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//! Graphity offers tools to model signal flow within directed graphs. //! //! There are two main parts playing a role here. First are nodes implemented by //! the user. These nodes can have arbitrary number of inputs and outputs, and //! an optional method performing operations over provided data. The second part //! is then a signal graph structure generated by this library. It allows the //! user to register previosly defined nodes, wire them up and let signal flow //! between them the user to register previosly defined nodes, wire them up and //! let signal flow between them. //! //! All the core concepts are illustrated by the following example. Read through //! the documentation of individual structs and traits to learn more. //! //! # Example //! //! This example will work with a signal graph containing 3 types of nodes: //! //! * `Generator` – pushing given value throught its output. //! * `Sum` – accepting two inputs and returning the sum of them. //! * `Echo` – accepting one input and printing it on the standard output as a //! side-effect. //! //! They will be wired up as following: //! //! ```text //! [Echo] //! Λ \ __ //! | \ / | | //! | [Sum] | | //! | / \__| V //! / //! [Generator(1)] //! ``` //! //! Generator sends value `1` to the first input of `Sum`. `Sum` sends the //! calculated result to its own second input, forming a loop. It will also send //! a copy of the result to `Echo`, so we can observe the current value. //! //! ## Defining nodes //! //! First, let's define all the modules. We'll start with `Sum` since it covers //! most of the important parts: //! //! ``` //! # use graphity::Node; //! #[derive(Default)] //! pub struct Sum { //! input1: i32, //! input2: i32, //! output: i32, //! } //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub enum SumConsumer { //! In1, //! In2, //! } //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub struct SumProducer; //! //! impl Node<i32> for Sum { //! type Consumer = SumConsumer; //! type Producer = SumProducer; //! //! fn write(&mut self, consumer: Self::Consumer, input: i32) { //! match consumer { //! Self::Consumer::In1 => self.input1 = input, //! Self::Consumer::In2 => self.input2 = input, //! } //! } //! //! fn read(&self, _producer: Self::Producer) -> i32 { //! self.output //! } //! //! fn tick(&mut self) { //! self.output = self.input1 + self.input2; //! } //! } //! ``` //! //! There is lot to discuss here, let's split it into parts. //! //! The first part simply defines the structure of the node. In this case, it //! has one field per each input/output to work with: //! //! ``` //! #[derive(Default)] //! pub struct Sum { //! input1: i32, //! input2: i32, //! output: i32, //! } //! ``` //! //! Next up, there is the definition of node's consumers. A consumer is simply //! an input pin of the node to which we can attach an edge. In this case it is //! an enum that can be one of two invariants, one for each input: //! //! ``` //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub enum SumConsumer { //! In1, //! In2, //! } //! ``` //! //! Similarly, node's producer is an output pin. In the case of this node, there //! is only one possible output, so we define a primitive struct as the type: //! //! ``` //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub struct SumProducer; //! ``` //! //! Each node provided by the user must implement the [Node //! trait](trait.Node.html). You can see that this is where we link previously //! defined consumers and producers. Note that the node is implemented for type //! `i32`. That is the payload type that will be used for data flowing between //! nodes. All consumers and producers within a graph must work with this type: //! //! ```ignore //! impl Node<i32> for Sum { //! type Consumer = SumConsumer; //! type Producer = SumProducer; //! // ... //! } //! ``` //! //! The `write` method will be used to provide data to the node. It passes the //! assigned `Consumer` to specify to which consumer is the data meant for. In //! this case, our `Sum` node has two inputs, one for each number to be summed: //! //! ```ignore //! fn write(&mut self, consumer: Self::Consumer, input: i32) { //! match consumer { //! Self::Consumer::In1 => self.input1 = input, //! Self::Consumer::In2 => self.input2 = input, //! } //! } //! ``` //! //! Its counterpart is the `read` method which will be called from the outside //! to read data produced by the node. Since our node has only one producer //! available, we can safely ignore the given `producer` value: //! //! ```ignore //! fn read(&self, _producer: Self::Producer) -> i32 { //! self.output //! } //! ``` //! //! Finally, we need to define the `tick` method which will process all the data //! set on the input and save the result on the output: //! //! ```ignore //! fn tick(&mut self) { //! self.output = self.input1 + self.input2; //! } //! ``` //! //! The remaining two nodes for completeness: //! //! ``` //! # use graphity::Node; //! pub struct Generator(i32); //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub enum GeneratorConsumer {} //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub struct GeneratorProducer; //! //! impl Node<i32> for Generator { //! type Consumer = GeneratorConsumer; //! type Producer = GeneratorProducer; //! //! fn read(&self, _producer: Self::Producer) -> i32 { //! self.0 //! } //! } //! //! #[derive(Default)] //! pub struct Echo { //! input: i32, //! } //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub struct EchoConsumer; //! //! #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)] //! pub enum EchoProducer {} //! //! impl Node<i32> for Echo { //! type Consumer = EchoConsumer; //! type Producer = EchoProducer; //! //! fn write(&mut self, _consumer: Self::Consumer, input: i32) { //! self.input = input; //! } //! //! fn tick(&mut self) { //! println!("Echo: {}", self.input); //! } //! } //! ``` //! //! ## Defining the graph //! //! The nodes do not bring much value on their own. The goal of this library is //! to make it easy to model signal flow between these nodes within a graph. //! //! To build such a graph, all you need to do is to call `graphity`, defining //! the name of the generated structure, the type of the payload passed between //! nodes and list of the previously defined nodes: //! //! ``` //! # use graphity_nodes::*; //! # #[macro_use] //! # extern crate graphity; //! # fn main() { //! graphity!( //! Graph<i32>; //! Generator = {Generator, GeneratorConsumer, GeneratorProducer}, //! Echo = {Echo, EchoConsumer, EchoProducer}, //! ); //! # } //! ``` //! //! Note that the macro is called within its own module to prevent conflicts //! with the rest of you code. //! //! ## Wiring it all up //! //! Finally, let's instantiate such a graph, add nodes, connect them a and let //! the signal flow. //! //! First, let's create an instance of the previously generated graph: //! //! ```ignore //! let mut graph = Graph::new(); //! ``` //! //! Then add nodes to it. The returned value is actually an index of the stored //! node and can be later used to access consumers and producers or remove the //! node: //! //! ```ignore //! let generator = graph.add_node(Generator(1)); //! let sum = graph.add_node(Sum::default()); //! let echo = graph.add_node(Echo::default()); //! ``` //! //! As the next step, we can create edges between producers and consumers of //! available nodes to form the topology described above: //! //! ```ignore //! graph.add_edge( //! generator.producer(GeneratorProducer), //! sum.consumer(SumConsumer::In1), //! ); //! graph.add_edge( //! sum.producer(SumProducer), //! sum.consumer(SumConsumer::In2), //! ); //! graph.add_edge( //! sum.producer(SumProducer), //! echo.consumer(EchoConsumer), //! ); //! ``` //! //! Once all is wired up, we can trigger tick of the graph. When this happens, //! the graph is traversed, all individual nodes ticket and their output passed //! on to the input of their connected nodes. In this example, you can see that //! the `Echo` node keeps reporting increasing number due to the cycle feeding //! back the output of the `Sum` to its input. //! //! ```ignore //! graph.tick(); //! graph.tick(); //! graph.tick(); //! ``` //! //! ```text //! Echo: 1 //! Echo: 2 //! Echo: 3 //! ``` //! //! You can find the full executable version of this example under the [project //! sources](https://github.com/zlosynth/graphity/tree/main/examples). //! //! Learn more about individual types in this documentation. Reading about the //! generated [`SignalGraph`](signal/struct.SignalGraph.html) would be a good //! start. #![no_std] extern crate alloc; pub mod error; mod feedback; mod graph; mod graphity; mod internal; pub mod node; pub mod signal; mod sort; pub use error::Error; pub use node::{Node, NodeIndex, NodeWrapper};