vmware/differential-datalog v0.48.0

DDlog v0.48.0

on GitHub

New features

• Added change profiling support to the DDlog self-profiler. Unlike arrangement size
  profiling, which tracks the number of records in each arrangement, the change profile
  shows the amount of churn. For example adding one record and deleting one record will
  show up as two changes in the change profile, but will cancel out in the size profile.
  The self-profiler now support the profile change on/off commands (also available
  through the API), which enables change profiling for selected transactions.
  When change profiling is disabled, the recording stops, but the previously accumulated
  profile is preserved. By selectively enabling change profiling for a subset of transactions,
  the user can focus their analysis on specific parts of the program.

• Limited support for dynamic typing. We introduce a new type Any to the standard
  library, which can represent any DDlog value, along with two library functions
  to_any() and from_any() that convert values to and from this type. This
  feature can be used to, e.g., store a mix of values of different types in a
  set or map.

• Experimental features to support implementing parts of D3log runtime in DDlog.
  See #1065 for details.

Language and standard library changes

• The semantics of the group_by operator changed in a subtle way. A group
  now contain exactly one occurrence of each value. See #1070 for details.

• Removed ddlog_std::count(Group) and ddlog_std::group_count(Group) methods
  to avoid changing their behavior in a non-backwards-compatible way. Added
  count_distinct(Group) instead, which returns the count of distinct values in
  the group.

• Removed ddlog_std::group_sum(Group). Added
  function sum_of(g: Group<'K, 'V>, f: function('V): 'N): 'N instead.