Re: whither stack traces?

> Many of us on the list would _really_ like to see a working example of 
> this !

I'm not positive this is quite right, but it worked enough for me to get 
something:

     open TextIO List

     fun printStackTrace e =
         let val ss = SMLofNJ.exnHistory e
             val s = General.exnMessage e
             val name = General.exnName e
             val details = if s = name then "" else (" [" ^ s ^ "]")
         in
             print ("uncaught exception " ^ name ^ details ^ "\n");
             case ss of
                  [] => ()
                | (s::ss') => (
                                  print ("  raised at: " ^ s ^ "\n");
                                  app (fn s' => print ("             " ^ 
s' ^ "\n")) ss'
                              )
         end

     fun main(arg:string, args:string list) =
         main'(arg, args) handle e => (printStackTrace e; 1)

I believe the only part of the continuation that exnHistory records is 
the exception handlers that the `raise' passed through, so it's much 
less detailed than a conventional backtrace. I'm not sure if this is the 
same thing the REPL gives you.

For more detailed backtraces, I use the BackTrace module:

     fun main(arg:string, args:string list) =
         BackTrace.monitor(fn () => main'(arg, args))

I add $smlnj-tdp/plugins.cm to my CM file and build with:

     ml-build -Ctdp.instrument=true \$smlnj-tdp/back-trace.cm foo.cm 
Main.main foo.heap

Note that if you want to put the above in a Makefile, you have to use 
make's convention for quoting dollar signs and double the dollar sign:

     ml-build -Ctdp.instrument=true \$$smlnj-tdp/back-trace.cm foo.cm 
Main.main foo.heap

Dave

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