Calling PHP functions within HEREDOC strings

If you really want to do this but a bit simpler than using a class you can use:

function fn($data) {
  return $data;
}
$fn = 'fn';

$my_string = <<<EOT
Number of seconds since the Unix Epoch: {$fn(time())}
EOT;

I would not use HEREDOC at all for this, personally. It just doesn't make for a good "template building" system. All your HTML is locked down in a string which has several disadvantages

No option for WYSIWYG
No code completion for HTML from IDEs
Output (HTML) locked to logic files
You end up having to use hacks like what you're trying to do now to achieve more complex templating, such as looping

Get a basic template engine, or just use PHP with includes - it's why the language has the <?php and ?> delimiters.

template_file.php

<html>
<head>
  <title><?php echo $page_title; ?></title>
</head>
<body>
  <?php echo getPageContent(); ?>
</body>

index.php

<?php

$page_title = "This is a simple demo";

function getPageContent() {
    return '<p>Hello World!</p>';
}

include('template_file.php');

I would do the following:

$string = <<< heredoc
plain text and now a function: %s
heredoc;
$string = sprintf($string, testfunction());

Not sure if you'd consider this to be more elegant ...

Try this (either as a global variable, or instantiated when you need it):

<?php
  class Fn {
    public function __call($name, $args) {
      if (function_exists($name)) {
        return call_user_func_array($name, $args);
      }
    }
  }

  $fn = new Fn();
?>

Now any function call goes through the $fn instance. So the existing function testfunction() can be called in a heredoc with {$fn->testfunction()}

Basically we are wrapping all functions into a class instance, and using PHP's __call magic method to map the class method to the actual function needing to be called.

Calling PHP functions within HEREDOC strings

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