underScore JS 的template 转化成独立的函数

[mishe]

function template(text, data) {
    var settings = {
            evaluate    : /<%([\s\S]+?)%>/g,
            interpolate : /<%=([\s\S]+?)%>/g,
            escape      : /<%-([\s\S]+?)%>/g
        },
        noMatch = /(.)^/,
        escapes = {
            "'":      "'",
            '\\':     '\\',
            '\r':     'r',
            '\n':     'n',
            '\u2028': 'u2028',
            '\u2029': 'u2029'
        },
        escaper = /\\|'|\r|\n|\u2028|\u2029/g,
        escapeChar = function(match) {
            return '\\' + escapes[match];
        },
        matcher = RegExp([
            (settings.escape || noMatch).source,
            (settings.interpolate || noMatch).source,
            (settings.evaluate || noMatch).source
        ].join('|') + '|$', 'g'),
        index = 0,
        source = "__p+='";
    text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
        source += text.slice(index, offset).replace(escaper, escapeChar);
        index = offset + match.length;
        if (escape) {
            source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
        } else if (interpolate) {
            source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
        } else if (evaluate) {
            source += "';\n" + evaluate + "\n__p+='";
        }
        return match;
    });
    source += "';\n";
    if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
    source = "var __t,__p='',__j=Array.prototype.join," +
        "print=function(){__p+=__j.call(arguments,'');};\n" +
        source + 'return __p;\n';
    try {
        var render = new Function(settings.variable || 'obj', '_', source);
    } catch (e) {
        e.source = source;
        throw e;
    }
    var template = function(data) {
        return render.call(this, data, "");
    };

    if(data) return render(data);
    var argument = settings.variable || 'obj';
    template.source = 'function(' + argument + '){\n' + source + '}';
    return template;
};