Syntax errors in filters

[mfields]

Could be wrong, but should the "$" be inside the curly braces or does it matter?

Line 536:
$actions = apply_filters("${taxonomy}_row_actions", $actions, $tag);

Line 564:
apply_filters("manage_${taxonomy}_custom_column", , $column_name, $tag->term_id);

​https://core.trac.wordpress.org/browser/trunk/wp-admin/includes/template.php

It looks weird, but it works. It's a way to define a variable variable.

$foo = 'bar';
$baz = "${foo}";
var_dump( $baz ); // string(3) "bar"
$baz = "{$foo}";
var_dump( $baz ); // string(3) "bar"

Based on a real quick test, it appears to be a negligible difference in performance.

nacin - Thanks for the info! I have never seen anything like this before so was prompted to ask.

It does look weird at first if you've never seen it. But it is syntactically correct.

It reduces errors too, take this for example:

"${bar}_test"
"{$bar}_test"
"$bar_test"
//Ok, All those look sane, now try:
"${bar_foo_result}_taz"
"{$bar_foo_result}_taz"
"$bar_foo_result_taz"

The braces just make it that much more clearer that the variable name is held within, and that the braces will not appear in the final string..