Currently the negation formatting is not explicitly specified in the standard.
It can be written either:
- with no spaces
if (!is_array($foo))
- with space after
if (! is_array($foo))
- with spaces around
if ( ! is_array($foo))
In the Scalar types chapter there is a code example which includes negation formatted without spaces around:
<?php
if (!is_int($foo)) {
return (int) $foo;
}
So it would be nice to have it explicitly stated in the coding standard. Maybe eventually also checked automatically (but PHP_CodeSniffer currently offers only SpaceAfterNotSniff).