Re: swank-kawa.scm

[Helmut Eller <eller dot helmut at gmail dot com>]

On Sun, Apr 21 2013, Chuah Teong Leong wrote:

> Hi Helmut Eller,
>
> I've been looking into kawa support within emacs. So far I have slime,
> scheme-complete, paredit set up. I came across this code you wrote.
>
> I have 2 problems that I'm hoping you could help me with.
>
> 1) Compilation
> I'm working on windows and I'm not exactly sure if I got the
> compilation process correct. I ran kawa with -cp to tools.jar and
> kawa.jar and did (compile "swank-kawa.scm" "swank-kawa") from the
> repl. There wasn't any error message and it produced a swank-kawa.zip
> within slime\contrib. I'm wondering if it should have been renamed to
> a jar and included it in the classpath. I haven't done anything yet
> and assume that is how it should be.

Initially I would recommend not to compile the file. You can load the
source file with (require ".../swank-kawa.scm").  Try this from the Kawa
REPL outside of Emacs in a normal shell to minimize confusion.

If you really want to know how to compile, here are some hints:

I think that compile-file is obsolete in Kawa or at least Per Bothner
considers it bad practice. If you use compile-file you should use the
load function instead of require: (load "..swank-kawa.zip").

The recommended way to compile is from the shell with something like
"kawa -C swank-kawa.scm".  Add classpath stuff and other flags as
needed.  This produces .class files like javac does.  These .class files
can then be put in a jar file with the normal jar tool, just like normal
java classes.  To load such a jar, the jar file needs to be in the
classpath and you need to use (import (swank-kawa)) inside Kawa.

>
> 2) Usage
> at the end of the instruction you said
> "Start everything with  M-- M-x slime kawa"
>
> I couldn't quite figure how to do that.
> I did M-x slime and got this
>
> (begin (require "G:/emacs-24.2/lisp/slime/contrib/swank-kawa.scm")
> (start-swank "c:/Users/****/AppData/Local/Temp/slime.13604"))
> Listening for transport dt_socket at address: 49420
> #|kawa:1|# Thread[swank,5,main]
> #|kawa:2|# connection: Socket[addr=/127.0.0.1,port=49424,localport=49423]
> listener: Thread[swank-listener,5,main] 28560412 chan@df11d5 #<environment r0>
> attaching: $PPID 20
> attaching2: com.sun.jdi.ProcessAttach (defaults: pid=, timeout=)
> {pid=pid=$PPID, timeout=timeout=20}
> java.util.ServiceConfigurationError:
> com.sun.tools.attach.spi.AttachProvider: Provider
> sun.tools.attach.WindowsAttachProvider could not be instantiated:
> java.lang.UnsatisfiedLinkError: no attach in java.library.path
> closing socket: ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=49423]
> exception in thread Thread[swank,5,main]: java.lang.Error: mcase failed tmp
> (chan@cc7ed2
>  (error "java.io.IOException: no providers installed" "IOException"
>   ("com.sun.tools.jdi.ProcessAttachingConnector.attach(ProcessAttachingConnector.java:104)"
>    "swank$Mnkawa.attach(swank-kawa.scm:1777)"
>    "swank$Mnkawa.vmAttach(swank-kawa.scm:1758)"


OK, it seems that your setup is mostly correct but it runs in to a
problem in my code.  The function getpid in swank-kawa.scm is supposed
to return the process id of the current process; to my knowledge there's
no portable way to do that in Java.  The code simply assumes that we run
on Linux and uses a Linux specific trick to figure out the pid (that's
where the $PPID comes from in the debug output).  I don't know what the
best trick is on Windows. Maybe steal something from the Clojure people:
https://github.com/pallet/ritz/blob/develop/repl-utils/src/ritz/repl_utils/sys.clj

On Linux
((java.lang.management.ManagementFactory:getRuntimeMXBean):getName)
seems to return something useful. but (java.lang.System:getProperty
"pid") doesn't.

Anyway, if you want to explore this further then I would recommend that
you start swank in Kawa REPL outside of Emacs like so:

  #|kawa:1|# (require "/home/helmut/lisp/slime/contrib/swank-kawa.scm")
  #|kawa:2|# (create-swank-server 4005)
  Listening on port: 4005

Then you can use M-x slime-connect in Emacs to proceed and the Kawa side
should print something like:

  connection: Socket[addr=/127.0.0.1,port=52781,localport=4005]
  listener: Thread[swank-listener,5,main] 11515472 chan@1ea71d4
  #<environment main>
  attaching: 3763 20
  attaching2: com.sun.jdi.ProcessAttach (defaults: pid=, timeout=)
  {pid=pid=3763, timeout=timeout=20}

Helmut