bal
<<<
= /Checking/
  check account =~ /Foo/

2010-06-24 Sample
  Expenses:Food    $100
  Assets:Checking

check account("Assets:Checking").all(account =~ /Expense/)
>>>
               $-100  Assets:Checking
                $100  Expenses:Food
--------------------
                   0
>>>2
Warning: Transaction check failed: (account =~ /Foo/)
Warning: Check failed: account("Assets:Checking").all(account =~ /Expense/)