Value::Output(id) => *id = port_id_to_eval(created_port_id),

                _ => unreachable!(),

            }

        }

        // For each transferred port pair set their peer components to the

        // correct values. This will only change the values for the ports of

        // the new component.

        let mut created_component_has_remote_peers = false;

        for pair in opened_port_id_pairs.iter() {

            let creator_port_info = creator_ctx.get_port(pair.creator_handle);

            let created_port_info = created_ctx.get_port_mut(pair.created_handle);

            if created_port_info.peer_comp_id == creator_ctx.id {

                // Port peer is owned by the creator as well

                let created_peer_port_index = opened_port_id_pairs

                    .iter()

                    .position(|v| v.creator_id == creator_port_info.peer_port_id);

                match created_peer_port_index {

                    Some(created_peer_port_index) => {

                        // Peer port moved to the new component as well. So

                        // adjust IDs appropriately.

                        let peer_pair = &opened_port_id_pairs[created_peer_port_index];

                        created_port_info.peer_port_id = peer_pair.created_id;

                        created_port_info.peer_comp_id = reservation.id();

                        todo!("either add 'self peer', or remove that idea from Ctx altogether")

                    },

                    None => {

                        // Peer port remains with creator component.

                        created_port_info.peer_comp_id = creator_ctx.id;

                        created_ctx.add_peer(pair.created_handle, sched_ctx, creator_ctx.id, None);

                    }

                }

            } else {

                // Peer is a different component. We'll deal with sending the

                // appropriate messages later

                let peer_handle = creator_ctx.get_peer_handle(created_port_info.peer_comp_id);

                let peer_info = creator_ctx.get_peer(peer_handle);

                created_ctx.add_peer(pair.created_handle, sched_ctx, peer_info.id, Some(&peer_info.handle));

                created_component_has_remote_peers = true;

            }

        }

        // We'll now actually turn our reservation for a new component into an

        // actual component. Note that we initialize it as "not sleeping" as

        // its initial scheduling might be performed based on `Ack`s in response

        // to message exchanges between remote peers.

        let total_num_ports = opened_port_id_pairs.len() + closed_port_id_pairs.len();

        let component = component::create_component(&sched_ctx.runtime.protocol, definition_id, type_id, arguments, total_num_ports);

        let (created_key, component) = sched_ctx.runtime.finish_create_pdl_component(

            reservation, component, created_ctx, false,

        );

        component.component.on_creation(created_key.downgrade(), sched_ctx);

        // Now modify the creator's ports: remove every transferred port and

        // potentially remove the peer component.

        for pair in opened_port_id_pairs.iter() {

            // Remove peer if appropriate

            let creator_port_info = creator_ctx.get_port(pair.creator_handle);

            let creator_port_index = creator_ctx.get_port_index(pair.creator_handle);

            let creator_peer_comp_id = creator_port_info.peer_comp_id;

            creator_ctx.remove_peer(sched_ctx, pair.creator_handle, creator_peer_comp_id, false);

            creator_ctx.remove_port(pair.creator_handle);

            // Transfer any messages

            if let Some(mut message) = self.inbox_main.remove(creator_port_index) {

                message.data_header.target_port = pair.created_id;

                component.component.adopt_message(&mut component.ctx, message)

            }

            let mut message_index = 0;

            while message_index < self.inbox_backup.len() {

                let message = &self.inbox_backup[message_index];

                if message.data_header.target_port == pair.creator_id {

                    // transfer message

                    let mut message = self.inbox_backup.remove(message_index);

                    message.data_header.target_port = pair.created_id;

                    component.component.adopt_message(&mut component.ctx, message);

                } else {

                    message_index += 1;

                }

            }

            // Handle potential channel between creator and created component

            let created_port_info = component.ctx.get_port(pair.created_handle);

            if created_port_info.peer_comp_id == creator_ctx.id {

                let peer_port_handle = creator_ctx.get_port_handle(created_port_info.peer_port_id);

                let peer_port_info = creator_ctx.get_port_mut(peer_port_handle);

                peer_port_info.peer_comp_id = component.ctx.id;

                peer_port_info.peer_port_id = created_port_info.self_id;

                creator_ctx.add_peer(peer_port_handle, sched_ctx, component.ctx.id, None);

            }

        }

        for pair in closed_port_id_pairs.iter() {

            let port_index = creator_ctx.get_port_index(pair.creator_handle);

            creator_ctx.remove_port(pair.creator_handle);

        }

        // By now all ports and messages have been transferred. If there are any

        // peers that need to be notified about this new component, then we

        // initiate the protocol that will notify everyone here.

        if created_component_has_remote_peers {

            let created_ctx = &component.ctx;

            let schedule_entry_id = self.control.add_schedule_entry(created_ctx.id);

            for pair in opened_port_id_pairs.iter() {

                let port_info = created_ctx.get_port(pair.created_handle);

                if port_info.peer_comp_id != creator_ctx.id && port_info.peer_comp_id != created_ctx.id {

                    let message = self.control.add_reroute_entry(

                        creator_ctx.id, port_info.peer_port_id, port_info.peer_comp_id,

                        pair.creator_id, pair.created_id, created_ctx.id,

                        schedule_entry_id

                    );

                    let peer_handle = created_ctx.get_peer_handle(port_info.peer_comp_id);

                    let peer_info = created_ctx.get_peer(peer_handle);

                    peer_info.handle.send_message(&sched_ctx.runtime, message, true);

                }

            }

        } else {

            // Peer can be scheduled immediately

            sched_ctx.runtime.enqueue_work(created_key);

        }

    }

}

/// Recursively goes through the value group, attempting to find ports.

/// Duplicates will only be added once.

pub(crate) fn find_ports_in_value_group(value_group: &ValueGroup, ports: &mut Vec<PortId>) {

    // Helper to check a value for a port and recurse if needed.

    fn find_port_in_value(group: &ValueGroup, value: &Value, ports: &mut Vec<PortId>) {

        match value {

            Value::Input(port_id) | Value::Output(port_id) => {

                // This is an actual port

                let cur_port = PortId(port_id.id);

                for prev_port in ports.iter() {

                    if *prev_port == cur_port {

                        // Already added

                        return;

                    }

                }

                ports.push(cur_port);

            },

            Value::Array(heap_pos) |

            Value::Message(heap_pos) |

            Value::String(heap_pos) |

            Value::Struct(heap_pos) |

            Value::Union(_, heap_pos) => {

                // Reference to some dynamic thing which might contain ports,

                // so recurse

                let heap_region = &group.regions[*heap_pos as usize];

                for embedded_value in heap_region {

                    find_port_in_value(group, embedded_value, ports);

                }

            },

            _ => {}, // values we don't care about

        }

    }

    // Clear the ports, then scan all the available values

    ports.clear();

    for value in &value_group.values {

        find_port_in_value(value_group, value, ports);

    }

}

struct ValueGroupPortIter<'a> {

    group: &'a mut ValueGroup,

    heap_stack: Vec<(usize, usize)>,

    index: usize,

}

impl<'a> ValueGroupPortIter<'a> {

    fn new(group: &'a mut ValueGroup) -> Self {

        return Self{ group, heap_stack: Vec::new(), index: 0 }

    }

}

struct ValueGroupPortRef {

    id: PortId,

    heap_pos: Option<usize>, // otherwise: on stack

    index: usize,

}

impl<'a> Iterator for ValueGroupPortIter<'a> {

    type Item = ValueGroupPortRef;

    fn next(&mut self) -> Option<Self::Item> {

        // Enter loop that keeps iterating until a port is found

        loop {

            if let Some(pos) = self.heap_stack.last() {

                let (heap_pos, region_index) = *pos;

                if region_index >= self.group.regions[heap_pos].len() {

use super::*;

#[test]

fn test_unconnected_component_error() {

    primitive interact_with_noone() {

        u8[] array = { 5 };

        auto value = array[1];

}

#[test]

fn test_connected_uncommunicating_component_error() {

    primitive crashing_and_burning(out<u32> unused) {

        u8[] array = { 1337 };

        auto value = array[1337];

    }

    primitive sitting_idly_waiting(in<u32> never_providing) {

        sync auto a = get(never_providing);

    }

    composite constructor() {

        channel a -> b;

        new sitting_idly_waiting(b);

        new crashing_and_burning(a);

}

use crate::protocol::*;

use crate::protocol::eval::*;

use crate::runtime2::runtime::*;

use crate::runtime2::component::{CompCtx, CompPDL};

mod error_handling;

pub(crate) fn create_component(rt: &Runtime, module_name: &str, routine_name: &str, args: ValueGroup) {

    let prompt = rt.inner.protocol.new_component(

        module_name.as_bytes(), routine_name.as_bytes(), args

    ).expect("create prompt");

    let reserved = rt.inner.start_create_pdl_component();

    let ctx = CompCtx::new(&reserved);

    let component = Box::new(CompPDL::new(prompt, 0));

    let (key, _) = rt.inner.finish_create_pdl_component(reserved, component, ctx, false);

    rt.inner.enqueue_work(key);

}

pub(crate) fn no_args() -> ValueGroup { ValueGroup::new_stack(Vec::new()) }

#[test]

fn test_component_creation() {

    let pd = ProtocolDescription::parse(b"

    primitive nothing_at_all() {

        s32 a = 5;

        auto b = 5 + a;

    }

    ").expect("compilation");

    let rt = Runtime::new(1, true, pd).unwrap();

    for _i in 0..20 {

        create_component(&rt, "", "nothing_at_all", no_args());

    }

}

#[test]

fn test_component_communication() {

    let pd = ProtocolDescription::parse(b"

    primitive sender(out<u32> o, u32 outside_loops, u32 inside_loops) {

        u32 outside_index = 0;

        while (outside_index < outside_loops) {

            u32 inside_index = 0;

            sync while (inside_index < inside_loops) {

                put(o, inside_index);

                inside_index += 1;

            }

            outside_index += 1;

        }

    }

    primitive receiver(in<u32> i, u32 outside_loops, u32 inside_loops) {

        u32 outside_index = 0;

        while (outside_index < outside_loops) {

            u32 inside_index = 0;

            sync while (inside_index < inside_loops) {

                auto val = get(i);

                while (val != inside_index) {} // infinite loop if incorrect value is received

                inside_index += 1;

            }

            outside_index += 1;

        }

    }

    composite constructor() {

        channel o_orom -> i_orom;

        channel o_mrom -> i_mrom;

        channel o_ormm -> i_ormm;

        channel o_mrmm -> i_mrmm;

        // one round, one message per round

        new sender(o_orom, 1, 1);

        new receiver(i_orom, 1, 1);

        // multiple rounds, one message per round

        new sender(o_mrom, 5, 1);

        new receiver(i_mrom, 5, 1);

        // one round, multiple messages per round

        new sender(o_ormm, 1, 5);

        new receiver(i_ormm, 1, 5);

        // multiple rounds, multiple messages per round

        new sender(o_mrmm, 5, 5);

        new receiver(i_mrmm, 5, 5);

    }").expect("compilation");

    let rt = Runtime::new(3, true, pd).unwrap();

    create_component(&rt, "", "constructor", no_args());

}

#[test]

fn test_intermediate_messenger() {

    let pd = ProtocolDescription::parse(b"

    primitive receiver<T>(in<T> rx, u32 num) {

        auto index = 0;

        while (index < num) {

            sync { auto v = get(rx); }

            index += 1;

        }

    }

    primitive middleman<T>(in<T> rx, out<T> tx, u32 num) {

        auto index = 0;

        while (index < num) {