tiergraph 0.8.0

Added

• Added relation-instance references as targets of set_attribute,
  remove_attribute and remove_relation, so polyadic instances without
  durable ids can be edited and removed.
• Added declared work budgets for pattern views and binding, predicates,
  span-pair joins, lattice matching, folds and path plans. Exhaustion raises
  BudgetExhausted; outermost budgeted span scans can report cut-at-budget.
• Added opt-in CLI --max-steps and match-request max_steps work guards.
• Added work budgets to output-plan preparation, masses, conditioning and item
  marginals.
• Added work budgets to grammar recognition, derivation counts, best
  derivations and target generation.
• Added deterministic selector-scan and set-traversal charging to every
  budgeted selection; an ambient meter activates it around a nested
  SequenceSelector.
• Added opt-in Graph.share_values() to share equal item attributes and
  structural item references; the retained-memory saving holds once the caller
  drops the original graph.

Changed

• Graph.canonical_items() now returns durable items as the graph's own
  references, with unchanged values.
• Reduced compiled-pattern memory by packing NFA edges without changing matching results or work accounting.
• CompiledPattern.epsilon and CompiledPattern.atom_edges now hold packed integers.
• Avoided graph cycle walks for acyclic bipartite relations whose endpoint types
  are disjoint.
• Reduced graph construction overhead for empty and singleton attributes and
  valid structural references without relaxing their validation.
• Made integer-shaped decimal attribute construction avoid general Decimal
  re-parsing and reused the compiled whitespace normalizer.
• Made exact Decimal folds reuse sufficient context precision instead of
  recomputing a precision bound for every multiplication.
• Made ranked PATH folds concatenate already-singleton witness values directly
  instead of running general Cartesian deduplication and sorting.
• Lowered charged steps for large pattern alternations with bounded lookahead,
  without a wall-time gain, while preserving every pattern and lattice result.
  At a step-budget boundary, an outermost span call that previously refused may
  now return a nonempty cut-at-budget prefix; the reverse change cannot occur.
• Refused empty and non-string durable relation references and relation-instance
  durable ids at construction.
• Allowed layer flattening onto anonymous polyadic relation instances.
• Made pattern and embedded-predicate text parsing, and pattern compilation,
  independent of Python call stack depth and allowed 256 nested text groups.
  Pattern ASTs remain limited to 256 levels, and pattern and predicate NFAs to
  1,000,000 states.
• Stopped spans(limit=) once its extent is settled and made count avoid
  retaining span witnesses.