--- AnyEvent-MP/MP.pm	2009/08/04 22:05:43	1.26
+++ AnyEvent-MP/MP.pm	2009/08/14 23:17:17	1.55
@@ -10,20 +10,44 @@
    NODE       # returns this node's noderef
    NODE $port # returns the noderef of the port
 
+   $SELF      # receiving/own port id in rcv callbacks
+
+   # initialise the node so it can send/receive messages
+   initialise_node;                  # -OR-
+   initialise_node "localhost:4040"; # -OR-
+   initialise_node "slave/", "localhost:4040"
+
+   # ports are message endpoints
+
+   # sending messages
    snd $port, type => data...;
+   snd $port, @msg;
+   snd @msg_with_first_element_being_a_port;
 
-   $SELF      # receiving/own port id in rcv callbacks
+   # creating/using ports, the simple way
+   my $simple_port = port { my @msg = @_; 0 };
+
+   # creating/using ports, tagged message matching
+   my $port = port;
+   rcv $port, ping => sub { snd $_[0], "pong"; 0 };
+   rcv $port, pong => sub { warn "pong received\n"; 0 };
+
+   # create a port on another node
+   my $port = spawn $node, $initfunc, @initdata;
+
+   # monitoring
+   mon $port, $cb->(@msg)      # callback is invoked on death
+   mon $port, $otherport       # kill otherport on abnormal death
+   mon $port, $otherport, @msg # send message on death
 
-   rcv $port, smartmatch => $cb->($port, @msg);
+=head1 CURRENT STATUS
 
-   # examples:
-   rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
-   rcv $port1, pong => sub { warn "pong received\n" };
-   snd $port2, ping => $port1;
-
-   # more, smarter, matches (_any_ is exported by this module)
-   rcv $port, [child_died => $pid] => sub { ...
-   rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
+   AnyEvent::MP            - stable API, should work
+   AnyEvent::MP::Intro     - outdated
+   AnyEvent::MP::Kernel    - WIP
+   AnyEvent::MP::Transport - mostly stable
+
+   stay tuned.
 
 =head1 DESCRIPTION
 
@@ -37,7 +61,7 @@
 
 At the moment, this module family is severly broken and underdocumented,
 so do not use. This was uploaded mainly to reserve the CPAN namespace -
-stay tuned! The basic API should be finished, however.
+stay tuned!
 
 =head1 CONCEPTS
 
@@ -45,31 +69,42 @@
 
 =item port
 
-A port is something you can send messages to with the C<snd> function, and
-you can register C<rcv> handlers with. All C<rcv> handlers will receive
-messages they match, messages will not be queued.
+A port is something you can send messages to (with the C<snd> function).
+
+Ports allow you to register C<rcv> handlers that can match all or just
+some messages. Messages will not be queued.
 
 =item port id - C<noderef#portname>
 
-A port id is always the noderef, a hash-mark (C<#>) as separator, followed
-by a port name (a printable string of unspecified format).
+A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
+separator, and a port name (a printable string of unspecified format). An
+exception is the the node port, whose ID is identical to its node
+reference.
 
 =item node
 
-A node is a single process containing at least one port - the node
-port. You can send messages to node ports to let them create new ports,
-among other things.
-
-Initially, nodes are either private (single-process only) or hidden
-(connected to a master node only). Only when they epxlicitly "become
-public" can you send them messages from unrelated other nodes.
+A node is a single process containing at least one port - the node port,
+which provides nodes to manage each other remotely, and to create new
+ports.
+
+Nodes are either private (single-process only), slaves (connected to a
+master node only) or public nodes (connectable from unrelated nodes).
 
 =item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
 
-A noderef is a string that either uniquely identifies a given node (for
-private and hidden nodes), or contains a recipe on how to reach a given
+A node reference is a string that either simply identifies the node (for
+private and slave nodes), or contains a recipe on how to reach a given
 node (for public nodes).
 
+This recipe is simply a comma-separated list of C<address:port> pairs (for
+TCP/IP, other protocols might look different).
+
+Node references come in two flavours: resolved (containing only numerical
+addresses) or unresolved (where hostnames are used instead of addresses).
+
+Before using an unresolved node reference in a message you first have to
+resolve it.
+
 =back
 
 =head1 VARIABLES/FUNCTIONS
@@ -80,7 +115,7 @@
 
 package AnyEvent::MP;
 
-use AnyEvent::MP::Base;
+use AnyEvent::MP::Kernel;
 
 use common::sense;
 
@@ -90,11 +125,12 @@
 
 use base "Exporter";
 
-our $VERSION = '0.1';
+our $VERSION = $AnyEvent::MP::Kernel::VERSION;
+
 our @EXPORT = qw(
    NODE $NODE *SELF node_of _any_
-   become_slave become_public
-   snd rcv mon kil reg psub
+   resolve_node initialise_node
+   snd rcv mon kil reg psub spawn
    port
 );
 
@@ -108,301 +144,301 @@
 
 =item $thisnode = NODE / $NODE
 
-The C<NODE> function returns, and the C<$NODE> variable contains
-the noderef of the local node. The value is initialised by a call
-to C<become_public> or C<become_slave>, after which all local port
-identifiers become invalid.
-
-=item $noderef = node_of $portid
+The C<NODE> function returns, and the C<$NODE> variable contains the
+noderef of the local node. The value is initialised by a call to
+C<initialise_node>.
 
-Extracts and returns the noderef from a portid or a noderef.
+=item $noderef = node_of $port
 
-=item $SELF
-
-Contains the current port id while executing C<rcv> callbacks or C<psub>
-blocks.
+Extracts and returns the noderef from a port ID or a noderef.
 
-=item SELF, %SELF, @SELF...
+=item initialise_node $noderef, $seednode, $seednode...
 
-Due to some quirks in how perl exports variables, it is impossible to
-just export C<$SELF>, all the symbols called C<SELF> are exported by this
-module, but only C<$SELF> is currently used.
+=item initialise_node "slave/", $master, $master...
 
-=item snd $portid, type => @data
+Before a node can talk to other nodes on the network it has to initialise
+itself - the minimum a node needs to know is it's own name, and optionally
+it should know the noderefs of some other nodes in the network.
 
-=item snd $portid, @msg
+This function initialises a node - it must be called exactly once (or
+never) before calling other AnyEvent::MP functions.
 
-Send the given message to the given port ID, which can identify either
-a local or a remote port, and can be either a string or soemthignt hat
-stringifies a sa port ID (such as a port object :).
+All arguments (optionally except for the first) are noderefs, which can be
+either resolved or unresolved.
 
-While the message can be about anything, it is highly recommended to use a
-string as first element (a portid, or some word that indicates a request
-type etc.).
+The first argument will be looked up in the configuration database first
+(if it is C<undef> then the current nodename will be used instead) to find
+the relevant configuration profile (see L<aemp>). If none is found then
+the default configuration is used. The configuration supplies additional
+seed/master nodes and can override the actual noderef.
 
-The message data effectively becomes read-only after a call to this
-function: modifying any argument is not allowed and can cause many
-problems.
+There are two types of networked nodes, public nodes and slave nodes:
 
-The type of data you can transfer depends on the transport protocol: when
-JSON is used, then only strings, numbers and arrays and hashes consisting
-of those are allowed (no objects). When Storable is used, then anything
-that Storable can serialise and deserialise is allowed, and for the local
-node, anything can be passed.
+=over 4
 
-=item kil $portid[, @reason]
+=item public nodes
 
-Kill the specified port with the given C<@reason>.
+For public nodes, C<$noderef> (supplied either directly to
+C<initialise_node> or indirectly via a profile or the nodename) must be a
+noderef (possibly unresolved, in which case it will be resolved).
+
+After resolving, the node will bind itself on all endpoints and try to
+connect to all additional C<$seednodes> that are specified. Seednodes are
+optional and can be used to quickly bootstrap the node into an existing
+network.
+
+=item slave nodes
+
+When the C<$noderef> (either as given or overriden by the config file)
+is the special string C<slave/>, then the node will become a slave
+node. Slave nodes cannot be contacted from outside and will route most of
+their traffic to the master node that they attach to.
+
+At least one additional noderef is required (either by specifying it
+directly or because it is part of the configuration profile): The node
+will try to connect to all of them and will become a slave attached to the
+first node it can successfully connect to.
 
-If no C<@reason> is specified, then the port is killed "normally" (linked
-ports will not be kileld, or even notified).
+=back
 
-Otherwise, linked ports get killed with the same reason (second form of
-C<mon>, see below).
+This function will block until all nodes have been resolved and, for slave
+nodes, until it has successfully established a connection to a master
+server.
 
-Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
-will be reported as reason C<< die => $@ >>.
+Example: become a public node listening on the guessed noderef, or the one
+specified via C<aemp> for the current node. This should be the most common
+form of invocation for "daemon"-type nodes.
 
-Transport/communication errors are reported as C<< transport_error =>
-$message >>.
+   initialise_node;
 
-=item $guard = mon $portid, $cb->(@reason)
+Example: become a slave node to any of the the seednodes specified via
+C<aemp>.  This form is often used for commandline clients.
 
-=item $guard = mon $portid, $otherport
+   initialise_node "slave/";
 
-=item $guard = mon $portid, $otherport, @msg
+Example: become a slave node to any of the specified master servers. This
+form is also often used for commandline clients.
 
-Monitor the given port and do something when the port is killed.
+   initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
 
-In the first form, the callback is simply called with any number
-of C<@reason> elements (no @reason means that the port was deleted
-"normally"). Note also that I<< the callback B<must> never die >>, so use
-C<eval> if unsure.
+Example: become a public node, and try to contact some well-known master
+servers to become part of the network.
 
-In the second form, the other port will be C<kil>'ed with C<@reason>, iff
-a @reason was specified, i.e. on "normal" kils nothing happens, while
-under all other conditions, the other port is killed with the same reason.
+   initialise_node undef, "master1", "master2";
 
-In the last form, a message of the form C<@msg, @reason> will be C<snd>.
+Example: become a public node listening on port C<4041>.
 
-Example: call a given callback when C<$port> is killed.
+   initialise_node 4041;
 
-   mon $port, sub { warn "port died because of <@_>\n" };
+Example: become a public node, only visible on localhost port 4044.
 
-Example: kill ourselves when C<$port> is killed abnormally.
+   initialise_node "localhost:4044";
 
-   mon $port, $self;
+=item $cv = resolve_node $noderef
 
-Example: send us a restart message another C<$port> is killed.
+Takes an unresolved node reference that may contain hostnames and
+abbreviated IDs, resolves all of them and returns a resolved node
+reference.
 
-   mon $port, $self => "restart";
+In addition to C<address:port> pairs allowed in resolved noderefs, the
+following forms are supported:
 
-=cut
+=over 4
 
-sub mon {
-   my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
+=item the empty string
 
-   my $node = $NODE{$noderef} || add_node $noderef;
+An empty-string component gets resolved as if the default port (4040) was
+specified.
 
-   #TODO: ports must not be references
-   if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
-      if (@_) {
-         # send a kill info message
-         my (@msg) = ($cb, @_);
-         $cb = sub { snd @msg, @_ };
-      } else {
-         # simply kill other port
-         my $port = $cb;
-         $cb = sub { kil $port, @_ if @_ };
-      }
-   }
+=item naked port numbers (e.g. C<1234>)
 
-   $node->monitor ($port, $cb);
+These are resolved by prepending the local nodename and a colon, to be
+further resolved.
 
-   defined wantarray
-      and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
-}
+=item hostnames (e.g. C<localhost:1234>, C<localhost>)
 
-=item $guard = mon_guard $port, $ref, $ref...
+These are resolved by using AnyEvent::DNS to resolve them, optionally
+looking up SRV records for the C<aemp=4040> port, if no port was
+specified.
 
-Monitors the given C<$port> and keeps the passed references. When the port
-is killed, the references will be freed.
+=back
 
-Optionally returns a guard that will stop the monitoring.
+=item $SELF
 
-This function is useful when you create e.g. timers or other watchers and
-want to free them when the port gets killed:
+Contains the current port id while executing C<rcv> callbacks or C<psub>
+blocks.
 
-  $port->rcv (start => sub {
-     my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
-        undef $timer if 0.9 < rand;
-     });
-  });
+=item SELF, %SELF, @SELF...
 
-=cut
+Due to some quirks in how perl exports variables, it is impossible to
+just export C<$SELF>, all the symbols called C<SELF> are exported by this
+module, but only C<$SELF> is currently used.
 
-sub mon_guard {
-   my ($port, @refs) = @_;
+=item snd $port, type => @data
 
-   mon $port, sub { 0 && @refs }
-}
+=item snd $port, @msg
 
-=item lnk $port1, $port2
+Send the given message to the given port ID, which can identify either
+a local or a remote port, and must be a port ID.
 
-Link two ports. This is simply a shorthand for:
+While the message can be about anything, it is highly recommended to use a
+string as first element (a port ID, or some word that indicates a request
+type etc.).
 
-   mon $port1, $port2;
-   mon $port2, $port1;
+The message data effectively becomes read-only after a call to this
+function: modifying any argument is not allowed and can cause many
+problems.
 
-It means that if either one is killed abnormally, the other one gets
-killed as well.
+The type of data you can transfer depends on the transport protocol: when
+JSON is used, then only strings, numbers and arrays and hashes consisting
+of those are allowed (no objects). When Storable is used, then anything
+that Storable can serialise and deserialise is allowed, and for the local
+node, anything can be passed.
 
 =item $local_port = port
 
-Create a new local port object that supports message matching.
+Create a new local port object and returns its port ID. Initially it has
+no callbacks set and will throw an error when it receives messages.
 
-=item $portid = port { my @msg = @_; $finished }
+=item $local_port = port { my @msg = @_ }
 
-Creates a "mini port", that is, a very lightweight port without any
-pattern matching behind it, and returns its ID.
+Creates a new local port, and returns its ID. Semantically the same as
+creating a port and calling C<rcv $port, $callback> on it.
 
-The block will be called for every message received on the port. When the
-callback returns a true value its job is considered "done" and the port
-will be destroyed. Otherwise it will stay alive.
+The block will be called for every message received on the port, with the
+global variable C<$SELF> set to the port ID. Runtime errors will cause the
+port to be C<kil>ed. The message will be passed as-is, no extra argument
+(i.e. no port ID) will be passed to the callback.
 
-The message will be passed as-is, no extra argument (i.e. no port id) will
-be passed to the callback.
+If you want to stop/destroy the port, simply C<kil> it:
 
-If you need the local port id in the callback, this works nicely:
-
-   my $port; $port = miniport {
-      snd $otherport, reply => $port;
+   my $port = port {
+      my @msg = @_;
+      ...
+      kil $SELF;
    };
 
 =cut
 
+sub rcv($@);
+
+sub _kilme {
+   die "received message on port without callback";
+}
+
 sub port(;&) {
    my $id = "$UNIQ." . $ID++;
    my $port = "$NODE#$id";
 
-   if (@_) {
-      my $cb = shift;
-      $PORT{$id} = sub {
-         local $SELF = $port;
-         eval {
-            &$cb
-               and kil $id;
-         };
-         _self_die if $@;
-      };
-   } else {
-      my $self = bless {
-         id    => "$NODE#$id",
-      }, "AnyEvent::MP::Port";
-
-      $PORT_DATA{$id} = $self;
-      $PORT{$id} = sub {
-         local $SELF = $port;
-
-         eval {
-            for (@{ $self->{rc0}{$_[0]} }) {
-               $_ && &{$_->[0]}
-                  && undef $_;
-            }
-
-            for (@{ $self->{rcv}{$_[0]} }) {
-               $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
-                  && &{$_->[0]}
-                  && undef $_;
-            }
-
-            for (@{ $self->{any} }) {
-               $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
-                  && &{$_->[0]}
-                  && undef $_;
-            }
-         };
-         _self_die if $@;
-      };
-   }
+   rcv $port, shift || \&_kilme;
 
    $port
 }
 
-=item reg $portid, $name
-
-Registers the given port under the name C<$name>. If the name already
-exists it is replaced.
+=item rcv $local_port, $callback->(@msg)
 
-A port can only be registered under one well known name.
+Replaces the default callback on the specified port. There is no way to
+remove the default callback: use C<sub { }> to disable it, or better
+C<kil> the port when it is no longer needed.
 
-A port automatically becomes unregistered when it is killed.
+The global C<$SELF> (exported by this module) contains C<$port> while
+executing the callback. Runtime errors during callback execution will
+result in the port being C<kil>ed.
 
-=cut
+The default callback received all messages not matched by a more specific
+C<tag> match.
 
-sub reg(@) {
-   my ($portid, $name) = @_;
+=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
 
-   $REG{$name} = $portid;
-}
+Register (or replace) callbacks to be called on messages starting with the
+given tag on the given port (and return the port), or unregister it (when
+C<$callback> is C<$undef> or missing). There can only be one callback
+registered for each tag.
 
-=item rcv $portid, tagstring        => $callback->(@msg), ...
+The original message will be passed to the callback, after the first
+element (the tag) has been removed. The callback will use the same
+environment as the default callback (see above).
 
-=item rcv $portid, $smartmatch      => $callback->(@msg), ...
+Example: create a port and bind receivers on it in one go.
 
-=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
+  my $port = rcv port,
+     msg1 => sub { ... },
+     msg2 => sub { ... },
+  ;
 
-Register callbacks to be called on matching messages on the given port.
+Example: create a port, bind receivers and send it in a message elsewhere
+in one go:
 
-The callback has to return a true value when its work is done, after
-which is will be removed, or a false value in which case it will stay
-registered.
+   snd $otherport, reply =>
+      rcv port,
+         msg1 => sub { ... },
+         ...
+   ;
 
-The global C<$SELF> (exported by this module) contains C<$portid> while
-executing the callback.
+Example: temporarily register a rcv callback for a tag matching some port
+(e.g. for a rpc reply) and unregister it after a message was received.
 
-Runtime errors wdurign callback execution will result in the port being
-C<kil>ed.
+   rcv $port, $otherport => sub {
+      my @reply = @_;
 
-If the match is an array reference, then it will be matched against the
-first elements of the message, otherwise only the first element is being
-matched.
-
-Any element in the match that is specified as C<_any_> (a function
-exported by this module) matches any single element of the message.
-
-While not required, it is highly recommended that the first matching
-element is a string identifying the message. The one-string-only match is
-also the most efficient match (by far).
+      rcv $SELF, $otherport;
+   };
 
 =cut
 
 sub rcv($@) {
-   my ($noderef, $port) = split /#/, shift, 2;
+   my $port = shift;
+   my ($noderef, $portid) = split /#/, $port, 2;
 
    ($NODE{$noderef} || add_node $noderef) == $NODE{""}
-      or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
+      or Carp::croak "$port: rcv can only be called on local ports, caught";
 
-   my $self = $PORT_DATA{$port}
-      or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
+   while (@_) {
+      if (ref $_[0]) {
+         if (my $self = $PORT_DATA{$portid}) {
+            "AnyEvent::MP::Port" eq ref $self
+               or Carp::croak "$port: rcv can only be called on message matching ports, caught";
+
+            $self->[2] = shift;
+         } else {
+            my $cb = shift;
+            $PORT{$portid} = sub {
+               local $SELF = $port;
+               eval { &$cb }; _self_die if $@;
+            };
+         }
+      } elsif (defined $_[0]) {
+         my $self = $PORT_DATA{$portid} ||= do {
+            my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port";
+
+            $PORT{$portid} = sub {
+               local $SELF = $port;
+
+               if (my $cb = $self->[1]{$_[0]}) {
+                  shift;
+                  eval { &$cb }; _self_die if $@;
+               } else {
+                  &{ $self->[0] };
+               }
+            };
 
-   "AnyEvent::MP::Port" eq ref $self
-      or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
+            $self
+         };
 
-   while (@_) {
-      my ($match, $cb) = splice @_, 0, 2;
+         "AnyEvent::MP::Port" eq ref $self
+            or Carp::croak "$port: rcv can only be called on message matching ports, caught";
 
-      if (!ref $match) {
-         push @{ $self->{rc0}{$match}      }, [$cb];
-      } elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
-         my ($type, @match) = @$match;
-         @match
-            ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
-            : push @{ $self->{rc0}{$match->[0]} }, [$cb];
-      } else {
-         push @{ $self->{any}              }, [$cb, $match];
+         my ($tag, $cb) = splice @_, 0, 2;
+
+         if (defined $cb) {
+            $self->[1]{$tag} = $cb;
+         } else {
+            delete $self->[1]{$tag};
+         }
       }
    }
+
+   $port
 }
 
 =item $closure = psub { BLOCK }
@@ -443,27 +479,200 @@
    }
 }
 
-=back
+=item $guard = mon $port, $cb->(@reason)
 
-=head1 FUNCTIONS FOR NODES
+=item $guard = mon $port, $rcvport
 
-=over 4
+=item $guard = mon $port
+
+=item $guard = mon $port, $rcvport, @msg
+
+Monitor the given port and do something when the port is killed or
+messages to it were lost, and optionally return a guard that can be used
+to stop monitoring again.
+
+C<mon> effectively guarantees that, in the absence of hardware failures,
+that after starting the monitor, either all messages sent to the port
+will arrive, or the monitoring action will be invoked after possible
+message loss has been detected. No messages will be lost "in between"
+(after the first lost message no further messages will be received by the
+port). After the monitoring action was invoked, further messages might get
+delivered again.
+
+In the first form (callback), the callback is simply called with any
+number of C<@reason> elements (no @reason means that the port was deleted
+"normally"). Note also that I<< the callback B<must> never die >>, so use
+C<eval> if unsure.
+
+In the second form (another port given), the other port (C<$rcvport>)
+will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
+"normal" kils nothing happens, while under all other conditions, the other
+port is killed with the same reason.
+
+The third form (kill self) is the same as the second form, except that
+C<$rvport> defaults to C<$SELF>.
+
+In the last form (message), a message of the form C<@msg, @reason> will be
+C<snd>.
+
+As a rule of thumb, monitoring requests should always monitor a port from
+a local port (or callback). The reason is that kill messages might get
+lost, just like any other message. Another less obvious reason is that
+even monitoring requests can get lost (for exmaple, when the connection
+to the other node goes down permanently). When monitoring a port locally
+these problems do not exist.
+
+Example: call a given callback when C<$port> is killed.
+
+   mon $port, sub { warn "port died because of <@_>\n" };
+
+Example: kill ourselves when C<$port> is killed abnormally.
+
+   mon $port;
+
+Example: send us a restart message when another C<$port> is killed.
+
+   mon $port, $self => "restart";
+
+=cut
+
+sub mon {
+   my ($noderef, $port) = split /#/, shift, 2;
+
+   my $node = $NODE{$noderef} || add_node $noderef;
+
+   my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,';
+
+   unless (ref $cb) {
+      if (@_) {
+         # send a kill info message
+         my (@msg) = ($cb, @_);
+         $cb = sub { snd @msg, @_ };
+      } else {
+         # simply kill other port
+         my $port = $cb;
+         $cb = sub { kil $port, @_ if @_ };
+      }
+   }
+
+   $node->monitor ($port, $cb);
+
+   defined wantarray
+      and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
+}
+
+=item $guard = mon_guard $port, $ref, $ref...
+
+Monitors the given C<$port> and keeps the passed references. When the port
+is killed, the references will be freed.
+
+Optionally returns a guard that will stop the monitoring.
+
+This function is useful when you create e.g. timers or other watchers and
+want to free them when the port gets killed:
+
+  $port->rcv (start => sub {
+     my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
+        undef $timer if 0.9 < rand;
+     });
+  });
+
+=cut
+
+sub mon_guard {
+   my ($port, @refs) = @_;
+
+   #TODO: mon-less form?
+
+   mon $port, sub { 0 && @refs }
+}
+
+=item kil $port[, @reason]
+
+Kill the specified port with the given C<@reason>.
+
+If no C<@reason> is specified, then the port is killed "normally" (linked
+ports will not be kileld, or even notified).
 
-=item become_public endpoint...
+Otherwise, linked ports get killed with the same reason (second form of
+C<mon>, see below).
 
-Tells the node to become a public node, i.e. reachable from other nodes.
+Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
+will be reported as reason C<< die => $@ >>.
 
-If no arguments are given, or the first argument is C<undef>, then
-AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
-local nodename resolves to.
-
-Otherwise the first argument must be an array-reference with transport
-endpoints ("ip:port", "hostname:port") or port numbers (in which case the
-local nodename is used as hostname). The endpoints are all resolved and
-will become the node reference.
+Transport/communication errors are reported as C<< transport_error =>
+$message >>.
 
 =cut
 
+=item $port = spawn $node, $initfunc[, @initdata]
+
+Creates a port on the node C<$node> (which can also be a port ID, in which
+case it's the node where that port resides).
+
+The port ID of the newly created port is return immediately, and it is
+permissible to immediately start sending messages or monitor the port.
+
+After the port has been created, the init function is
+called. This function must be a fully-qualified function name
+(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
+program, use C<::name>.
+
+If the function doesn't exist, then the node tries to C<require>
+the package, then the package above the package and so on (e.g.
+C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
+exists or it runs out of package names.
+
+The init function is then called with the newly-created port as context
+object (C<$SELF>) and the C<@initdata> values as arguments.
+
+A common idiom is to pass your own port, monitor the spawned port, and
+in the init function, monitor the original port. This two-way monitoring
+ensures that both ports get cleaned up when there is a problem.
+
+Example: spawn a chat server port on C<$othernode>.
+
+   # this node, executed from within a port context:
+   my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
+   mon $server;
+
+   # init function on C<$othernode>
+   sub connect {
+      my ($srcport) = @_;
+
+      mon $srcport;
+
+      rcv $SELF, sub {
+         ...
+      };
+   }
+
+=cut
+
+sub _spawn {
+   my $port = shift;
+   my $init = shift;
+
+   local $SELF = "$NODE#$port";
+   eval {
+      &{ load_func $init }
+   };
+   _self_die if $@;
+}
+
+sub spawn(@) {
+   my ($noderef, undef) = split /#/, shift, 2;
+
+   my $id = "$RUNIQ." . $ID++;
+
+   $_[0] =~ /::/
+      or Carp::croak "spawn init function must be a fully-qualified name, caught";
+
+   snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
+
+   "$noderef#$id"
+}
+
 =back
 
 =head1 NODE MESSAGES
@@ -473,6 +682,8 @@
 message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
 the remaining arguments are simply the message data.
 
+While other messages exist, they are not public and subject to change.
+
 =over 4
 
 =cut
@@ -512,9 +723,17 @@
 
 =head1 AnyEvent::MP vs. Distributed Erlang
 
-AnyEvent::MP got lots of its ideas from distributed erlang. Despite the
-similarities (erlang node == aemp node, erlang process == aemp port and so
-on), there are also some important differences:
+AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
+== aemp node, Erlang process == aemp port), so many of the documents and
+programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
+sample:
+
+   http://www.Erlang.se/doc/programming_rules.shtml
+   http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
+   http://Erlang.org/download/Erlang-book-part1.pdf      # chapters 5 and 6
+   http://Erlang.org/download/armstrong_thesis_2003.pdf  # chapters 4 and 5
+
+Despite the similarities, there are also some important differences:
 
 =over 4
 
@@ -524,21 +743,41 @@
 same way. AEMP relies on each node knowing it's own address(es), with
 convenience functionality.
 
+This means that AEMP requires a less tightly controlled environment at the
+cost of longer node references and a slightly higher management overhead.
+
+=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
+uses "local ports are like remote ports".
+
+The failure modes for local ports are quite different (runtime errors
+only) then for remote ports - when a local port dies, you I<know> it dies,
+when a connection to another node dies, you know nothing about the other
+port.
+
+Erlang pretends remote ports are as reliable as local ports, even when
+they are not.
+
+AEMP encourages a "treat remote ports differently" philosophy, with local
+ports being the special case/exception, where transport errors cannot
+occur.
+
 =item * Erlang uses processes and a mailbox, AEMP does not queue.
 
-Erlang uses processes that selctively receive messages, and therefore
-needs a queue. AEMP is event based, queuing messages would serve no useful
-purpose.
+Erlang uses processes that selectively receive messages, and therefore
+needs a queue. AEMP is event based, queuing messages would serve no
+useful purpose. For the same reason the pattern-matching abilities of
+AnyEvent::MP are more limited, as there is little need to be able to
+filter messages without dequeing them.
 
-(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
+(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
 
 =item * Erlang sends are synchronous, AEMP sends are asynchronous.
 
-Sending messages in erlang is synchronous and blocks the process. AEMP
-sends are immediate, connection establishment is handled in the
-background.
+Sending messages in Erlang is synchronous and blocks the process (and
+so does not need a queue that can overflow). AEMP sends are immediate,
+connection establishment is handled in the background.
 
-=item * Erlang can silently lose messages, AEMP cannot.
+=item * Erlang suffers from silent message loss, AEMP does not.
 
 Erlang makes few guarantees on messages delivery - messages can get lost
 without any of the processes realising it (i.e. you send messages a, b,
@@ -547,10 +786,10 @@
 AEMP guarantees correct ordering, and the guarantee that there are no
 holes in the message sequence.
 
-=item * In erlang, processes can be declared dead and later be found to be
+=item * In Erlang, processes can be declared dead and later be found to be
 alive.
 
-In erlang it can happen that a monitored process is declared dead and
+In Erlang it can happen that a monitored process is declared dead and
 linked processes get killed, but later it turns out that the process is
 still alive - and can receive messages.
 
@@ -560,9 +799,9 @@
 
 =item * Erlang can send messages to the wrong port, AEMP does not.
 
-In erlang it is quite possible that a node that restarts reuses a process
-ID known to other nodes for a completely different process, causing
-messages destined for that process to end up in an unrelated process.
+In Erlang it is quite likely that a node that restarts reuses a process ID
+known to other nodes for a completely different process, causing messages
+destined for that process to end up in an unrelated process.
 
 AEMP never reuses port IDs, so old messages or old port IDs floating
 around in the network will not be sent to an unrelated port.
@@ -573,6 +812,74 @@
 AEMP can use a proven protocol - SSL/TLS - to protect connections and
 securely authenticate nodes.
 
+=item * The AEMP protocol is optimised for both text-based and binary
+communications.
+
+The AEMP protocol, unlike the Erlang protocol, supports both
+language-independent text-only protocols (good for debugging) and binary,
+language-specific serialisers (e.g. Storable).
+
+It has also been carefully designed to be implementable in other languages
+with a minimum of work while gracefully degrading fucntionality to make the
+protocol simple.
+
+=item * AEMP has more flexible monitoring options than Erlang.
+
+In Erlang, you can chose to receive I<all> exit signals as messages
+or I<none>, there is no in-between, so monitoring single processes is
+difficult to implement. Monitoring in AEMP is more flexible than in
+Erlang, as one can choose between automatic kill, exit message or callback
+on a per-process basis.
+
+=item * Erlang tries to hide remote/local connections, AEMP does not.
+
+Monitoring in Erlang is not an indicator of process death/crashes,
+as linking is (except linking is unreliable in Erlang).
+
+In AEMP, you don't "look up" registered port names or send to named ports
+that might or might not be persistent. Instead, you normally spawn a port
+on the remote node. The init function monitors the you, and you monitor
+the remote port. Since both monitors are local to the node, they are much
+more reliable.
+
+This also saves round-trips and avoids sending messages to the wrong port
+(hard to do in Erlang).
+
+=back
+
+=head1 RATIONALE
+
+=over 4
+
+=item Why strings for ports and noderefs, why not objects?
+
+We considered "objects", but found that the actual number of methods
+thatc an be called are very low. Since port IDs and noderefs travel over
+the network frequently, the serialising/deserialising would add lots of
+overhead, as well as having to keep a proxy object.
+
+Strings can easily be printed, easily serialised etc. and need no special
+procedures to be "valid".
+
+And a a miniport consists of a single closure stored in a global hash - it
+can't become much cheaper.
+
+=item Why favour JSON, why not real serialising format such as Storable?
+
+In fact, any AnyEvent::MP node will happily accept Storable as framing
+format, but currently there is no way to make a node use Storable by
+default.
+
+The default framing protocol is JSON because a) JSON::XS is many times
+faster for small messages and b) most importantly, after years of
+experience we found that object serialisation is causing more problems
+than it gains: Just like function calls, objects simply do not travel
+easily over the network, mostly because they will always be a copy, so you
+always have to re-think your design.
+
+Keeping your messages simple, concentrating on data structures rather than
+objects, will keep your messages clean, tidy and efficient.
+
 =back
 
 =head1 SEE ALSO