Setting a variable for a view template

Question

As you can see from the code below, my set function accepts two types of parameters: either strings or arrays. Now, ideally I would like to be using operator overloading to handle this, but since PHP doesn't offer anything like that I am stuck with code like this. Is there a better way to write this (or perhaps a better way to address the problem altogether)?

class View {
 // stores file passed to View
 private $template;
 // setter function for template variables
 public function set($var, $content) {
 if (is_array($var) && is_array($content)) {
 if (sizeof($var) == sizeof($content)) {
 foreach ($var as $vari) {
 foreach ($content as $contenti) {
 $this->template = str_replace("{" . "$vari" . "}", $contenti, $this->template);
 }
 }
 }
 }
 else {
 $this->template = str_replace("{" . "$var" . "}", $content, $this->template);
 }
 }
}

Answer 1

First, there is a simple way to flatten out those loops, but it is not what I would suggest. Here is the simple way:

if ((sizeof($var) == sizeof($content))) {
 $count = sizeof($var);
 for ($i =0; $i < $count; $i++) {
 $this->template = str_replace(
 '{' . $var[$i] . '}', $content[$i], $this->template);
 }
}

Note that you are currently silently doing nothing when the size of your arrays don't match. I think that is a bug.

My Suggestions

$var and $content are not very descriptive: I would suggest $match and $replacement.

str_replace can handle arrays as input. I would suggest filling your match with the '{' and '}' beforehand. The code then becomes:

public function set($match, $replacement)
{
 $this->template = str_replace($match, $replacement, $this->template);
}

I would place any sanity checks before the str_replace that you require. str_replace uses blank replacements when the matches array is larger than the replacements. If you want to avoid that use:

 if (is_array($match) && is_array($replacement) &&
 sizeof($match) > sizeof($replacement))
 {
 throw new InvalidArgumentException(
 __METHOD__ . ' Each match must have a replacement');
 }

This avoids arrow code which will make the code easier to test, reduce its complexity and make it easier to maintain.

• Moses: Interesting, I had no idea I could pass arrays directly into str_replace and it would handle the iteration for me behind the scenes! Additionally, I believe you forgot to include the third parameter in your str_replace function; shouldn't it read: $this->template = str_replace($match, $replacement, $this->template);

Answer 2

You could use preg_replace_callback to iterate through your array and replace any data.

public function set($data){ // data = array
 $callback = function ($matches) use ($data)
 {
 return ( isset($data[$matches[1]]) ) 
 ? $data[$matches[1]] 
 : $matches[0];
 };
 return preg_replace_callback(
 '/\{(.*?)\}/', 
 $callback, 
 $this->template);
}