How to make a template engine without OOP?

Question

PHP

Hello, how to make a template engine without OOP. I ask for an example.
We need a template engine with tags like {username} , more precisely, that it would substitute the necessary values ​​instead of tags on the page, the template is of course in .tpl

Answer 1

I was a little bored...

function render($template, array $data = array()) {
    $content = file_get_content(sprintf('%s/templates/%s.tpl', __DIR__, $template);
    
    return preg_replace_callback('/\{\{\s*([a-z_\-][a-z0-9_\-]*)\s*(\|\s*raw\s*)?\}\}/i', function ($matches) use ($data) {
        $needToEscape = !isset($matches[2]);
        if (!isset($data[$matches[1]]) {
            throw new \Exception(sprintf('Variable "%s" not exists', $matches[1]));     
        }

        $value = $data[$matches[1]];
        if ($needToEscape) {
             // тут можно придумать чего получше, это просто для примера.
             $value = htmlentities($value);
        }

        return $value;
    }, $content);
}

Usage:

<!-- post.tpl -->
<h1>{{ title }}</h1>
{{ content | raw }}

echo render('post', ['title' => 'Some Title', 'content' => 'Some <strong>content with html</strong>!']);

Answer 2

PHP itself is a templating engine.
Or formulate the question more clearly.

Answer 3

function renderTpl($tpl, $data) {
  return preg_replace_callback(
    "@\{(.+?)\}@", 
    function($matches) use ($data) {
      return isset($data[$matches[1]]) ? $data[$matches[1]] : "";
    }, 
    $tpl
  );
}

$template = "Hello {first_name} {last_name}!!!";

$data = array(
  "first_name" => "John",
  "last_name" => "Doe"
);

echo renderTpl($template, $data); //Hello John Doe!!!