(* Adrian Pop, adrpo@ida.liu.se, http://www.ida.liu.se/~adrpo *)
(* 2005-01-15 *)
(* problem with exceptions in SML.NET version:
   SML.NET 1.2 build 1102 of Friday, 07 January 2005
	Running on .NET Framework v1.1.4322
	Using assembler in C:\bin\sml.net\bin\v1.1.4322\ilasm.exe
	Using class list tool in C:\bin\sml.net\bin\v1.1.4322\clslist.exe
	Using metadata import tool in C:\bin\sml.net\bin\v1.1.4322\getmeta.exe
   http://www.cl.cam.ac.uk/Research/TSG/SMLNET/ 
*)
(*
 Problem description:
  - exception is ignored in Release version even thou' it should be raised
    + compile in Release and run the exe, it will exit without any problem
  - exception works in Debug version
    + compile in Debug and run the exe, it will raise an error
Output:
adrpo@kafka /cygdrive/c/dev/sml.net.error/RML
$ Release/RML.exe 
unifying: string ?=? string
 the types can be unified 
adrpo@kafka /cygdrive/c/dev/sml.net.error/RML
$ Debug/RML.exe 
unifying: string ?=? string
does not unify!
static elaboration error!
*)


structure RML
  : sig val main: unit -> unit
    end = 
struct
    type ty = string
    datatype tyerr_explanation
      = TY_ERROR of ty * string
      | TY_DIFFER of ty * ty * string
    exception TypeError of tyerr_explanation

    fun tyErrDiffer(ty1, ty2, why) =
    (* this doesn't do raise in Release, if you put a print "raised" before it works *) 
      raise TypeError(TY_DIFFER(ty1, ty2, why))
        
    fun unify(ty1, ty2) = (ty1 = ty2)
		
    fun unify_list(tys1, tys2, ty1, ty2) =
      let fun loop([], []) = (print "\nunifying: [] ?=? []\n"; ())
	    | loop(ty1::tys1, ty2::tys2) = 
			(print "\nunifying: "; 
			 print ty1; print " ?=? "; 
			 print ty2; print "\n"; 
			 unify(ty1, ty2); 
			 (* here it will be loop("list",nil) which 
			    should trigger the last case in the loop *)
			 loop(tys1, tys2)) 
		(* this is actually "called" in the Release version but doesn't raise *)
		(* in Debug version it does the raise *)
		(* this doesn't do raise in Release,  BUT you put a print "before raise" before it works *) 
	    | loop(_, _) = tyErrDiffer(ty1, ty2, " arity ") 
      in 
		loop(tys1, tys2)
      end

	exception StaticElaborationError
	          
    fun elab(exp_taus, pat_taus) =
	   let val _ = unify_list(exp_taus, pat_taus, "", "") 
				   handle exn =>
					((case exn
					of TypeError explain => print "does not unify!\n"
						| StaticElaborationError => () 
						| _ => print "other problems\n");
					raise StaticElaborationError)
	   in
	    (print " the types can be unified ")
	   end
      

    fun main  () = 
    let
		val argz = CommandLine.arguments()
		val _ = elab(["string","list"],["string"]) (* unify these: SHOULDN'T WORK!! for the second *)
				   handle exn =>
					(case exn
					of  StaticElaborationError => (print "static elaboration error!") 
						| _ => print "Other exception!")
		in  
		() 
			handle 
				exn => print ("\nException raised during compilation :" ^ exnMessage exn; OS.Process.exit 0)
	end
end