lollipop operator without prefix

src/main.rs

@@ -170,7 +170,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 						       )
 						   ]));
 
-    let res = rsprocess::perpetual::lollipops(sys);
+    let res = rsprocess::perpetual::lollipops(sys.clone());
 
     println!("res:");
     for (prefix, hoop) in res {
@@ -184,5 +184,16 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 	}
 	println!();
     }
+
+    let res = rsprocess::perpetual::lollipops_only_loop(sys);
+
+    println!("res:");
+    for hoop in res {
+	print!("hoop: ");
+	for l in hoop {
+	    print!("{}, ", WithTranslator::from_RSset(&translator, &l));
+	}
+	println!();
+    }
     Ok(())
 }

src/rsprocess/perpetual.rs

@@ -1,55 +1,87 @@
 #![allow(dead_code)]
 
 use std::rc::Rc;
-
 use super::classical::compute_all_owned;
 use super::translator::IdType;
 use super::structure::{RSsystem, RSprocess, RSset, RSreaction};
 
+// finds only the rules X = pre(Q, rec(X)), but not only x = pre(Q, rec(x))
+// to use in filter_map
+fn filter_delta<'a>(x: (&IdType, &'a RSprocess)) -> Option<&'a RSset> {
+    use super::structure::RSprocess::*;
+    let (id, rest) = x;
+    match rest {
+	EntitySet{ entities, next_process} => {
+	    match &**next_process {
+		RecursiveIdentifier{ identifier } if identifier == id => {
+		    Some(entities)
+		},
+		_ => None
+	    }
+	},
+	_ => None
+    }
+}
+
+// returns the prefix and the loop from a trace
 fn split<'a>(set: &'a RSset, trace: &'a [RSset]) -> Option<(&'a[RSset], &'a[RSset])> {
     let position = trace.iter().rposition(|x| x == set);
     position.map(|pos| trace.split_at(pos))
 }
 
-fn find_loop(rs: &Rc<Vec<RSreaction>>, e: RSset, q: &RSset) -> (Vec<RSset>, Vec<RSset>) {
-    let mut e = e;
+// finds the loops by simulating the system
+fn find_loop(rs: &Rc<Vec<RSreaction>>, entities: RSset, q: &RSset) -> (Vec<RSset>, Vec<RSset>) {
+    let mut entities = entities;
     let mut trace = vec![];
     loop {
-	if let Some((prefix, hoop)) = split(&e, &trace) {
+	if let Some((prefix, hoop)) = split(&entities, &trace) {
 	    return (prefix.to_vec(), hoop.to_vec());
 	} else {
-	    let t = e.union(q);
-	    let p = compute_all_owned(&t, rs);
-	    trace.push(e.clone());
-	    e = p;
+	    let t = entities.union(q);
+	    let products = compute_all_owned(&t, rs);
+	    trace.push(entities.clone());
+	    entities = products;
+	}
+    }
+}
+
+// finds the loops by simulating the system
+fn find_only_loop(rs: &Rc<Vec<RSreaction>>, entities: RSset, q: &RSset) -> Vec<RSset> {
+    let mut entities = entities;
+    let mut trace = vec![];
+    loop {
+	if let Some((_prefix, hoop)) = split(&entities, &trace) {
+	    return hoop.to_vec();
+	} else {
+	    let t = entities.union(q);
+	    let products = compute_all_owned(&t, rs);
+	    trace.push(entities.clone());
+	    entities = products;
 	}
     }
 }
 
 // see lollipop
 pub fn lollipops(system: RSsystem) -> Vec<(Vec<RSset>, Vec<RSset>)> {
-    fn filter_delta<'a>(x: (&IdType, &'a RSprocess)) -> Option<&'a RSset> {
-	use super::structure::RSprocess::*;
-	let (id, rest) = x;
-	match rest {
-	    EntitySet{ entities, next_process} => {
-		match &**next_process {
-		    RecursiveIdentifier{ identifier } if identifier == id => {
-			Some(entities)
-		    },
-		    _ => None
-		}
-	    },
-	    _ => None
-	}
-    }
-
-    // FIXME: what? i think we are only interested in "x", not all symbols that
+    // FIXME: i think we are only interested in "x", not all symbols that
     // satisfy X = pre(Q, rec(X))
     let filtered = system.get_delta().iter().filter_map(filter_delta);
 
-    filtered.map(|q| find_loop(system.get_reaction_rules(),
-			       system.get_available_entities().clone(),
-			       q)
-    ).collect::<Vec<_>>()
+    let find_loop_fn = |q| find_loop(system.get_reaction_rules(),
+				     system.get_available_entities().clone(),
+				     q);
+
+    filtered.map(find_loop_fn).collect::<Vec<_>>()
+}
+
+pub fn lollipops_only_loop(system: RSsystem) -> Vec<Vec<RSset>> {
+    // FIXME: i think we are only interested in "x", not all symbols that
+    // satisfy X = pre(Q, rec(X))
+    let filtered = system.get_delta().iter().filter_map(filter_delta);
+
+    let find_loop_fn = |q| find_only_loop(system.get_reaction_rules(),
+				     system.get_available_entities().clone(),
+				     q);
+
+    filtered.map(find_loop_fn).collect::<Vec<_>>()
 }