Cancel button or Status bar

Cancel button or Status bar

[Angela Zhu]

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Hi,

I am using OCaml to develop an interpreter with a GUI.
In the GUI, I have a "run" button, where when you click it, it
will call a function, say "eval prog1".

Some time, the running time of "eval prog1" can be long, and
in case I want to add to the GUI the functionality that,
when click on another "cancel" button, it will terminate the
computation/evaluation immediately. (The user might don't
want to wait until the execution to finish. )

Anyone have some idea how to achieve this?

If this is impractical in OCaml, then how can I generate a
"status bar", which indicates how much of the program
(e.g. in percentage) has been finished, so you can have
an estimation on how much more you need to wait for the program
to finish.

Thanks a lot in advance!

-- 
Regards,
Angela Zhu
------------------------------------------
Dept. of CS, Rice University
http://www.cs.rice.edu/~yz2/
------------------------------------------

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Re: [Caml-list] Cancel button or Status bar

[Dominique Martinet]

Hello,

If it's an OCaml interpreter, I don't think there's a way to evaluate
the time needed automatically, you can compute the complexity yourself
and have a rough evaluation of the compile time, but there's no way a
computer will do it for you without actually evaluating the
expression.

The stopping is easy though; if you use a GUI you probably already
have threads (i.e. when you click on run, it will call the "eval
prog1" function in a thread, so you can keep editing inside of the
GUI). You can save the thread id when you run it, and ask to kill it
when you click on the stop button, and I don't even think it will
raise an exception.

If you're not already using threads, I'm curious and would like to
know how you plan to handle the GUI.

Regards,
Martinet Dominique

PS : O'Reilly's book is a nice place to start if you don't know much
about threads http://caml.inria.fr/pub/docs/oreilly-book/html/book-ora175.html

Re: [Caml-list] Cancel button or Status bar

[Angela Zhu]

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Thanks Dominique!

I was not using threads but I think it is a good idea.

Best regards,
Angela


On Feb 16, 2008 11:26 AM, Dominique Martinet <asmadeus77@gmail.com> wrote:

> Hello,
>
> If it's an OCaml interpreter, I don't think there's a way to evaluate
> the time needed automatically, you can compute the complexity yourself
> and have a rough evaluation of the compile time, but there's no way a
> computer will do it for you without actually evaluating the
> expression.
>
> The stopping is easy though; if you use a GUI you probably already
> have threads (i.e. when you click on run, it will call the "eval
> prog1" function in a thread, so you can keep editing inside of the
> GUI). You can save the thread id when you run it, and ask to kill it
> when you click on the stop button, and I don't even think it will
> raise an exception.
>
> If you're not already using threads, I'm curious and would like to
> know how you plan to handle the GUI.
>
> Regards,
> Martinet Dominique
>
> PS : O'Reilly's book is a nice place to start if you don't know much
> about threads
> http://caml.inria.fr/pub/docs/oreilly-book/html/book-ora175.html
>

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Re: [Caml-list] Cancel button or Status bar

[Angela Zhu]

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On Feb 16, 2008 11:26 AM, Dominique Martinet <asmadeus77@gmail.com> wrote:

> Hello,
>
> If it's an OCaml interpreter, I don't think there's a way to evaluate
> the time needed automatically, you can compute the complexity yourself
> and have a rough evaluation of the compile time, but there's no way a
> computer will do it for you without actually evaluating the
> expression.
>
> The stopping is easy though; if you use a GUI you probably already
> have threads (i.e. when you click on run, it will call the "eval
> prog1" function in a thread, so you can keep editing inside of the
> GUI). You can save the thread id when you run it, and ask to kill it
> when you click on the stop button, and I don't even think it will
> raise an exception.
>
> If you're not already using threads, I'm curious and would like to
> know how you plan to handle the GUI.
>
> Regards,
> Martinet Dominique
>
> PS : O'Reilly's book is a nice place to start if you don't know much
> about threads
> http://caml.inria.fr/pub/docs/oreilly-book/html/book-ora175.html
>

Well, I followed the direction on this page, however, whenever I try to
compile using ocamlc, I got "Unbound module Thread" for the line where I
have:
"Thread.create compute ()"

Anyone knows what can be the problem here?

Here is my compiling flags:

world: $(LIBTARGETS) $(GTKSRCFILES:.ml=.cmo) src/main.ml
    ocamlc $(COMPFLAGS) -thread -custom threads.cma -cclib -lthreads -cclib
-lunix -cclib -lpthread graphics.cma $(LIBTARGETS) $(GTKSRCFILES:.ml=.cmo) \
          $(TKSRCFILES:.ml=.cmo) -o acumen src/main.ml
    @ echo " -- make world (Done)"

world.opt: $(LIBTARGETSOPT) $(GTKSRCFILES:.ml=.cmx)
    ocamlopt -thread threads.cmxa -cclib -lthreads -cclib -lunix -cclib
-lpthread $(COMPFLAGS)  $(LIBTARGETSOPT) $(GTKSRCFILES:.ml=.cmx) \
          src/main.ml -ccopt -Wl,-E -o acumen.opt
    @ echo " -- make world.opt (Done)"


Best,
Angela

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Re: [Caml-list] Cancel button or Status bar

[Dominique Martinet]

Hello,

Using your compiling line, I get an "reference to undefined global 'Unix'",
I've added "unix.cma" / "unix.cmxa" right before the -thread and it
then compiled just fine, and my dummy program worked. (if this still
doesn't work, mind sending everything make outputs ?)

Anyway, I don't know if you actually need all of the libraries the
book makes you load - I've only used "unix.cma -thread threads.cma"
and it worked just fine the couple of times I've used threads (change
.cma to .cmxa for ocamlopt)

Good luck,
Martinet Dominique.