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// Copyright 2018 oooutlk@outlook.com. See the COPYRIGHT // file at the top-level directory of this distribution. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! # trees //! //! General purpose tree library. //! //! The current version provides two implementions of heap-allocated, child-sibling linked trees and one implementation of vec-backed tree. //! //! - The default implementation is [linked::fully](linked/fully/index.html), //! which stores previous/next sibling and parent/child pointers in one node, with size information tracked. //! //! - The alternative linked tree is [linked::singly](linked/singly/index.html), //! which stores only next sibling and last child pointers in one node, without size information tracked. //! The space cost is minimal, but with a few penalties on time cost or lack of function, e.g. linear time size_hint of iterators, and missing pop_back(). //! //! - The other alternative using vec as its underlying storage is [potted](potted/index.html). //! The memory allocations are minimal, and **trees can be written in Rust tuples**. //! Random access over child nodes is supported for tree/forest constructed in batch mode. //! //! More kinds of trees will be added in the future. //! //! This crate can be used with or without libstd. //! //! ## Quick start //! //! 1. Tree notation //! //! ```no_run //! use trees::tr; // tr stands for tree //! tr(0); // A single tree node with data 0. tr(0) has no children //! tr(0) /tr(1); // tr(0) has one child tr(1) //! tr(0) /tr(1)/tr(2); // tr(0) has children tr(1) and tr(2) //! //! // tr(0) has children tr(1) and tr(4), while tr(1) has children tr(2) and tr(3), and tr(4) has children tr(5) and tr(6). //! // The spaces and carriage returns are for pretty format and do not make sense. //! tr(0) //! /( tr(1) /tr(2)/tr(3) ) //! /( tr(4) /tr(5)/tr(6) ); //! ``` //! //! The potted version: //! ```no_run //! // the trees written in potted tree, same as described above //! use trees::potted::{Tree,TreeData,TupleTree}; //! Tree::from(( 0, )); //! Tree::from(( 0, 1 )); //! Tree::from(( 0, 1, 2 )); //! Tree::from(( 0, (1, 2, 3), (4, 5, 6))); //! ``` //! //! 2. Forest notation //! //! ```no_run //! use trees::{tr,fr}; // fr stands for forest //! //! fr::<i32>(); // An empty forest //! fr() - tr(1); // forest has one child tr(1) //! - tr(1); // forest has one child tr(1). The fr() can be omitted. The Neg operator for Tree converts the tree to a forest. //! - tr(1) - tr(2); // forest has child tr(1) and tr(2) //! tr(1) - tr(2); // forest has child tr(1) and tr(2). The leading neg can be omitted. //! //! // forest has children tr(1) and tr(4), while tr(1) has children tr(2) and tr(3), and tr(4) has children tr(5) and tr(6). //! -( tr(1) /tr(2)/tr(3) ) //! -( tr(4) /tr(5)/tr(6) ); //! //! // A tree tr(0) whose children equal to the forest descripted above. //! tr(0) /( //! -( tr(1) /( -tr(2)-tr(3) ) ) //! -( tr(4) /( -tr(5)-tr(6) ) ) //! ); //! ``` //! //! The potted version: //! ```no_run //! // the forests written in potted tree, same as described above //! use trees::potted::{Forest,TreeData,TupleForest,fr}; //! //! Forest::<i32>::new(); Forest::<i32>::from(( fr(), )); //! Forest::from(( fr(), 1 )); //! Forest::from(( fr(), 1, 2 )); //! Forest::from(( fr(), (1,2,3), (4,5,6) )); //! ``` //! //! 3. Tree traversal, using Node::iter() recursively //! //! ``` //! use trees::{tr,Node}; //! use std::fmt::Display; //! //! let tree = tr(0) //! /( tr(1) /tr(2)/tr(3) ) //! /( tr(4) /tr(5)/tr(6) ); //! //! fn tree_to_string<T:Display>( node: &Node<T> ) -> String { //! if node.is_leaf() { //! node.data.to_string() //! } else { //! format!( "{}( {})", node.data, //! node.iter().fold( String::new(), //! |s,c| s + &tree_to_string(c) + &" " )) //! } //! } //! //! assert_eq!( tree_to_string( &tree ), "0( 1( 2 3 ) 4( 5 6 ) )" ); //! ``` //! //! 4. String representation //! //! The Display trait has been implemented that is essentially the same as tree_to_tring() mentioned above. //! //! Children are seperated by spaces and grouped in the parentheses that follow their parent closely. //! //!``` //! use trees::{tr,fr}; //! //! let tree = tr(0) /( tr(1) /tr(2)/tr(3) ) /( tr(4) /tr(5)/tr(6) ); //! let str_repr = "0( 1( 2 3 ) 4( 5 6 ) )"; //! assert_eq!( tree.to_string(), str_repr ); //! //! assert_eq!( fr::<i32>().to_string(), "()" ); //! //! let forest = -( tr(1) /tr(2)/tr(3) ) -( tr(4) /tr(5)/tr(6) ); //! let str_repr = "( 1( 2 3 ) 4( 5 6 ) )"; //! assert_eq!( forest.to_string(), str_repr ); //!``` //! //! ## Slow start //! //! ### Concepts //! //! 1. Tree is composed of a root Node and an optional Forest as its children. A tree can NOT be empty. //! ``` //! use trees::{tr,Tree,Forest}; //! use std::pin::Pin; //! //! let mut tree: Tree<i32> = tr(0); //! //! let forest: Forest<i32> = -tr(1)-tr(2)-tr(3); //! tree.root_mut().append( forest ); //! assert_eq!( tree, tr(0) /tr(1) /tr(2) /tr(3) ); //! //! { let _forest: &Forest<i32> = tree.forest(); } //! { let _forest: Pin<&mut Forest<i32>> = tree.root_mut().forest_mut(); } //! { let _forest: Forest<i32> = tree.abandon(); } //! //! assert_eq!( tree, tr(0) ); //! ``` //! //! The potted version: //! ``` //! // potted::Forest cannot be borrowed from potted::Tree, and abandon is different. //! use trees::potted::{Tree,Forest,TreeData,TupleTree,TupleForest,fr}; //! //! let mut forest = Forest::from(( fr(), 1, 2, 3 )); //! let mut tree = forest.adopt( 0 ); //! assert_eq!( tree.to_string(), "0( 1 2 3 )" ); //! let ( root_data, forest ) = tree.abandon(); //! assert_eq!( root_data, 0 ); //! assert_eq!( forest.to_string(), "( 1 2 3 )" ); //! ``` //! //! 2. Forest is composed of Nodes as its children. A forest can be empty. //! ```no_run //! use trees::{tr,fr,Forest}; //! //! let mut forest: Forest<i32> = fr(); // an empty forest //! forest.push_back( tr(1) ); // forest has one tree, tr(1) //! forest.push_back( tr(2) ); // forest has two trees, tr(1) and tr(2) //! ``` //! //! The potted version: //! ```no_run //! use trees::potted::{Tree,Forest,TreeData,TupleForest}; //! let mut forest = Forest::<i32>::new(); // an empty forest //! forest.append_tr(( 1, 2, 3 )); // forest has three nodes //! ``` //! //! 3. Node is a borrowed tree, and Tree is an owned Node. All nodes in a tree can be referenced as &Node, but only the root node can be observed as Tree by the user. //! ```no_run //! use trees::{tr,Tree,Node}; //! use std::borrow::Borrow; //! //! let mut tree: Tree<i32> = tr(0) /tr(1)/tr(2)/tr(3); //! { //! let root: &Node<i32> = tree.borrow(); // you can also use tree.root() //! let first_child : &Node<i32> = tree.iter().next().unwrap(); //! let second_child: &Node<i32> = tree.iter().nth(1).unwrap(); //! let third_child : &Node<i32> = tree.iter().last().unwrap(); //! } //! let first_child: Tree<i32> = tree.root_mut().pop_front().unwrap(); //! ``` //! //! The potted version: //! ```no_run //! use trees::potted::{Tree,Node,TreeData,TupleTree}; //! let mut tree = Tree::from(( 0, 1, 2, 3 )); //! { //! let root: &Node<i32> = tree.root(); //! let first_child : &Node<i32> = tree.root().iter().next().unwrap(); //! let second_child: &Node<i32> = tree.root().nth_child(1).unwrap(); // nth_child() is in constant time. //! let third_child : &Node<i32> = tree.root().iter().last().unwrap(); //! } //! ``` //! //! ### Iterators //! //! The children nodes of a node, or a forest, is conceptually a forward list. //! //! 1. Using iter() to iterate over referenced child Nodes, you can: //! //! - read the data associated with each node. //! //! - use iter() to iterate over children's children, etc. //! //! 2. Using iter_mut() to iterate over referenced child Nodes, you can: //! //! - read/write the data associated with each node, or prepend(), append, abandon(), push_front(), pop_front(), push_back(), pop_back() child node(s) in constant time. //! //! Note that linked::singly does not have pop_back(), and potted tree/forest's methods are different in names and/or functionalities. //! //! - use iter_mut() to iterate over children's children, etc. //! //! 3. Using onto_iter() to iterate over Subnodes, you can: //! //! - insert_before, insert_after(), depart() node(s) at any position. //! //! - do whatever iter() or iter_mut() can do. //! //! Note that it is not implemented for potted version. //! //! 4. Using Forest::<T>::into_iter() to iterate over Trees, you can: //! //! - Do whatever you want to. //! //! Note that it is not implemented for potted version. //! //! ### Traversal in depth-first manner //! //! Using TreeWalk/ForestWalk to traverse on Tree/Forest, you can: //! //! 1. read the data associated with each descendant node in depth first manner, preorder or postorder at will. //! //! 2. visit Nodes irregularly, unlike the iterators mentioned above that are usually called intensively. //! //! Note that it is not implemented yet for potted version. //! //! ### Resource management //! //! 1. Tree/Forest will recursively destruct all the nodes owned by them when reaching the end of their lifetimes. //! //! 2. Clone for Tree and Forest makes deep copy which clones all its decendant nodes. To do copy for just one node, simplely let cloned = trees::tr( node.data.clone() );. //! //! 3. linked::fully::Node will track count of children nodes, and count of all descendant nodes and itself, while linked::singly::node does not track any size information. //! //! ### Traversal in breadth-first manner //! //! 1. Node provides (mutably) borrowed iterator fn bfs_iter( &self )/fn bfs_iter_mut( &mut self ). //! //! 2. Tree/Forest provides owned iterator fn bfs_into_iter( self ). //! //! 3. All version of Tree/Forest/Node support Into BFS streams, while potted version supports From BFS streams also. //! //! ### Panics //! //! One cause of panics is tree data's Clone: //! * Node::<T>::to_owned() //! * Tree::<T>::clone() //! * Forest::<T>::clone() //! * all of the operator overloading functions the operands of which contain at least one referenced type. //! //! A few assertions in potted version can also cause panics. //! //! ### Safety //! //! Collections of pointer-based tree implementation require many unsafes to do raw pointer dereferences. //! Currently this crate contains **200+ unsafe** blocks in its source code. //! This crate relies on lifetime bounds and borrow check to keep memory-safety, in compile time. //! The following are some simple demonstrations. //! //! ```compile_fail //! use trees::tr; //! //! let root; // node reference can not live longer than tree //! { //! let tree = tr(0); //! root = tree.root(); //! } //! root.push_back( tr(1) ); //! ``` //! //! ```compile_fail //! use trees::tr; //! //! let root; // mutable node reference can not longer than tree //! { //! let mut tree = tr(0); //! root = tree.root_mut(); //! } //! root.pop_front(); //! ``` //! //! ```compile_fail //! use trees::tr; //! //! let mut tree = tr(0) /tr(1); //! let child = tree.iter().next(); //! tree.abandon(); // can not drop sub trees being borrowed //! let _ = child.first(); //! ``` //! //! ```compile_fail //! use trees::{Node,tr}; //! //! let mut tree = tr(0) /tr(1) /tr(2); //! let child1 = tree.iter_mut().next().unwrap(); //! let child2 = tree.iter_mut().next().unwrap(); // can not have two mutable references on the same node //! child2.push_back( tr(3) ); //! child1.push_back( tr(4) ); //! ``` #![cfg_attr( feature = "no_std", no_std )] #![cfg_attr( feature = "no_std", feature( alloc ))] extern crate indexed; mod rust { #[cfg(not(feature="no_std"))] pub(crate) use std::borrow::{Borrow,ToOwned}; #[cfg(not(feature="no_std"))] pub(crate) use std::boxed::Box; #[cfg(not(feature="no_std"))] pub(crate) use std::collections::VecDeque; #[cfg(not(feature="no_std"))] pub(crate) use std::cmp::Ordering::{self,*}; #[cfg(not(feature="no_std"))] pub(crate) use std::fmt::{self,Debug,Display,Formatter}; #[cfg(not(feature="no_std"))] pub(crate) use std::hash::{Hasher,Hash}; #[cfg(not(feature="no_std"))] pub(crate) use std::iter::{Iterator,FromIterator,IntoIterator,FusedIterator}; #[cfg(not(feature="no_std"))] pub(crate) use std::marker::{PhantomData,Unpin}; #[cfg(not(feature="no_std"))] pub(crate) use std::mem::{self,forget,transmute}; #[cfg(not(feature="no_std"))] pub(crate) use std::ops::{Add,AddAssign,Deref,Div,Neg,Sub,SubAssign}; #[cfg(not(feature="no_std"))] pub(crate) use std::pin::Pin; #[cfg(not(feature="no_std"))] pub(crate) use std::ptr::{self,NonNull,null,null_mut}; #[cfg(not(feature="no_std"))] pub(crate) use std::vec::Vec; #[cfg(feature="no_std")] extern crate core; #[cfg(feature="no_std")] extern crate alloc; #[cfg(feature="no_std")] pub(crate) use self::alloc::borrow::{Borrow,ToOwned}; #[cfg(feature="no_std")] pub(crate) use self::alloc::boxed::Box; #[cfg(feature="no_std")] pub(crate) use self::alloc::string::String; #[cfg(feature="no_std")] #[cfg(test)] pub(crate) use self::alloc::string::ToString; #[cfg(feature="no_std")] pub(crate) use self::alloc::collections::VecDeque; #[cfg(feature="no_std")] #[cfg(test)] pub(crate) use self::alloc::format; #[cfg(feature="no_std")] pub(crate) use self::alloc::vec::Vec; #[cfg(feature="no_std")] pub(crate) use core::cmp::Ordering::{self,*}; #[cfg(feature="no_std")] pub(crate) use core::fmt::{self,Debug,Display,Formatter}; #[cfg(feature="no_std")] pub(crate) use core::hash::{Hasher,Hash}; #[cfg(feature="no_std")] pub(crate) use core::iter::{Iterator,FromIterator,IntoIterator,FusedIterator}; #[cfg(feature="no_std")] pub(crate) use core::marker::{PhantomData,Unpin}; #[cfg(feature="no_std")] pub(crate) use core::mem::{self,forget,transmute}; #[cfg(feature="no_std")] pub(crate) use core::ops::{Add,AddAssign,Deref,Div,Neg,Sub,SubAssign}; #[cfg(feature="no_std")] pub(crate) use core::pin::Pin; #[cfg(feature="no_std")] pub(crate) use core::ptr::{self,NonNull,null,null_mut}; } pub mod linked; pub use crate::linked::{tr,fr,Tree,Forest,Node,Iter,IterMut,Subnode,OntoIter,Visit,TreeWalk,ForestWalk}; pub mod potted; pub mod bfs; pub mod size; pub use size::Size;