Poly/ML June 2016

polyml@lists.polyml.org

5 participants
4 discussions

linking polyML modules to C
by dtopham＠gmail.com 09 Nov '18

09 Nov '18

After more experimenting with GUI in SML, I would like to now try calling an SML module from a C program. That way, the GUI could be built using traditional imperative techniques and the program logic could be written in SML. I see how to call a C function from SML, but and not so clear on how to call an SML function from a C program. I want to build code using polyc and then link with a C main program, but could anyone show me a simple example of calling that function and getting its return value? for example, I have defined: fun sum i n f = if i > n then 0.0 else f i + sum (i+1) n f ; fun int2real x = real x ; in linkToC.sml and #include <iostream> #include <fstream> std::ofstream ofs; int main() { std::cout << sum(1,10,int2real) << std::endl; ofs.open("table.dat"); for(int i = 0; i < 20; i++) ofs << i << '\t' << sum(1,i,int2real) << std::endl; } in linkToC.cpp Looking in the polyc script, I thought adding the -c option might allow me to build the object code which I could then link to the sml functions, but it complains about not having a main. Could someone point me in the right direction? Thanks, Dave On Mon, Dec 15, 2014 at 11:44 AM, David Topham <dtopham at gmail.com> wrote: > David, Thank you so much! I really appreciate your help with this. Your > sample below builds fine with polyc on my system (PolyML 5.5.2). I am using > a minimal Linux distribution named TinyCore ( > http://distro.ibiblio.org/tinycorelinux/) which comes with OpenMotif > 2.3.3 It runs in a virtual machine within another computer only taking up > a few hundred MBs! > > I am going to use it to help my students explore Discrete Math next > semester (this textbook uses SML for that purpose: > http://cs.wheaton.edu/~tvandrun/dmfp/). > > I also found a reasonably current project using PolyML and Motif here: > http://www.lemma-one.com/ProofPower/index/ > > ...however it was built on PolyML 4 and has not yet been ported to the > newer version (e.g. depends on PolyML.commit which no longer seems to be > supported). > > Happy Holidays to everyone in the PolyML community! > > -David Topham > > >> Re: GUI Interface (David Matthews) >> >> I've experimented with building a stand-alone executable with Motif and >> succeeded in getting it to work for me using polyc. (It required >> building Poly/ML with --with-x). I took the example from >> http://www.polyml.org/docs/Motif.html and wrapped it up in a function. >> I did find a problem, though. It looks as though the function has to >> suspend itself with something like Posix.Process.pause otherwise nothing >> happens. I seem to recall that the Motif stuff is handled on a separate >> thread to allow the REPL to continue to accept commands. With a >> stand-alone application there isn't a REPL so without the "pause" it >> terminates immediately. >> >> David >> >> open XWindows ; >> open Motif ; >> >> fun main() = >> let >> val shell = >> XtAppInitialise "" "xed" "Editor" [] [XmNwidth 400, XmNheight 400] ; >> >> val main = XmCreateMainWindow shell "main" [] ; >> >> val bar = XmCreateMenuBar main "bar" [] ; >> >> val fileMenu = XmCreateCascadeButton bar "file" [XmNlabelString "File"] ; >> val editMenu = XmCreateCascadeButton bar "edit" [XmNlabelString "Edit"] ; >> val viewMenu = XmCreateCascadeButton bar "view" [XmNlabelString "View"] ; >> val helpMenu = XmCreateCascadeButton bar "help" [XmNlabelString "Help"] ; >> >> val command = XmCreateText main "command" [XmNeditMode >> XmSINGLE_LINE_EDIT] ; >> >> val hscroll = XmCreateScrollBar main "hscroll" [XmNorientation >> XmHORIZONTAL] ; >> val vscroll = XmCreateScrollBar main "vscroll" [XmNorientation >> XmVERTICAL] ; >> >> val work = XmCreateDrawingArea main "work" [] ; >> in >> >> XtManageChildren [fileMenu, editMenu, viewMenu, helpMenu] ; >> XtManageChildren [bar, command, hscroll, vscroll, work] ; >> >> XmMainWindowSetAreas main bar command hscroll vscroll work ; >> >> XtManageChild main ; >> XtRealizeWidget shell; >> Posix.Process.pause() >> end; >> >> >> ------------------------------ >> >> _______________________________________________ >> polyml mailing list >> polyml at inf.ed.ac.uk >> http://lists.inf.ed.ac.uk/mailman/listinfo/polyml >> >> End of polyml Digest, Vol 110, Issue 12 >> *************************************** >> >> -- >> The University of Edinburgh is a charitable body, registered in >> Scotland, with registration number SC005336. >> >>

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Socket.connectNB
by kostirya＠gmail.com 21 Jun '16

21 Jun '16

Hello, all. Socket.connectNB behaves oddly in Poly/ML. We get raise SysErr immediately after Socket.connectNB to a non-existent server. However, it is a nonblocking connect, so we should get information about unsuccesful connecton only after socket access. The source code is attached and here is the results for Poly/ML: > ./a.out exc in 2 socket: SysErr ("Connection refused", SOME ECONNREFUSED) exc in 3 socket: SysErr ("Connection refused", SOME ECONNREFUSED) exc in 4 socket: SysErr ("Connection refused", SOME ECONNREFUSED) . . ^C > ./a.out exc in 1 socket: SysErr ("Connection refused", SOME ECONNREFUSED) exc in 2 socket: SysErr ("Connection refused", SOME ECONNREFUSED) exc in 3 socket: SysErr ("Connection refused", SOME ECONNREFUSED) exc in 4 socket: SysErr ("Connection refused", SOME ECONNREFUSED) . . ^C We usually get errors in this situation. I've tested on Linix and FreeBSD. MLton and SML/NY don't get errors in the same situation. NIck.

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not printed exception when executed file
by kostirya＠gmail.com 16 Jun '16

16 Jun '16

Hello. Why when executed file, exception is not printed? Is it OK? > cat foo.sml exception Ex fun main () = ( print "Start\n"; raise Ex; print "The End\n" ) > ( cat foo.sml ; echo 'val _ = main ()' ) | poly Poly/ML 5.6 Release Start Exception- Ex raised > polyc foo.sml && ./a.out Start > Best, Nick.

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[isabelle] Opaque ascription for SML code generation
by dm＠prolingua.co.uk 13 Jun '16

13 Jun '16

Pretty-printing isn't part of the ML standard so it's not always clear how to do it properly. There have been various changes over the years. In particular, printing exception packets is difficult because the packet can contain values of types that exist only where the exception is raised. In the example below, "t" may not actually be exported from the signature. So, Poly/ML puts the print function that applies where the exception is raised into the exception packet and uses that if it needs to print the packet. There are no plans to change this. There have been some changes around the printing of types exported through opaque matching. When a structure matches a signature containing a type through opaque matching the semantics says that this creates a new type "name". Poly/ML creates a new ref to hold the pretty print function for the new type. Previously this was initialised to the pretty print function for the implementing type but this was changed in 5.6.1 to default to printing "?". It later became clear that this was too restrictive when the signature contained a datatype (e.g. "test" below) so there was a further change in commit 29985b1c in git master. So now if you install pretty printers both within the structure, (*1*) below, for the exception, and outside the signature (*2*) it will work as you expect. David On 12/06/2016 15:22, Makarius wrote: > After the Isabelle2016 release, we have discontinued SML/NJ and old > versions of Poly/ML, so there is a bit more flexibility now in canonical > patterns for Isabelle/ML. > > The example with structure A3 from above is the difficult one, notably > the situation "does not work (overrides pp for int)". Defining the pp > outside of the structure basically works, but exceptions are not printed > correctly. This is how the problem with opaque ascription was discovered > many years ago, and the abstype solution took over. > > > Here is an update of the example A3 from Stackoverflow above, using > Isabelle2016 with its bundled Poly/ML 5.6: > > ML ? > structure A :> > sig > type t > exception BAD of t > datatype test = Test of t > val a: t > val print: t -> string > end = > struct > > type t = int > > exception BAD of t > datatype test = Test of t > > val a = 42 > > fun print i = "{" ^ Int.toString i ^ "}" > > (*1*) > (*val _ = PolyML.addPrettyPrinter (fn _ => fn _ => fn x => > PolyML.PrettyString (print x))*) > end; > > (*2*) > (*val _ = PolyML.addPrettyPrinter (fn _ => fn _ => fn x => > PolyML.PrettyString (A.print x))*) > ? > > ML ?A.a; A.Test A.a; A.BAD A.a? > > > This leads to a mix of results, depending on the place where the pretty > printer is installed. > > I still don't see how to get a simple and robust pretty printer setup, > so we can't use opaque ascription ? unless David Matthews wants to > refine that again for a future release of Poly/ML. > > > Makarius > >

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Poly/ML June 2016