babylon.engine.event_evaluator

Event Template evaluation engine.

Provides pure functions to evaluate EventTemplates against WorldState graphs. This is NOT a System - it’s a utility module used by Systems or the engine.

Sprint: Event Template System

Functions

aggregate_and_compare(values, aggregation, ...)	Aggregate values and compare to threshold.
calculate_graph_metric(graph, metric)	Calculate a graph-level aggregate metric.
compare(value, operator, threshold)	Apply comparison operator.
evaluate_edge_condition(condition, graph)	Evaluate an EdgeCondition against edges.
evaluate_graph_condition(condition, graph)	Evaluate a GraphCondition against graph-level metrics.
evaluate_node_condition(condition, graph)	Evaluate a NodeCondition against matching nodes.
evaluate_preconditions(preconditions, graph)	Evaluate a PreconditionSet against the graph.
evaluate_template(template, graph, current_tick)	Evaluate an EventTemplate against the current graph state.
filter_nodes(graph, node_filter)	Filter nodes based on NodeFilter criteria.
get_matching_nodes_for_resolution(template, ...)	Get nodes that match the template's node conditions.
get_nested_value(data, path)	Get a value from nested dict using dot notation.

babylon.engine.event_evaluator.evaluate_template(template, graph, current_tick)

Evaluate an EventTemplate against the current graph state.

Parameters:

• template (EventTemplate) – The EventTemplate to evaluate.

• graph (GraphProtocol) – Graph representing WorldState.

• current_tick (int) – Current simulation tick.

Return type:

Resolution | None

Returns:

The matching Resolution if preconditions met and a resolution matches, None otherwise.

babylon.engine.event_evaluator.evaluate_preconditions(preconditions, graph)

Evaluate a PreconditionSet against the graph.

Parameters:

• preconditions (PreconditionSet) – Set of conditions to evaluate.

• graph (GraphProtocol) – Graph to evaluate against.

Return type:

bool

Returns:

True if preconditions are satisfied, False otherwise.

babylon.engine.event_evaluator.evaluate_node_condition(condition, graph)

Evaluate a NodeCondition against matching nodes.

Parameters:

• condition (NodeCondition) – The node condition to evaluate.

• graph (GraphProtocol) – Graph to evaluate against.

Return type:

bool

Returns:

True if condition is satisfied, False otherwise.

babylon.engine.event_evaluator.evaluate_edge_condition(condition, graph)

Evaluate an EdgeCondition against edges.

Parameters:

• condition (EdgeCondition) – The edge condition to evaluate.

• graph (GraphProtocol) – Graph to evaluate against.

Return type:

bool

Returns:

True if condition is satisfied, False otherwise.

babylon.engine.event_evaluator.evaluate_graph_condition(condition, graph)

Evaluate a GraphCondition against graph-level metrics.

Parameters:

• condition (GraphCondition) – The graph condition to evaluate.

• graph (GraphProtocol) – Graph to evaluate against.

Return type:

bool

Returns:

True if condition is satisfied, False otherwise.

babylon.engine.event_evaluator.calculate_graph_metric(graph, metric)

Calculate a graph-level aggregate metric.

Parameters:

• graph (GraphProtocol) – Graph to analyze.

• metric (str) – Name of the metric to calculate.

Return type:

float

Returns:

The calculated metric value.

babylon.engine.event_evaluator.filter_nodes(graph, node_filter)

Filter nodes based on NodeFilter criteria.

Parameters:

• graph (GraphProtocol) – Graph containing nodes.

• node_filter (NodeFilter | None) – Filter criteria, or None for all nodes.

Return type:

list[str]

Returns:

List of node IDs matching the filter.

babylon.engine.event_evaluator.get_nested_value(data, path)

Get a value from nested dict using dot notation.

Follows the same pattern as TriggerCondition._get_nested_value.

Parameters:

• data (dict[str, Any]) – Dictionary to search.

• path (str) – Dot-notation path (e.g., ideology.agitation).

Return type:

float | None

Returns:

The value as float, or None if not found.

babylon.engine.event_evaluator.compare(value, operator, threshold)

Apply comparison operator.

Parameters:

• value (float) – Value to compare.

• operator (str) – Comparison operator.

• threshold (float) – Threshold to compare against.

Return type:

bool

Returns:

True if comparison succeeds, False otherwise.

babylon.engine.event_evaluator.aggregate_and_compare(values, aggregation, operator, threshold)

Aggregate values and compare to threshold.

Parameters:

• values (list[float]) – List of values to aggregate.

• aggregation (str) – Aggregation method.

• operator (str) – Comparison operator.

• threshold (float) – Threshold to compare against.

Return type:

bool

Returns:

True if aggregated comparison succeeds, False otherwise.

babylon.engine.event_evaluator.get_matching_nodes_for_resolution(template, graph)

Get nodes that match the template’s node conditions.

Used for ${node_id} substitution in resolution effects.

Parameters:

• template (EventTemplate) – The EventTemplate being resolved.

• graph (GraphProtocol) – Graph to search.

Return type:

list[str]

Returns:

List of node IDs that satisfy the node conditions.