steve@hubcap.clemson.edu ("Steve" Stevenson) (07/26/90)
What is the status of attempts at the latest standard? What methods are used to specify semantics? Are there any attempts to use any of the ``formal semantics'' methods? -- =============================================================================== Steve (really "D. E.") Stevenson steve@hubcap.clemson.edu Department of Computer Science, (803)656-5880.mabell Clemson University, Clemson, SC 29634-1906
khb@chiba.Eng.Sun.COM (chiba) (07/26/90)
In article <9848@hubcap.clemson.edu> steve@hubcap.clemson.edu ("Steve" Stevenson) writes:
What is the status of attempts at the latest standard?
C became an ANSI standard in December '89.
Fortran 90 is in the midst of ISO processing for offical ISO draft status.
What methods are used to specify semantics?
X3J3 employs english. BNF is provided as an aid.
Are there any attempts to use any of the ``formal semantics'' methods?
It is my understanding that the ISO Modula work uses VDM. Most other
standards bodies, that I am aware of, do not employ "formal semantics"
techniques.
--
Keith H. Bierman |*My thoughts are my own. !! kbierman@Eng.Sun.COM
It's Not My Fault | MTS --Only my work belongs to Sun* khb@chiba.Eng.Sun.COM
I Voted for Bill & | Advanced Languages/Floating Point Group (415 336 2648)
Opus<khb@eng.sun.com> "When the going gets Weird .. the Weird turn PRO"henry@zoo.toronto.edu (Henry Spencer) (07/27/90)
In article <KHB.90Jul25140420@chiba.Eng.Sun.COM> khb@chiba.Eng.Sun.COM (chiba) writes: > Are there any attempts to use any of the ``formal semantics'' methods? > >It is my understanding that the ISO Modula work uses VDM. Most other >standards bodies, that I am aware of, do not employ "formal semantics" >techniques. The problem with formal semantic specifications is that most programmers cannot read them. A standard, ideally, is a contract between the user and the implementor, telling the user what he can count on and what he shouldn't, and the implementor what he is allowed to do and what he is forbidden to even consider. As with any contract, you have a choice of writing it in formal, precise language that only lawyers understand, or doing the best you can on precision while keeping it human-readable. Making a human-language standard precise and unambigous is difficult, but a formal-language standard is inaccessible to many of the people who need it most. Most language designers and standards committees prefer widely-accessible documents. Arguably more programmers *should* be able to read formal specs. The fact is, they can't. One either lives in the real world, or not. Oddly enough, most widely-used languages were designed by people who favored living in the real world. -- NFS: all the nice semantics of MSDOS, | Henry Spencer at U of Toronto Zoology and its performance and security too. | henry@zoo.toronto.edu utzoo!henry
smryan@garth.UUCP (sous-realiste) (08/08/90)
In article <9848@hubcap.clemson.edu> steve@hubcap.clemson.edu ("Steve" Stevenson) writes: >What is the status of attempts at the latest standard? What >methods are used to specify semantics? Are there any attempts to use >any of the ``formal semantics'' methods? Or even formal syntax? -- Her somber eyes consider all ||/+\==/+\|| Steven Ryan that loom and tower, large and tall.||\=/++\=/|| ...!uunet!ingr!apd!smryan Her everyday is always new ||/=\++/=\||...!{apple|pyramid}!garth!smryan and fills her eyes of frail blue. ||\+/==\+/|| 2400 Geng Road, Palo Alto, CA
henry@zoo.toronto.edu (Henry Spencer) (08/08/90)
In article <652@garth.UUCP> smryan@garth.UUCP (sous-realiste) writes: >>What is the status of attempts at the latest standard? What >>methods are used to specify semantics? Are there any attempts to use >>any of the ``formal semantics'' methods? > >Or even formal syntax? Formal syntax notations are normal nowadays (well, I can't speak for the Fortran people :-), but they're normal everywhere else). That does not necessarily mean a yacc grammar, mind you, as there are a lot of variations on good old BNF. -- The 486 is to a modern CPU as a Jules | Henry Spencer at U of Toronto Zoology Verne reprint is to a modern SF novel. | henry@zoo.toronto.edu utzoo!henry
jlg@lanl.gov (Jim Giles) (08/09/90)
From article <1990Aug8.153448.2498@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): > In article <652@garth.UUCP> smryan@garth.UUCP (sous-realiste) writes: > [...] >>>any of the ``formal semantics'' methods? >>Or even formal syntax? > > Formal syntax notations are normal nowadays (well, I can't speak for > the Fortran people :-), but they're normal everywhere else). [...] Well, the Fortran 77 standard gave syntax as "railroad tracks". The notation was actually equivalent to an LR(1) grammar for the language. (The syntactical problems caused by insignificant blanks and misidentified keywords can all be solved by a smart lexer - so the token level syntax is LR(1).) The Fortran 90 syntax is given is a pretty typical BNF notation. I believe that it is again intended to be LR(1) - or even something simpler for the free form input. J. Giles