buggy awk regex handling?

[RW]

On Thu, 02 Aug 2012 13:20:52 +0200
kaltheat wrote:

> 
> 
> Hi,
> 
> I tried to replace three letters with three letters by awk using the
> sub-routine. I assumed that my regular expression does mean the
> following:
> 
> match if three letters of any letter of alphabet occurs anywhere in
> input
> 
> $ echo AbC | awk '{sub(/[[:alpha:]]{3}/,"cBa"); print;}'
> AbC
> 
> As you can see the result was unexpected.
> When I try doing it for at least one letter, it works:
> 
> $ echo AbC | awk '{sub(/[[:alpha:]]+/,"cBa"); print;}'
> cBa
> ...
> What am I doing wrong?
> Or is awk buggy?

Traditional awk implementations don't support {n}, but I think POSIX
implementations should.