Fixes a bug that basically prevented the grammar from being read from STDIN.
The script seemed to allow reading from STDIN, since it explicitly sets $grammarFile to "php://stdin" if it's equal to "-". However, "php://stdin" fails the file_exists check that happens shortly after, which causes the script to terminate with exit code 4. This fixes that.
Fixes a bug that basically prevented the grammar from being read from STDIN.
The script seemed to allow reading from STDIN, since it explicitly sets
$grammarFileto"php://stdin"if it's equal to"-". However,"php://stdin"fails thefile_existscheck that happens shortly after, which causes the script to terminate with exit code 4. This fixes that.