implementing digraph generation

src/rsprocess/graph.rs

@@ -0,0 +1,39 @@
+#![allow(dead_code)]
+
+use petgraph::Graph;
+use std::collections::HashMap;
+use super::structure::{RSlabel, RSsystem};
+use super::support_structures::TransitionsIterator;
+
+pub fn digraph(
+    system: RSsystem
+) -> Result<Graph<RSsystem, RSlabel>, String> {
+    let mut graph: Graph<RSsystem, RSlabel> = Graph::new();
+    let node = graph.add_node(system.clone());
+
+    let mut association = HashMap::new();
+    association.insert(system.clone(), node);
+
+    let mut stack = vec![system];
+    let mut current;
+
+
+    while !stack.is_empty() {
+	// depth first
+	current = stack.pop().unwrap();
+	let current_node = *association.get(&current).unwrap();
+
+	// cycle through all next nodes
+	let tr = TransitionsIterator::from(&current)?;
+
+	for (label, next) in tr {
+	    // if not already visited
+	    let next_node = association.entry(next.clone()).or_insert_with(|| {
+		stack.push(next.clone());
+		graph.add_node(next)
+	    });
+	    graph.add_edge(current_node, *next_node, label);
+	}
+    }
+    Ok(graph)
+}