Question

Let’s say I have this array:

$meta = array(
    'name' => 'John Doe',
    'age' => 16,
    'e-mail' => '[e-mail]'
);

How Do I allow users to customize the layout using those variables? (And be able to catch errors). Here’s my current idea:

extract($meta,EXTR_OVERWRITE);
$string = "Hi, I am $name. This is an $undefined_variable";

It isn’t able to catch undefined variables though.

Answer 1

How about this?

$string = "Hi, I am {{name}}. This is an {{undefined_variable}}";
foreach ($meta as $key => $value) {
    $string = str_replace('{{' . $key . '}}', $value, $string);
}

Or, if you could have {{name}}, etc, directly as keys in $meta, then:

$string = "Hi, I am {{name}}. This is an {{undefined_variable}}";
$string = str_replace(array_keys($meta), array_values($meta), $string);

Or, you could create and cache a $meta with {{...}} keys if you can’t place them in the original one:

$metaTokens = array();
foreach ($meta as $key => $value) {
    $metaTokens['{{' . $key . '}}'] = $value;
}

Then, if you want to simply hide the undefined variables, by now you should have all the defined ones filled in, so anything else inside {{..}} should be an undefined variable:

$string = preg_replace('/{{.+?}}/', '', $string);