Release 1.0.9

1.0.9

• Reject recursive trees. Thank you to Melody Ma for uncovering
  it. The API now raises an exception Recursion if you attempt to
  construct an AST that is not a DAG. (Note: you can of course still
  re-use nodes, as long as there are no loop in the DAG.)

• Add support for self-recursive records. This is a pre-cursor to full
  mutual recursion, but it is enough for TRLC.

  • The add_component method of Record can take the record sort
    itself.

  • A new expression Record_Null_Check can be used to check if a
    given term is equal to the null constructor. This can only be used
    on recursive records. Note that if you have a recursive record,
    then this is a pre-condition that you need to check on any access;
    otherwise you might get unexpected results (it is perfectly
    possible to access a record null constructor, you just get an
    uninterpreted function result). This checking has to happen inside
    the program driving PyVCG, it cannot happen inside PyVCG.

• Move to CVC 1.3.1.

• Add support for Python up to 3.14.