get_functions_in_file.php

<?php

/**
 * Returns an array of function names in a file.
 *
 * @param (string) $file
 *   The path to the file.
 *
 * @param (bool) $sort
 *   If TRUE, sorts results by funciton name.
 */
function get_functions_in_file($file, $sort = FALSE) {
  $file = file($file);
  $functions = array();

  foreach ($file as $line) {
    $line = trim($line);
    if (substr($line, 0, 8) == 'function') {
      $functions[] = substr($line, 9, strpos($line, '(') - 9);
    }
  }

  if ($sort) {
    asort($functions);
    $functions = array_values($functions);
  }

  return $functions;
}

This fails in cases where we use access property types like public, protected, private and static etc.

Here is the fix to that

function get_functions_in_file($file, $sort = FALSE) {
    $file = file($file);
    $functions = array();
    foreach ($file as $line) {
        $line = trim($line);
        if (stripos($line, ' function ') !== false) {
            $function_name = str_ireplace([
                'public', 'private', 'protected',
                'static'
                    ], '', $line);

            if (!in_array($function_name, ['__construct', '__destruct'])) {
                $functions[] = trim(substr($function_name, 9, strpos($function_name, '(') - 9));
            }
        }
    }
    if ($sort) {
        asort($functions);
        $functions = array_values($functions);
    }
    return $functions;
}

a little fixe's :

function getFileFunctions (string $filePath, bool $sort = false) : array {
	$file      = file($filePath);
	$functions = [];

	foreach ( $file as $line ) {
		$line = trim($line);

		if ( stripos($line, 'function ') !== false ) {
			$function_name = trim(str_ireplace([
				'public',
				'private',
				'protected',
				'static'
			], '', $line));

			$function_name = trim(substr($function_name, 9, strpos($function_name, '(') - 9));

			if ( !in_array($function_name, ['__construct', '__destruct', '__get', '__set', '__isset', '__unset']) ) {
				$functions[] = $function_name;
			}
		}
	}

	if ( $sort ) {
		asort($functions);
		$functions = array_values($functions);
	}

	return $functions;
}