Re: [FWP] Problem - rewrite and simplify

[John Carter <john@dwaf-hri.pwv.gov.za>]

On 1 Jul 1999, Chaim Frenkel wrote:
> >>>>> "JC" == John Carter <john@dwaf-hri.pwv.gov.za> writes:
> JC> On Wed, 30 Jun 1999, Edward M. Perry wrote:
> >> Just for fun, I like:
> >> 
> >> while(<CLONEIDSLIST>) { push(@ids, eval); }
> 
> JC> Yes, its fun, it works, and for the grand prize please explain :-
> JC>   a) Why does it work?
> JC>   b) How the blue blazing bliksem's did you find out that it would?
> 
> Think list context, bearwords, and -w.

Well I be damned, it _is_ documented. In many odd corners, but it
_is_ actually documented...

>From "man perldata"

       A word that has no other interpretation in the grammar
       will be treated as if it were a quoted string.  These are
       known as "barewords".  As with filehandles and labels, a
       bareword that consists entirely of lowercase letters risks
       conflict with future reserved words, and if you use the -w
       switch, Perl will warn you about any such words.  Some
       people may wish to outlaw barewords entirely.

I would heartily second that last sentence!

>From "man perlop" on the comma operator...

      In a list context, it's just the list argument separator,
      and inserts both its arguments into the list.

Eval working on $_ is standard behaviour for nearly all things in "man
perlfunc", so no suprise there.


> But I can't get it to work. @ids ends up empty.

That's strange, running the following on perl, version 5.004_04 built
for i386-linux works fine...

perl -we 'while(<STDIN>) { push(@ids, eval);}print join(":",@ids),"\n";'
a,b,c,d
Unquoted string "a" may clash with future reserved word at (eval 1) line 1, <STDIN> chunk 1.
Unquoted string "b" may clash with future reserved word at (eval 1) line 1, <STDIN> chunk 1.
Unquoted string "c" may clash with future reserved word at (eval 1) line 1, <STDIN> chunk 1.
Unquoted string "d" may clash with future reserved word at (eval 1)
line 1, <STDIN> chunk 1.
<cntrl-d>
a:b:c:d



John Carter                    EMail: ece@dwaf-hri.pwv.gov.za
Telephone : 27-12-808-0374x194 Fax:- 27-12-808-0338
<http://www.geocities.com/SoHo/Cafe/5947> or <http://iwqs.pwv.gov.za>

Despite all cheerful predictions, I'm moving seamlessly from being a
confused and angry young man to becoming an angry and confused old
man.


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