创建一个简单但灵活的模板引擎 [英] Creating a simple but flexible templating engine

问题描述

我正在尝试构建一个基本的模板引擎.就像已经开源的模板引擎一样，我正在使用搜索和替换技术.

I am trying to build a basic templating engine. Like the template engines already available as open source, I am using search and replace techniques.

然而，由于搜索和替换必须是硬编码的，所以它不是那么灵活.我的意思是说，作为一个例子，我正在使用这样的东西

However, as the search and replace have to be hardcoded, it is not so much flexible. What I mean to say is, as an example, I am using something like this

$templateMarkup = '<div class="title">{_TITLE_}</div>';
$renderedMarkup = str_replace("{_TITLE_}",$title,$templateMarkup);
echo $renderedMarkup;

如您所见，它是硬编码的.所以我必须有意识地了解所有占位符才能成功渲染.

As you can see, it is hardcoded. So I have to purposely know all the placeholders to accomplish a successful render.

我在正则表达式方面有点弱.但我知道，如果我可以开发一个正则表达式，它可以匹配所有以 {_ 开头并以 _} 结尾的文本，并获得它们之间的值，我可能会能够创建灵活的模板引擎.

I am a little bit weak in regular expression. But I know, if I can develop a regex, which can match all the text starting with {_ and ending _} and get the value in between them, I just might be able to create a flexible templating engine.

我需要正则表达式方面的帮助.

I need help with the regular expression.

如果我完全走错了路，请警告我.

If I am completely going the wrong way to accomplish, please do warn me.

<子>对于那些认为我在重新发明轮子的人.这是我的解释

_{For those who think I am reinventing the wheel. Here is my explanation}

Templating engines, that are already available are quite unnecessarily complex. 
My requirements are simple and so I am builidng my own simple engine. 

推荐答案

您正在寻找的正则表达式是 {_(\w+)_}，如果您的模板标签只是一个一个字.你会像这样使用它:

The regular expression you're looking for is {_(\w+)_}, if your template tags are only ever a single word. You'd use it a bit like this:

<?php

$replacements = array(
    "firstname" => "John",
    "lastname" => "Smith"
);

$template_markup = "Hello {_firstname_} {_lastname_}";
if(preg_match_all('/{_(\w+)_}/', $template_markup, $matches)) {
    foreach($matches[1] as $m) {
        $template_markup = str_replace("{_".$m."_}", $replacements[$m], $template_markup);
    }
}
echo $template_markup;

?>

您会看到 preg_match_all 在正则表达式周围有正斜杠，这些是分隔符.

You'll see the preg_match_all has forward slashes surrounding the regular expression, these are delimiters.

更新:如果您想将正则表达式扩展到单个单词之外，那么在使用 . 匹配任何字符时要小心.最好使用类似这样的东西来指定要包含其他字符:{_([\w-_]+)_}.[\w-_] 表示它将匹配字母数字字符、连字符或下划线.

Update: If you want to expand the regular expression beyond single words, then be careful when using . to match any character. It's better to use something like this to specify that you want to include other characters: {_([\w-_]+)_}. The [\w-_] means it will match either alphanumeric characters, hyphens or underscores.

(也许有人可以解释为什么使用 . 可能是个坏主意?我不是 100% 确定).

(Perhaps someone can explain why using . might be a bad idea? I'm not 100% sure).

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