Re: Separating rules with semicolons

On 2/18/2008 6:54 AM, Spiros Bousbouras wrote:
> On page 22 of "Effective AWK programming" we read:
> 
>        When awk statements within one rule are
>        short, you might want to put more than one
>        of them on a line. This is accomplished by
>        separating the statements with a semicolon
>        (`;').  This also applies to the rules
>        themselves. Thus, the program shown at the
>        start of this section could also be written
>        this way:
>       /12/ { print $0 } ; /21/ { print $0 }
>        NOTE: The requirement that states that rules
>        on the same line must be separated with a
>        semicolon was not in the original awk language;
>        it was added for consistency with the treatment
>        of statements within an action.
> 
> But when I try
> gawk --posix  '/a/ {print "swds"} /b/ {print "1234"}'
> it works fine. Same if I omit "--posix". If it is a
> requirement then why does omitting semicolons work ?

It's not required, I don't know why the book claims it is. I suspect it's
just
bad wording and a bad example. It's only required when you need to
explicitly
mark the end of a condition/action/rule upon removing a newline, e.g. to
change
this:

/l2/
{ print $0 }

to one line would need to be:

/l2/ ; { print $0 }

rether than the completely different program:

/l2/ { print $0 }

Regards,

	Ed.