Fastmail Sieve Folders

sieve

if not string :is "${stop}" "Y"
{
### @xxx.com rules
if address :all :matches ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "*@xxx.com"
{
  if string :is ["deltachat"] "${1}" {
  fileinto "INBOX.DeltaChat";
  }
  else {
  fileinto :copy "INBOX.INBOX.personal";
  if string :is ["folder1", "folder2"] "${1}" {
    fileinto :copy "INBOX.INBOX.personal.${1}";
  }
  else {
    fileinto :copy "INBOX.INBOX.personal.catchall";
  }
  }
}

### @xx.yyy.com rules
if address :domain :is ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "xx.yyy.com" {
  fileinto "INBOX.INBOX.xx";
}

if address :all :matches ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "*@fastmail.com" {
  fileinto :copy "INBOX.INBOX.fastmail";

  if string :is "ggg" "${1}" {
    fileinto :copy "INBOX.INBOX.fastmail.ggg";
  }
  elsif string :is "fff" "${1}" {
    fileinto :copy "INBOX.INBOX.fastmail.fff";
  }
}
### School email rules
elsif address :all :is ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "[email protected]"
{
  fileinto :copy "INBOX.INBOX.school";
}

### Work email rules
elsif address :all :is ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "[email protected]"
{
  fileinto :copy "INBOX.INBOX.work";
}

### Labels receipt emails
if address :localpart :regex ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "^receipt.*"
{
  fileinto :copy "INBOX.receipt";
}
### Labels throwaway emails
elsif address :localpart :regex ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "^throwaway.*"
{
  fileinto :copy "INBOX.throwaway";
}
### Folder matching: "{1}/{2}" or "{1}-{2}" and files them
elsif address :localpart :regex ["To", "Cc", "Bcc", "Resent-To", "X-Delivered-To"] "^(([A-z]|[0-9])+)(\\/|-)(([A-z]|[0-9])+)" {
  fileinto :copy "INBOX.${1}";
  fileinto :copy "INBOX.${1}.${4}";
}

}

Line 57 for folder hierarchy