Question

There are a large numbers of PHP variables I use in my template files and some of them need to be accessible for editors who can only use HTML. What I want to do exactly is have them identify the variable doing something like [ITEM_NAME_1] when typing/editing content, and PHP finds them because they are wrapped in brackets, and replaces them with the appropriate PHP variable (in that case, $ITEM_NAME_1)

The content of each page is in a variable “$page_content”, so right now the only way I know how to accomplish is to manually write lines to replace what I need.

$page_content = str_replace("[ITEM_NAME_1]", "$ITEM_NAME_1", "$page_content"); 
print $page_content

The issue is there are hundreds of these “ITEM_NAME_X” variables and I don’t want to have to create a massive repeat of “str_replace” lines manually for each ITEM_NAME_X.

What I want to accomplish is have PHP find anything inside $page_content that is wrapped in brackets [], take the name from inside the bracket and replace all of it with the variable of that bracketted name. So if it finds [ITEM_5], it replaces it with $ITEM_5. Is this at all possible? Let me know, thanks.

Answer 1

Give preg_replace with the /e modifier a whirl. Combine that with variable variable name syntax to get the effect you want.

$page_content = preg_replace('/\[(.*?)\]/e', '$$1', $page_content);

This uses a regex to match strings between square brackets. The strings are captured and are accessed with $1 in the replacement string. The second $ looks up the variable named with whatever’s in $1.

If you want to do something more complicated with the replacement, you can invoke your own function from the replacement string. For example:

function substitute_tag($tag_name)
{
    $replacement_values = array('foo' => 'bar', 'baz' => '42', ...);
    return $replacement_values[$tag_name];
}

$page_content = preg_replace('/\[(.*?)\]/e', 'substitute_tag("$1")', $page_content);