Module behavior_tree 

Behavior Tree system — full implementation with composites, decorators, actions, conditions, blackboard, and a fluent builder DSL.

Design

• Tick-based execution: tree.tick(&mut ctx) returns Status.
• Blackboard: shared key/value store passed through context.
• Nodes are boxed trait objects — fully dynamic, composable at runtime.
• Zero unsafe, no external dependencies beyond std.

Quick Start

use proof_engine::ai::behavior_tree::*;
let tree = BehaviorTreeBuilder::new()
    .sequence()
        .condition(|ctx| ctx.blackboard.get_float("health") > 0.0)
        .action(|ctx| { ctx.blackboard.set("attacking", true); Status::Success })
    .end()
    .build();

Structs

ActionNode

A leaf that performs an action and returns a status.

AiEntity

Generic AI entity for use in example behavior trees.

BehaviorTree

The top-level behavior tree — wraps a root node.

Blackboard

Shared data store accessible by all tree nodes.

BlackboardHas

Checks if a blackboard key has been set.

CheckFloat

CommonBehaviors

Factory for common pre-built behavior trees using AiEntity.

ConditionNode

A leaf that evaluates a closure against the context.

Cooldown

Prevents child from running until a cooldown expires.

Failer

Always returns Failure regardless of child result.

FireEvent

Fires a named event into the context and succeeds.

Guard

Guards child behind a blackboard condition. Re-evaluated every tick.

Inverter

Inverts the child’s result.

Parallel

RandomSelector

Shuffles children order each activation, then tries them in that order.

Repeater

Repeats child N times, or infinitely if N is None.

RetryUntilFail

Repeats until the child fails.

Selector

Executes children left-to-right. Succeeds on FIRST success. Fails if ALL fail. Memory selector: remembers the currently running child.

Sequence

Executes children left-to-right. Succeeds if ALL succeed. Fails on first failure. Remembers the currently running child (memory sequence).

SetBool

Sets a bool on the blackboard and succeeds.

SetFloat

Sets a float on the blackboard and succeeds.

SubTree

Delegates to a separately defined subtree by name. The subtree is looked up in a SubTreeRegistry stored on the blackboard via a string key. For simplicity, we inline the subtree node directly.

Succeeder

Always returns Success regardless of child result.

TickContext

Context passed to every tick call.

TimeLimit

Limits child execution to a maximum wall-clock duration (in seconds).

TreeRunner

Manages a behavior tree instance for one entity, tracking timing and events.

Wait

Waits for duration seconds, then succeeds.

WaitRandom

Waits for a random duration in [min, max] seconds.

Enums

FloatComparison

Checks a float comparison against a threshold.

ParallelPolicy

Ticks ALL children every frame. Success/failure policy configurable.

Status

The execution status returned by every tree node.

Traits

Node

A node in the behavior tree.