Bob-
This was extremely useful. Thanks for the tips.
Regards,
Jeff
--- Bob Showalter <[EMAIL PROTECTED]> wrote:
> Jeff Westman wrote:
> > I inherited this script, whose code is as follows:
> >
> > #!/usr/local/bin/perl -w
> > ...
> > # 'while' starts on line 42
> > while (($app_key, $app_value) = each %app_file_count) {
> > delete ($app_file_count{$app_key});e
> > }
> >
> > What is the "hanging 'e' on line 43? It is not a subroutine call,
> > and there is no terminating semi-colon (';'). Yet, when I do a
> > syntax check, I get:
> >
> > $ perl -c myscript.pl
> > Unquoted string "e" may clash with future reserved word at my line 44.
> > Useless use of a constant in void context at my line 43. myscript.pl
> > syntax OK
> >
> >
> > I'm confused why this is passing a syntax check. This script runs in
> > production (without the warning flag).
>
> From perldoc 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
> "use warnings" pragma or the -w switch, Perl will warn you
> about any such words. Some people may wish to outlaw
> barewords entirely. If you say
>
> use strict 'subs';
>
> then any bareword that would NOT be interpreted as a sub-
> routine call produces a compile-time error instead. The
> restriction lasts to the end of the enclosing block. An
> inner block may countermand this by saying "no strict
> 'subs'".
>
> So the e is a bareword. Adding 'use strict' is the cure for this. I
> strongly
> suspect the e is just a typo; since it's in a statement by itself, it has
> no
> side effects, so the script has always worked.
>
> From perldoc perlsyn:
>
> Simple statements
>
> The only kind of simple statement is an expression evalu-
> ated for its side effects. Every simple statement must be
> terminated with a semicolon, unless it is the final state-
> ment in a block, in which case the semicolon is optional.
>
> So no syntax error about a missing semicolon, because it's the last
> statement in the block.
>
> Also, for fun, try running this portion of the script through:
>
> perl -c -MO=Deparse myscript.pl
>
> You'll see the following:
>
> while (($app_key, $app_value) = each %app_file_count) {
> delete $app_file_count{$app_key};
> '???';
> }
>
> The literal in void context into '???' to show you that it's a useless
> statement. (From perldoc B::Deparse, '???' indicates a constant that has
> been optimized away).
>
>
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