Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: Include language bindings? Re: Draft Standard Text, V02.1



I think to study the algebraic properties of intervals and make sure these
semantics are clearly delineated in the standard will be helpful along this
direction. For example, if an implementation violates the algebraic
properties, then it would be clear the implementation is non-conforming.

Also, if some sorts of expression rearrangement are allowed, this will
particularly ensure various compiler optimizations by different vendors will be more consistent accross implementations.

Nate


----- Original Message ----- From: "Marco Nehmeier" <nehmeier@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: "Rudnei Cunha" <rudnei.cunha@xxxxxxxxx>
Cc: "stds-1788" <stds-1788@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, March 16, 2010 7:55 AM
Subject: Re: Include language bindings? Re: Draft Standard Text, V02.1


I think that it's not enough to specify the operation/function by its own.
The big problem with different languages is the different compiler
optimization. Hence, we have to take care about a similar evaluation of
interval expressions (see Jürgens comment "An expression shall be executed
as it is written...").

Best regards,

Marco

Rudnei Cunha schrieb:
Dear colleagues,

I would suggest we could provide a pseudo-language binding, in that we
could define, for each operation/function, the input(s) and output(s),
and how the operation/function should behave. That would be part of the
standard and specific language bindings would be written on top of that,
together with the language (Fortran, C, Ada, other) standards committee.

Regards,
Rudnei

2010/3/16 "Prof.Dr. Jürgen Wolff von Gudenberg"
<wolff@xxxxxxxxxxxxxxxxxxxxxxxxxxx
<mailto:wolff@xxxxxxxxxxxxxxxxxxxxxxxxxxx>>

    I completely agree with Dan's plea for languge bindings.
    I think we can formulate rules not depending on a particular
language.
      "The basic operations are provide as functions or operators .."
      "An expression shall be executed as it is written..."

    In my view P1788 is not a pure hardware standard, although I would
    like to have all functionality in hardware. In the mean time there
    will be software implementations conforming to the standards and
    disseminating the use of intervals.
    Hopefully,
    Juergen

    John Pryce schrieb:

        P1788, Dan

        On 15 Mar 2010, at 16:34, Dan Zuras Intervals wrote:
         That's a good question.

                Looking at IEEE 754-1985, one sees that it was a decade
                or more
                after the hardware standard was in use before there were
                language
                bindings.  Can including language bindings help the
process?
                     Emphatically yes.

                   It was more than 2 decades that 754 lived without
                   standard language bindings & during that time a lot
                   of compilers found 'imaginative' ways to interpret
                   the meaning of the seemingly most obvious things,
                   like '+' & '*'.

                   Some of those interpretations were just 'different'.

                   Some were flat out wrong...
               Dan has long argued this point, and I am persuaded by him.
We
        need language bindings. This is what the P1788 Subgroup
        "Expression Rearrangement" is really about. Can it wake from
        sleep and address this please?

        This is tricky, because by the nature  of language bindings I
        think we, acting alone, can't create normative text on this. Or
        would be unwise to do so. That can only be done in collaboration
        with a relevant language standardization committee. If my health
        is spared to me I intend to join the Fortran committee when our
        work is near completion.

        But if we produce a P1788 clause of _recommendations_ on this
        topic, they will carry a lot of weight. We should then be ready
        to revise it a year or two or three later in the light of
        experience in language committees.

        Regards

        John



--
     o           Marco Nehmeier, Lehrstuhl fuer Informatik II
    / \          Universitaet Wuerzburg, Am Hubland, D-97074 Wuerzburg
InfoII o         Tel.: +49 931 / 31 88684
  / \  Uni       E-Mail: nehmeier@xxxxxxxxxxxxxxxxxxxxxxxxxxx
 o   o Wuerzburg