Modify Instantiable interface to relax port storage type

examples/lut.rs

@@ -35,11 +35,11 @@ impl Instantiable for Lut {
         &self.id
     }
 
-    fn get_input_ports(&self) -> &[Net] {
+    fn get_input_ports(&self) -> impl IntoIterator<Item = &Net> {
         &self.inputs
     }
 
-    fn get_output_ports(&self) -> &[Net] {
+    fn get_output_ports(&self) -> impl IntoIterator<Item = &Net> {
         std::slice::from_ref(&self.output)
     }
 

examples/variants.rs

@@ -17,13 +17,13 @@ impl Instantiable for Gate {
         }
     }
 
-    fn get_input_ports(&self) -> &[Net] {
+    fn get_input_ports(&self) -> impl IntoIterator<Item = &Net> {
         match self {
             Gate::And(_, inputs, _) => inputs,
         }
     }
 
-    fn get_output_ports(&self) -> &[Net] {
+    fn get_output_ports(&self) -> impl IntoIterator<Item = &Net> {
         match self {
             Gate::And(_, _, output) => std::slice::from_ref(output),
         }

src/circuit.rs

@@ -220,10 +220,10 @@ pub trait Instantiable: Clone {
     fn get_name(&self) -> &Identifier;
 
     /// Returns the input ports of the primitive
-    fn get_input_ports(&self) -> &[Net];
+    fn get_input_ports(&self) -> impl IntoIterator<Item = &Net>;
 
     /// Returns the output ports of the primitive
-    fn get_output_ports(&self) -> &[Net];
+    fn get_output_ports(&self) -> impl IntoIterator<Item = &Net>;
 
     /// Returns `true` if the type intakes a parameter with this name.
     fn has_parameter(&self, id: &Identifier) -> bool;
@@ -241,20 +241,34 @@ pub trait Instantiable: Clone {
 
     /// Returns the single output port of the primitive.
     fn get_single_output_port(&self) -> &Net {
-        if self.get_output_ports().len() > 1 {
+        let mut iter = self.get_output_ports().into_iter();
+        let ret = iter.next().expect("Primitive has no output ports");
+        if iter.next().is_some() {
             panic!("Primitive has more than one output port");
         }
-        self.get_input_ports().first().unwrap()
+        ret
     }
 
     /// Returns the output port at the given index.
+    /// # Panics
+    ///
+    /// If the index is out of bounds.
     fn get_output_port(&self, index: usize) -> &Net {
-        &self.get_output_ports()[index]
+        self.get_output_ports()
+            .into_iter()
+            .nth(index)
+            .expect("Index out of bounds for output ports")
     }
 
-    /// Returns the input port of the primitive at index `index`.
+    /// Returns the input port at the given index.
+    /// # Panics
+    ///
+    /// If the index is out of bounds.
     fn get_input_port(&self, index: usize) -> &Net {
-        &self.get_input_ports()[index]
+        self.get_input_ports()
+            .into_iter()
+            .nth(index)
+            .expect("Index out of bounds for output ports")
     }
 }
 

src/netlist.rs

@@ -39,11 +39,11 @@ impl Instantiable for Gate {
         &self.name
     }
 
-    fn get_input_ports(&self) -> &[Net] {
+    fn get_input_ports(&self) -> impl IntoIterator<Item = &Net> {
         &self.inputs
     }
 
-    fn get_output_ports(&self) -> &[Net] {
+    fn get_output_ports(&self) -> impl IntoIterator<Item = &Net> {
         &self.outputs
     }
 
@@ -597,7 +597,7 @@ where
     /// Returns the number of input ports for this circuit node.
     pub fn get_num_input_ports(&self) -> usize {
         if let Some(inst_type) = self.get_instance_type() {
-            inst_type.get_input_ports().len()
+            inst_type.get_input_ports().into_iter().count()
         } else {
             0
         }
@@ -1084,13 +1084,14 @@ where
     ) -> Result<NetRef<I>, String> {
         let nets = inst_type
             .get_output_ports()
-            .iter()
+            .into_iter()
             .map(|pnet| pnet.with_name(format!("{}_{}", inst_name, pnet.get_identifier())))
             .collect::<Vec<_>>();
-        if operands.len() != inst_type.get_input_ports().len() {
+        let input_count = inst_type.get_input_ports().into_iter().count();
+        if operands.len() != input_count {
             return Err(format!(
                 "Expected {} operands, got {}",
-                inst_type.get_input_ports().len(),
+                input_count,
                 operands.len()
             ));
         }
@@ -1106,13 +1107,19 @@ where
     ) -> Result<NetRef<I>, String> {
         let nets = inst_type
             .get_output_ports()
-            .iter()
+            .into_iter()
             .map(|pnet| pnet.with_name(format!("{}_{}", inst_name, pnet.get_identifier())))
             .collect::<Vec<_>>();
         let object = Object::Instance(nets, inst_name, inst_type);
         let index = self.objects.borrow().len();
         let weak = Rc::downgrade(self);
-        let operands = vec![None; object.get_instance_type().unwrap().get_input_ports().len()];
+        let input_count = object
+            .get_instance_type()
+            .unwrap()
+            .get_input_ports()
+            .into_iter()
+            .count();
+        let operands = vec![None; input_count];
         let owned_object = Rc::new(RefCell::new(OwnedObject {
             object,
             owner: weak,
@@ -1857,7 +1864,7 @@ where
                 writeln!(f, "{} (", inst_name.emit_name())?;
                 let level = 4;
                 let indent = " ".repeat(level);
-                for (idx, port) in inst_type.get_input_ports().iter().enumerate() {
+                for (idx, port) in inst_type.get_input_ports().into_iter().enumerate() {
                     let port_name = port.get_identifier().emit_name();
                     if let Some(operand) = owned.operands[idx].as_ref() {
                         let operand = match operand {