diff --git a/src/ext/mod.rs b/src/ext/mod.rs
index 94b6222..2e067fa 100644
--- a/src/ext/mod.rs
+++ b/src/ext/mod.rs
@@ -218,12 +218,38 @@ static_assert!(1+1==2; "static assertion test");
     };
 }
 
+/// Run each expression in sequence then return the result of the first one.
+///
+/// # Example
+/// ```
+/// # use mtfse::prog1;
+/// assert_eq!(prog1 {
+///  1 + 2;
+///  println!("Done thing");
+///  4 + 5;
+/// }, 3);
+/// ```
 #[macro_export] macro_rules! prog1 {
-    ($first:expr, $($rest:expr);+ $(;)?) => {
-	($first, $( $rest ),+).0
+    ($first:expr; $($rest:expr);* $(;)?) => {
+	($first, $( $rest ),*).0
     }
 }
 
+/// Helper to create an `std::io::Error` structure.
+///
+/// # Example
+/// ```
+/// # use mtfse::io_err;
+/// let err = io_err!(Other, "some error");
+/// ```
+#[macro_export] macro_rules! io_err {
+    ($kind:ident, $msg:expr) => {
+	::std::io::Error::new(::std::io::ErrorKind::$kind, $msg)
+    };
+    ($msg:expr) => (io_err!(Other, $msg));
+}
+
+
 
 pub trait UnwrapInfallible<T>
 {
diff --git a/src/main.rs b/src/main.rs
index 381d099..52749e4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,13 +15,6 @@ use jemallocator::Jemalloc;
 #[global_allocator]
 static GLOBAL: Jemalloc = Jemalloc;
 
-macro_rules! io_err {
-    ($kind:ident, $msg:expr) => {
-	::std::io::Error::new(::std::io::ErrorKind::$kind, $msg)
-    };
-    ($msg:expr) => (io_err!(Other, $msg));
-}
-
 // Utils
 mod ext;
 use ext::*;
diff --git a/src/service/command.rs b/src/service/command.rs
index caa2f95..982f4c4 100644
--- a/src/service/command.rs
+++ b/src/service/command.rs
@@ -30,6 +30,7 @@ pub struct Command
     resp: oneshot::Receiver<Option<Response>>,
 }
 
+
 impl fmt::Display for Command
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
diff --git a/src/service/mod.rs b/src/service/mod.rs
index e8bfd4b..f14d569 100644
--- a/src/service/mod.rs
+++ b/src/service/mod.rs
@@ -6,11 +6,16 @@ use tokio::sync::{
     Mutex,
     
     mpsc,
+    oneshot,
 };
 
 pub mod command;
+use command::{
+    CommandKind,
+    CommandID,
+};
 
-/// Handle to a running service
+/// Handle to a running service. Can be used to join it or create `Channel`s.
 #[derive(Debug)]
 pub struct Handle
 {
@@ -18,21 +23,38 @@ pub struct Handle
 }
 
 #[derive(Debug)]
-struct CommInner
+struct ChannelInner
+{
+
+}
+
+
+/// The side of a `command::Command` that the running service sees.
+#[derive(Debug)]
+struct Request
 {
+    /// ID that corresponds to the returned `command::Command` from the `send()` function of `Channel`.
+    id: CommandID,
+    /// The actual command sent by the user.
+    kind: CommandKind,
 
+    /// Optional response sender.
+    ///
+    /// Just dropping this is the same as sending `None` as far as the user sees.
+    resp: oneshot::Sender<Option<command::Response>>,    
 }
 
-/// Communicate with a running service
+/// Communicates with a running service
 #[derive(Debug, Clone)]
-pub struct Comm{
-    inner: Arc<CommInner>,
+pub struct Channel{
+    inner: Arc<ChannelInner>,
 
-    tx: mpsc::Sender<()>,
+    
+    tx: mpsc::Sender<Request>,
 }
 
-impl Eq for Comm{}
-impl PartialEq for Comm {
+impl Eq for Channel{}
+impl PartialEq for Channel {
     #[inline] fn eq(&self, other: &Self) -> bool
     {
 	Arc::ptr_eq(&self.inner, &other.inner)