pCG Bug List


Bugs and limitations of the initial public release of pCG.

  • Single and double quoted strings in concept referents are not considered equivalent in exact graph matching, e.g. [Cat: "foo"] is not the same as [Cat: 'foo']. The proposed ANSI CG standard implies that they are not equivalent anyway, so this is arguably not a bug.
  • A non-fatal Java VM JIT error sometimes occurs under Windows (tested under Win98) using JDK 1.2.2.
  • Error messages need to be made more descriptive and less generic in some cases, especially with respect to object operation invocation.
  • LF input is buggy, since Notio's example LF parser is being used and is documented as being buggy.
  • Marker sets are not currently implemented.
  • The conformity relation is not currently implemented.
  • Implication of the form ~[u ~[v]] is not currently implemented.
  • Only a special form of negation is available in process preconditions. See the included documentation.
  • pCG's attribute/operation and list indexing operators have precedence problems in the current grammar, requiring combinations of them to be parenthesised. See the included documentation.
  • If a pCG program does not end with a blank line, the interpreter may yield a tokenstream error message.