Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!ai.etl.army.mil!mike
From: mike@ai.etl.army.mil (Mike McDonnell)
Newsgroups: comp.lang.c++
Subject: Re: Standards For C++
Message-ID: <188@ai.etl.army.mil>
Date: 3 Oct 88 12:08:36 GMT
References: <255@itivax.UUCP> <6590067@hplsla.HP.COM> <1988Sep29.164824.25390@utzoo.uucp>
Reply-To: mike@ai.etl.army.mil (Mike McDonnell)
Organization: USAETL, Fort Belvoir, Virginia
Lines: 36

In article <1988Sep29.164824.25390@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In practice, in the absence of formal standards processes (e.g. ANSI),
>de-facto standards tend to be set by whatever documents are available.
>At present, we essentially have two levels of standard for the language
>itself:  Bjarne's book, and his paper in the C++ Workshop proceedings
>(which includes multiple inheritance and a number of other things).  The
>formal reference manual he now has in the works will probably supersede
>the latter in the public eye.

Implementations can define standards as well as documentation can.
GNU's "g++" has some good ideas that differ from Stroustrup's book.  In
particular, they have modified the language slightly to allow a LALR(1)
grammar rather than the infinite-lookahead required by "the book".  This
allows better optimization and more "modern" compiler techology, or so
they say.  There are lesser differences as well; as documented with the
distribution.  These ideas should be considered.  Here is the relevant
part of the g++ documentation, complete with a characteristic Stallman
diatribe:

   * The design of the C++ programming language did not take into account the
 usefulness of being able to specify that language using an LALR(1) grammar.
 As a result, in order to correctly parse it, one needs a look-ahead lexical
 analyzer (with infinite lookahead), and a recursive descent parser, guided
 by some good heuristics.  This approach was not taken in GNU C++, because
 it is considered archaic, notoriously difficult to extend syntactically,
 and generally offensive.  GNU C++ uses an LALR(1) grammar so that users can
 easily understand, and readily modify the compiler to suit their needs.
 Free software is useless if it becomes captive to an inaccessible or
 undesirable technology.  However, in providing such a grammar, some
 syntactic forms were lost, most notably old-style C function declarations
 and occasionally function parameters which are declared longhand to be
 pointers to functions are not recognized properly.

-- 
Mike McDonnell at the U.S. Army Engineer Topographic Laboratories, Bldg. 2592
Fort Belvoir, VA 22060-5546   TEL:(202)355-2724   ARPA: mike@ai.etl.army.mil