Nobody screamed (or even whimpered) so patch committed. Thanks for point
out the bug, Eric.
-R
At Sat, 19 Jul 2003 23:12:51 -0700,
Robert Spier wrote:
>
>
> Eric is correct, the FAQ is wrong.
>
> The simplest patch is probably:
>
> --- perlfaq7.pod 31 Jan 2003 17:38:14 -0000 1.14
> +++ perlfaq7.pod 20 Jul 2003 06:09:30 -0000
> @@ -809,5 +809,5 @@
> use your own hash or a real reference instead.
>
> - $fred = 23;
> + $USER_VARS{"fred"} = 23;
> $varname = "fred";
> $USER_VARS{$varname}++; # not $$varname++
>
>
>
>
>
> === Forwarded Message:
>
> Date: Fri, 11 Jul 2003 09:40:56 -0500
> From: Eric Pement <[EMAIL PROTECTED]>
> Subject: Error in Sect. 7 on using a variable as a variable name
> To: [EMAIL PROTECTED]
>
> To whom it may concern:
>
> In trying to learn about references, I believe I've found an error in
> the Perl FAQ, section 7 ("General Perl Language Issues"), under the
> question, "How can I use a variable as a variable name?" The problem
> exists in the documentation for Perl 5.6 and Perl 5.8. I tried
> emailing this message to "[EMAIL PROTECTED]" and got
> no response. Now that I've got a newer email address, perhaps I can
> get a reply.
>
> The FAQ currently reads in part:
>
> By using symbolic references, you are just using the package's
> symbol-table hash (like %main::) instead of a user-defined hash.
> The solution is to use your own hash or a real reference instead.
>
> $fred = 23;
> $varname = "fred";
> $USER_VARS{$varname}++; # not $$varname++
>
> This solution does not work and does not provide "24" as the FAQ
> authors seem to have intended. This can be demonstrated like so:
>
> #!/usr/bin/perl
> use strict;
> my ($fred, $varname, %USER_VARS);
> $fred = 23;
> $varname = "fred";
> $USER_VARS{$varname}++;
> print "Value is: $USER_VARS{$varname}\n";
>
> The output is "Value is: 1". So how should this be corrected? Here's
> a replacement I suggest for the FAQ. It returns "24", as expected:
>
> $USER_VARS{fred} = 23;
> $varname = "fred";
> $USER_VARS{$varname}++; # not $$varname++
>
> Finally, the FAQ says another solution is to use a real reference
> instead. Perhaps you could tell new perl users how this is done:
>
> $fred = 23;
> $varname = \$fred;
> $$varname++;
>
> Thanks in advance for your time.
>
>
> --
> Eric Pement - [EMAIL PROTECTED]
> Education Technical Services, MBI
>
> === End of Forwarded Message
