Changelog

✅ Recent Major Completions

Handler-Based Security - Replaces dangerous arbitrary function execution with secure handler registration system
SCXML Event Compliance - Generates proper done.invoke.{id}, error.execution, and error.communication events per specification
Centralized Parameter Processing - Unified <param> evaluation with strict (InvokeAction) and lenient (SendAction) error handling modes
External Service Integration - Safe way to integrate SCXML state machines with external services and APIs
Complete Test Coverage - InvokeAction and InvokeHandler modules achieve 100% test coverage
Parameter Architecture Refactor - Consolidated parameter evaluation logic removes code duplication across actions

Shallow History - Records and restores immediate children of parent states that contain active descendants
Deep History - Records and restores all atomic descendant states within parent states
History Tracking - Complete Statifier.HistoryTracker module with efficient MapSet operations
History Validation - Comprehensive Statifier.Validator.HistoryStateValidator with W3C specification compliance
History Resolution - Full W3C SCXML compliant history state transition resolution during interpreter execution
StateChart Integration - History tracking integrated into StateChart lifecycle with recording before onexit actions
SCION Test Coverage - Major improvement in SCION history test compliance (5/8 tests now passing)

Space-Separated Parsing - Handles target="state1 state2 state3" syntax with proper whitespace splitting
API Enhancement - Statifier.Transition.targets field (list) replaces target field (string) for better readability
Validator Updates - All transition validators updated for list-based target validation with comprehensive testing
Parallel State Fixes - Critical parallel state exit logic improvements with proper W3C SCXML exit set computation
SCION Compatibility - history4b and history5 SCION tests now pass completely with multiple target support

Microstep/Macrostep Execution - Implements SCXML event processing model with microstep (single transition set execution) and macrostep (series of microsteps until stable)
Eventless Transitions - Transitions without event attributes (called NULL transitions in SCXML spec) that fire automatically upon state entry
Exit Set Computation - Implements W3C SCXML exit set calculation algorithm for determining which states to exit during transitions
LCCA Algorithm - Full Least Common Compound Ancestor computation for accurate transition conflict resolution and exit set calculation
Cycle Detection - Prevents infinite loops with configurable iteration limits (100 iterations default)
Parallel Region Preservation - Proper SCXML exit semantics for transitions within and across parallel regions
Optimal Transition Set - SCXML-compliant transition conflict resolution where child state transitions take priority over ancestors

Cross-Parallel Boundaries - Proper exit semantics when transitions leave parallel regions
Sibling State Management - Automatic exit of parallel siblings when transitions exit their shared parent
Self-Transitions - Transitions within parallel regions preserve unaffected parallel regions
Parallel Ancestor Detection - New functions for identifying parallel ancestors and region relationships
Enhanced Exit Logic - All parallel regions properly exited when transitioning to external states

Statifier.FeatureDetector - Analyzes SCXML documents to detect used features
Feature validation - Tests fail when they depend on unsupported features
False positive prevention - No more "passing" tests that silently ignore unsupported features
Capability tracking - Clear visibility into which SCXML features are supported

Parser support - <initial> elements with <transition> children
Interpreter logic - Proper initial state entry via initial elements
Comprehensive validation - Conflict detection, target validation, structure validation
Feature detection - Automatic detection of initial element usage

For current feature status and working capabilities, see the main README.