" id="field-to" class="input-xxlarge" />\n\t\t\t\t</div>\n\t\t\t</div>\n\t\t\t<div class="control-group fields-email">\n\t\t\t\t<label class="control-label" for="field-subject">Subject:</label>\n\t\t\t\t<div class="controls">\n\t\t\t\t\t<input type="text" name="subject" id="field-subject" class="input-xxlarge" />\n\t\t\t\t</div>\n\t\t\t</div>\n\t\t\n\t\t</fieldset>\n\t\t<fieldset>\t\n\t\t\t\n\t\t\t<legend class="spacer fields-email">&nbsp;</legend>\n\t\t\t\n\t\t\t<div class="control-group">\n\t\t\t\t<div class="avatar"><label for="field-body"><img src="http://www.gravatar.com/" alt="" /></label></div>\n\t\t\t\t<div class="controls">\n\t\t\t\t\t<textarea name="body" class="input-xxlarge" id="field-body"></textarea>\n\t\t\t\t</div>\n\t\t\t</div>\n\t\t\t\n\t\t\t<div class="form-actions">\n\t\t\t\t<input type="submit" class="btn btn-success btn-large" value="Post" id="field-submit" /> <a href="/inbox" class="btn btn-large open_inbox">Cancel</a>\n\t\t\t</div>\n\t\t</fieldset>\n\t</form>\n\n\');}return __p.join(\'\');';

echo $expected . PHP_EOL;

var_dump($expected === $tmpl);

for($i = 0; $i < strlen($expected); $i++) {
	if($expected{$i} != $tmpl{$i}) {
		echo substr($expected, $i - 30, 60) . "<--" . PHP_EOL;
		echo substr($tmpl, $i - 30, 60) . "<--" . PHP_EOL;
		
		die("Error " . $i);
	}
}
?>