Rust-Petgraph WASM项目，试图使用具有Graph属性的struct，但需要2个参数

Question

我是Rust的新手，所以这可能是一个非常新手的问题。

我正在尝试用rust->wasm创建一个网络应用程序。尝试遵循教程https://rustwasm.github.io/docs/book/introduction.html并尝试使用板条箱包装"petgraph"我想出了以下

use petgraph::graph::Graph;
#[wasm_bindgen]
pub struct TreeStructure {
directed_graph: Graph
}
#[wasm_bindgen]
impl TreeStructure {
pub fn new() -> TreeStructure {
TreeStructure {
directed_graph: Graph::<&str, &str>::new()
}
}
pub fn addNode(&mut self, newNode: &str) {
let findIndex = self.findNode(newNode);
if findIndex < 0 {
self.directed_graph.add_node(newNode);
} else {
alert("cant add, this {} already exist in the nodes", newNode);
}
}
pub fn removeNode(&mut self, toRemoveNode: &str) {
let findIndex = self.findNode(toRemoveNode);
if findIndex > -1 {
self.directed_graph.remove_node(toRemoveNode);
} else {
alert("cant remove, cannot find {} in the nodes", toRemoveNode);
}
}
pub fn addEdge(&mut self, fromNode: &str, toNode: &str) {
let fromIndex = self.findNode(fromNode);
let toIndex = self.findNode(toNode);
if fromIndex > -1 && toIndex > -1 {
let alreadyEdged = self.directed_graph.contains_edge(fromIndex, toIndex);
if !alreadyEdged {
self.directed_graph.add_edge(fromIndex, toIndex, "");
} else {
alert("edge already exist from {} to {}", fromNode, toNode);
}
}
}
pub fn getNeighbors(&self, checkNode: &str) -> Array {
let checkIndex = self.findNode(checkNode);
if checkIndex < 0 {
return vec![].into_inter().collect();
}
self.directed_graph.neighbors_directed(checkIndex).collect();
}
}
impl TreeStructure {
pub fn findNode(&self, nodeToFind: &str) -> i32 {
let findIndex = self.directed_graph.node_indices().collect::<Vec<_>>().iter().position(|&r| r == nodeToFind);
match findIndex {
Some(x) => x,
None => -1
}
}
}

但这给了我编译错误

error[E0107]: wrong number of type arguments: expected at least 2, found 0
--> src/lib.rs:25:25
|
25 |         directed_graph: Graph
|                         ^^^^^ expected at least 2 type arguments

阅读https://docs.rs/petgraph/0.5.0/petgraph/graph/struct.Graph.html然后我尝试了

use petgraph::graph::Node;
use petgraph::graph::Edge;
pub struct TreeStructure<N: Node, E: Edge> {
directed_graph: Graph<N, E>
}

但后来它说wasm-bindgen不支持这种语法？我在这里该怎么办？

Answer 1

假设new函数将Graph::<&str, &str>放在directed_graph中，这也是您应该在声明中使用的：

pub struct TreeStructure {
directed_graph: Graph<&str, &str>,
}

但是，这需要您指定生存期。我对wasm还不够熟悉，不能说哪一个是最好的(另外，这取决于你在图中到底放了什么(，但你可能需要使用'static生存期：

pub struct TreeStructure {
directed_graph: Graph<&'static str, & 'static str>,
}

这也将要求您为方法参数提供CCD_ 5生存期。或者你需要转移到拥有的字符串：

pub struct TreeStructure {
directed_graph: Graph<String, String>,
}

再次对方法进行适当的更改。