Optional serde support (#37)

This PR makes serde an optional feature. 

I also added serialization derive traits to `BT` struct so you can now
serialize the whole behavior tree.

bonsai/Cargo.toml

@@ -12,16 +12,18 @@ name = "bonsai-bt"
 readme = "../README.md"
 repository = "https://github.com/sollimann/bonsai.git"
 rust-version = "1.80.0"
-version = "0.7.0"
+version = "0.8.0"
 
 [lib]
 name = "bonsai_bt"
 path = "src/lib.rs"
 
 [dependencies]
 petgraph = "0.6.2"
-serde = { version = "1.0.137", features = ["derive"] }
-serde_json = "1.0.81"
+serde = { version = "1.0.137", features = ["derive"] , optional = true }
+
+[dev-dependencies]
+serde_json = { version = "1.0.81" }
 
 [[test]]
 name = "tests"

bonsai/src/behavior.rs

@@ -1,8 +1,12 @@
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 /// Describes a behavior.
 ///
 /// This is used for more complex event logic.
 /// Can also be used for game AI.
-#[derive(Clone, serde::Deserialize, serde::Serialize, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Behavior<A> {
     /// Waits an amount of time before continuing
     ///
@@ -125,6 +129,7 @@ pub enum Behavior<A> {
 }
 
 #[cfg(test)]
+#[cfg(feature = "serde")]
 mod tests {
     use crate::Behavior::{self, Action, Sequence, Wait, WaitForever, WhenAny, While};
 

bonsai/src/bt.rs

@@ -1,10 +1,12 @@
 use std::fmt::Debug;
 
+use crate::visualizer::NodeType;
+use crate::{ActionArgs, Behavior, State, Status, UpdateEvent};
 use petgraph::dot::{Config, Dot};
 use petgraph::Graph;
 
-use crate::visualizer::NodeType;
-use crate::{ActionArgs, Behavior, State, Status, UpdateEvent};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 
 /// A "blackboard" is a simple key/value storage shared by all the nodes of the Tree.
 ///
@@ -15,6 +17,7 @@ use crate::{ActionArgs, Behavior, State, Status, UpdateEvent};
 ///
 /// An "entry" of the Blackboard is a key/value pair.
 #[derive(Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct BlackBoard<K>(K);
 
 impl<K> BlackBoard<K> {
@@ -26,6 +29,7 @@ impl<K> BlackBoard<K> {
 /// The BT struct contains a compiled (immutable) version
 /// of the behavior and a blackboard key/value storage
 #[derive(Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct BT<A, K> {
     /// constructed behavior tree
     pub state: State<A>,

bonsai/src/event.rs

@@ -1,9 +1,13 @@
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 /// Update arguments, such as delta time in seconds.
 /// To move the behavior tree forward in time it must be ticked on each iteration of the
 /// game/application loop.
 ///
 /// dt: states how much forward in time we should move the behavior tree
-#[derive(Copy, Clone, PartialEq, PartialOrd, Debug, serde::Deserialize, serde::Serialize)]
+#[derive(Copy, Clone, PartialEq, PartialOrd, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct UpdateArgs {
     /// Delta time in seconds.
     pub dt: f64,
@@ -17,7 +21,8 @@ impl UpdateArgs {
 }
 
 /// Models loop events.
-#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, serde::Deserialize, serde::Serialize)]
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Loop {
     /// Update the state of the application.
     Update(UpdateArgs),

bonsai/src/state.rs

@@ -1,13 +1,13 @@
-use std::fmt::Debug;
-
 use crate::event::UpdateEvent;
 use crate::sequence::{sequence, SequenceArgs};
 use crate::state::State::*;
 use crate::status::Status::*;
 use crate::when_all::when_all;
 use crate::{Behavior, Status};
+use std::fmt::Debug;
 
-// use serde_derive::{Deserialize, Serialize};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 
 /// The action is still running, and thus the action consumes
 /// all the remaining delta time for the tick
@@ -26,7 +26,8 @@ pub struct ActionArgs<'a, E: 'a, A: 'a> {
 }
 
 /// Keeps track of a behavior.
-#[derive(Clone, Debug, serde::Deserialize, serde::Serialize, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum State<A> {
     /// Executes an action.
     ActionState(A),

bonsai/src/status.rs

@@ -1,4 +1,5 @@
-// use serde_derive::{Deserialize, Serialize};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 
 /// The result of a behavior or action.
 ///
@@ -7,7 +8,8 @@
 /// * Success
 /// * Failure or
 /// * Running, if the action is asynchronous and it needs more time to complete
-#[derive(Copy, Clone, serde::Deserialize, serde::Serialize, PartialEq, Eq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Status {
     /// The behavior or action succeeded.
     Success,

examples/Cargo.toml

@@ -8,7 +8,7 @@ rust-version = "1.56.0"
 version = "0.1.0"
 
 [dependencies]
-bonsai-bt = { path = "../bonsai" }
+bonsai-bt = { path = "../bonsai" , features = ["serde"]}
 futures = "0.3.24"
 tokio = { version = "1.21.1", features = [
     "rt-multi-thread",

examples/src/graphviz/main.rs

@@ -1,14 +1,14 @@
-use std::collections::HashMap;
-
 use bonsai_bt::{
     Behavior::{Action, Sequence, Wait, WaitForever, WhenAny, While},
     BT,
 };
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
 
 type Damage = f64;
 type Distance = f64;
 
-#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, PartialEq)]
+#[derive(Deserialize, Serialize, Clone, Debug, PartialEq)]
 enum AttackDrone {
     /// Circles forever around target pos.
     Circling,

examples/src/simple_npc_ai/main.rs

@@ -1,7 +1,7 @@
 use bonsai_bt::Behavior::WhileAll;
 use bonsai_bt::{Behavior::Action, Event, Failure, Running, Status, Success, UpdateArgs, BT};
 
-#[derive(serde::Deserialize, serde::Serialize, Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum EnemyNPC {
     Run,
     Shoot,