Re: Does gawk manual mention how an empty regex should be handled?

[Arkadiusz Drabczyk]

On Wed, Mar 31, 2021 at 10:34:24AM -0600, arnold@skeeve.com wrote:
> Hi.
> 
> Arkadiusz Drabczyk <arkadiusz@drabczyk.org> wrote:
> 
> > TIL that empty regex matches any string:
> 
> Not sure what "TIL" is.

It means Today I Learned (sorry, I thought it's commonly known)

> > $ awk 'BEGIN { print "abc" ~ "" }'
> > 1
> > $ awk 'BEGIN { print "abc" ~ // }'
> > 1
> >
> > It can also be reproduced with mawk, Busybox awk and FreeBSD
> > awk. However, I wasn't able to find an explanation of that behavior in
> > the gawk manual.
> 
> The match is to the empty string before and after each character.
> You can see this with gsub():
> 
> $ gawk 'BEGIN { x = "ABC"
> > gsub(//, "x", x) ; print x }'
> xAxBxCx
> 
> > Is it actually documented somewhere?
> 
> I thought it was, but it may not be. I can't find it at the moment,
> but I will take a harder look later.

ok, thank you.

-- 
Arkadiusz Drabczyk <arkadiusz@drabczyk.org>