页眉和页脚在单独的.php中,当前页面突出显示

I didn't code for years and I probably forgot everything, but I'm trying to start again to develop my personal website. I would like to put the div header and the div footer in a .php file so I don't have to manually modify every single page in case of modifications. My idea was like:

header-footer.php

<?php function head()
       {echo '<ul>
                <li><a href="tutorial.html"' if($current == "tutorial") {echo 'class="menu_link_active"';} else {echo 'class="menu_link"';} '>Tutorials</a></li>
                <li><a href="contact.html"' if($current == "contact") {echo 'class="menu_link_active"';} else {echo 'class="menu_link"';} '>Contatti</a></li>
               </ul>';}

function foot()
  {echo '...html...';} ?>

The function head() should recognize the current page to highlight it. Then in the pages of my website I include the header-footer.php like this:

<head><?php include("php/header-footer.php"); ?><head>

Calling into the the two functions:

<body><?php $current = "projemi";
            head();?>
      ...html code...
      <?php foot(); ?></body>

My questions are: 1) the page displays this error: ----syntax error, unexpected 'if' (T_IF), expecting ',' or ';'---- and it referres to the head function. Where is the error? 2) Is it correct the process to obtain what I want or you would suggest something different?

Thanks you so much guys, and forgive me for my bad english!

You have to pass the value into the function to use

  <?php 
      function head($current){
         echo '<ul>
            <li><a href="tutorial.html"';
         if($current == "tutorial") {
                 echo 'class="menu_link_active"';
         }else {
                echo 'class="menu_link"';
         } 
         echo '>Tutorials</a></li><li><a href="contact.html"'; 
         if($current == "contact") {
              echo 'class="menu_link_active"';
          } else {
              echo 'class="menu_link"';
          } 
          echo '>Contatti</a></li></ul>';
        }
    ?>

Call your function like

  <?php
     $current = 'someVal';
     head($current);
  ?>

Well, you forgot to end your echo statement with a semicolon first off, hence the error.

echo '<ul>
                <li><a href="tutorial.html"'; if($current == "tutorial") {echo 'class="menu_link_active"';} else {echo 'class="menu_link"';} '>Tutorials</a></li>
                <li><a href="contact.html"'; if($current == "contact") {echo 'class="menu_link_active"';} else {echo 'class="menu_link"';} '>Contatti</a></li>
               </ul>';

Also, suggestion, I believe this would be more efficient (I'd recommend to just develop an MVC-like system, but that's a bit tad too complicated for what you want do to):

echo '<ul>
                <li><a href="tutorial.html"'.(($current === 'tutorial') ? 'class="menu_link_active"' : 'class="menu_link"').'>Tutorials</a></li>
                <li><a href="contact.html"'.(($current === 'contact') ? 'class="menu_link_active"' : 'class="menu_link"').'>Contatti</a></li>
               </ul>';