Re: bin/39002: harmful AWK extension: non-portable escaped character

[James Chacon <jmc%netbsd.org@localhost>]

On Jun 20, 2008, at 2:58 PM, Aleksey Cheusov wrote:

> > > I think gawk does right thing here and I'd like to see the same in
> > > NetBSD.
> >
> > Gawk is sometimes a noisy pain in the butt.  :-)
> >
> > It is long standing tradition in Unix tools and languages to ignore
> > the backslash on non-special characters, right from C on up.
> Please, do not repeat this $%^& "nawk is the only true awk...and
> bla-bla-bla".  "Long standing trandition" is bad argument here. Today
> is year 2008 and there is POSIX.
> (I'm not big fun of GNU awk but this doesn't matter)
>
> > I personally don't think AWK should make any noisy warnings like  
> > this.
> If you don't like noise, fix your programs. It's easy ;)
>
> > The fact that mawk does the wrong thing is disturbing, though I'm not
> > sure that justifies making a noisy warning.
> The real problem is not in mawk. The problem is that NetBSD code does
> not conform to POSIX and is not as portable as it is claimed.

Actually it's the script which is non-portable when it  attempts to  
discern any behavior from \X where X isn't specifically defined.

Since you want to quote the standards, look at the table for  
characters not specifically listed and you find for \c:

A backslash character followed by any character not described in this  
table or in the table in the Base Definitions volume of IEEE Std  
1003.1-2001, Chapter 5, File Format Notation ( '\\' , '\a', '\b',  
'\f', '\n', '\r', '\t', '\v').
Meaning: Undefined

i.e. the implementation can pretty much do what it will there. It can  
print error messages, it can treat it as C always has, it can pass it  
through, etc.

James