Unknown Pragmas in Ada 9X

Unknown Pragmas in Ada 9X

[cis.ohio-state.edu!magnus.acs.ohio-state.edu!csn!news.usafa.af.mil!kirk!c]

Someone here noted a while back that bad pragmas will be rejected by
compilers in Ada 9X (rather than ignored).  Looking at "Introducing
Ada 9X), this appears to occur when a pragma has bad arguments.  This
all sounds fine.

I want to make sure, however, that an unknown pragma is still ignored.
The description of the change doesn't mention unsupported pragmas, but
it doesn't mention that they are still ignored either...  This is 
important if code is submitted to more than one compiler, or (in my
case) where pragmas are used as annotations for other "tools," not 
necessarily the compiler.  Anyone on the inside know this for sure?

Furthermore, for the ASIS people.  Does the ASIS standard under
discussion imply that pragmas unsupported by the compiler will be
"supported" by ASIS?  (I.e., ASIS packages will be able to process
pragmas even though the compiler ignores them...)

-- 
Christopher A. Warack, Capt, USAF
Computer Science Department, US Air Force Academy

cwarack@kirk.usafa.af.mil                (719) 472-2401

Re: Unknown Pragmas in Ada 9X

[Gene Ouye]

Chris Warack <sys mgr> (cwarack@kirk.usafa.af.mil) wrote:
: Someone here noted a while back that bad pragmas will be rejected by
: compilers in Ada 9X (rather than ignored).  Looking at "Introducing
: Ada 9X), this appears to occur when a pragma has bad arguments.  This
: all sounds fine.

: I want to make sure, however, that an unknown pragma is still ignored.
: The description of the change doesn't mention unsupported pragmas, but
: it doesn't mention that they are still ignored either...  This is 
: important if code is submitted to more than one compiler, or (in my
: case) where pragmas are used as annotations for other "tools," not 
: necessarily the compiler.  Anyone on the inside know this for sure?

I looked in the Annotated Ada 9X Reference Manual Version 3.0 (it's available
via anonymous ftp at ajpo.sei.cmu.edu) and you can rest easy with regard
to "unknown" or unrecognized pragmas.  AARM v3.0 para 2.8(7) states:

"If an implementation does not recognize the name of a pragma, then it has
no effect on the semantics of the program."

Of course, AARM v3.0 is just a draft, so things could change...

(...but this one doesn't seem likely. :-)


Gene Ouye (geneo@rational.com)    Rational, Bethesda, MD
(301) 897-4014

Re: Unknown Pragmas in Ada 9X

[Alex Blakemore]

In article <236r5q$m7e@usafa2.usafa.af.mil> cwarack@kirk.usafa.af.mil (Chris Wa
rack <sys mgr>) writes:
> Furthermore, for the ASIS people.  Does the ASIS standard under
> discussion imply that pragmas unsupported by the compiler will be
> "supported" by ASIS?  (I.e., ASIS packages will be able to process
> pragmas even though the compiler ignores them...)

the ASIS spec has a place for unknown pragmas, but I dont know if the
latest spec _requires_ that they be preserved.  I know an earlier implementatio
n
ignored them.  we should check this.

btw, it would be good to mail things like this to asis@stars.reston.paramax.com
 
so they are brought to the attention of the people working on and using the sta
ndard.
-- 
Alex Blakemore       alex@cs.umd.edu        NeXT mail accepted
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