Added support for assert, check and expr directives

These can occur in many places:

  ; Within an automated transaction, the assert is evaluated every time
  ; a posting is matched, with the expression context set to the
  ; matching posting.
  = /Food/
    assert account("Expenses:Food").total >= $100

  2010-06-12 Sample
    Expenses:Food                $100
    Assets:Checking

  ; At file scope, the expression is evaluated with "global" scope.
  assert account("Expenses:Food").total == $100

  ; At the top of a transction, the assertion's scope is the
  ; transaction.  After a posting, the scope is that posting.  Note
  ; however that account totals are only adjusted after successful
  ; parsing of a transaction, which means that all the assertions below
  ; are true, even though it appears as though the middle posting should
  ; affect the total immediately (which is not the case).
  2010-06-12 Sample 2
    assert account("Expenses:Food").total == $100
    Expenses:Food                $50
    assert account("Expenses:Food").total == $100
    Assets:Checking
    assert account("Expenses:Food").total == $100

0 files changed, 0 insertions, 0 deletions