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Question

Calling PHP functions within HEREDOC strings

Answer 1

+2 A:

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 ...

boxxar 2008-09-19 18:59:53

Answer 2

+2 A:

You are pretty much describing what happens in a templating engine. You obviously know php pretty well. Have you considered taking a look at an actual templating engine?

Internet Friend 2008-09-19 19:02:25

Answer 3

+9 A:

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 WSYIWYG
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 we have the 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' );

Peter Bailey 2008-09-19 19:10:54

Answer 4

+1 A:

I'd take a look at Smarty as a template engine - I haven't tried any other ones myself, but it has done me well.

If you wanted to stick with your current approach sans templates, what's so bad about output buffering? It'll give you much more flexibility than having to declare variables which are the the sting names of the functions you want to call.

nickf 2008-09-19 23:42:49

Answer 5

+1 A:

I'm a bit late, but I randomly came across it. For any future readers, here's what I would probably do:

I would just use an output buffer. So basically, you start the buffering using ob_start(), then include your "template file" with any functions, variables, etc. inside of it, get the contents of the buffer and write them to a string, and then close the buffer. Then you've used any variables you need, you can run any function, and you still have the HTML syntaxt highlighting available in your IDE.

Here's what I mean:

Template File:

<?php echo "plain text and now a function: " . testfunction(); ?>

Script:

<?php
ob_start();
include "template_file.php";
$output_string = ob_get_contents();
ob_end_clean();
echo $output_string;
?>

So the script includes the template_file.php into its buffer, running any functions/methods and assigning any variables along the way. Then you simply record the buffer's contents into a variable and do what you want with it.

That way if you don't want to echo it onto the page right at that second, you don't have to. You can loop and keep adding to the string before outputting it.

I think that's the best way to go if you don't want to use a templating engine.

BraedenP 2009-09-06 20:49:04

Answer 6

+1 A:

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.

Isofarro 2009-12-22 18:11:55

Answer 7

A:

Guys should note that it also works with double-quoted strings.

http://www.php.net/manual/en/language.types.string.php

Interesting tip anyway.

SomeOne 2010-05-10 11:20:13

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Calling PHP functions within HEREDOC strings

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