Re: [MacPerl] help

[Bruce Van Allen <bva@cruzio.com>]

At 3:17 PM 11/18/00, Amitava Basu wrote:
>Hello:
>
>I have typed in the following script from Learning Perl. I
>discarded the flock
>function since it is not implemented in MacPerl.  When I run
>the script it
>shows following error:
>
><HR><FORM METHOD="POST"
>ENCTYPE="application/x-www-form-urlencoded">
></HR># Can't call method "textfield" without a package or
>object reference, <> chunk 1.
>File '.LC 1:Desktop Folder:scripts:guest.pl'; Line 31
>
>I am unable to understand the problem. Can someone out there
>please guide me.

In the script you've shown, you are using several subroutines from 
the CGI.pm module that provide HTML markup in your output. Among 
others, these include p, h1, h2, hr, start_form, end_form, and 
end_html. You also use some CGI.pm subroutines to access data 
returned to your script (param), and some others.

In some cases (e.g., "print hr start_form;") the script uses these 
subs 'bare' because they are imported via the ':standard' invocation 
in your statement "use CGI qw (:standard);"

In other cases (e.g., "$entry->param("message");"), your script uses 
CGI subs qualified with the object reference "entry->", specific to 
each of your @entries items, each one created in the loop

   while (!eof (CHANDLE) && $#entries < $MAXSAVE) {
     $entry = CGI->new(\*CHANDLE);
     push @entries, $entry;
   }

But the phrase that has caused the error
   $cur->textfield ( ...
doesn't work because your script hasn't created the CGI object $cur 
anywhere. All your script has done is initialize the scalar variable 
$entry, which holds each object reference during each iteration 
through the loops its in.

Try writing using textfield() without the $cur->.

But there are other problems here as well. Lose the spaces around the 
arrows, for one.

Incidentally, if you are new to Perl/MacPerl, I'd suggest that this 
isn't the simplest approach for learning, because you are dealing not 
only with Perl's functions and structures, but also with CGI.pm's own 
functions/subroutines and its approach to writing HTML. Plus, you 
happen to have chosen an example that has several layers of Perl, 
such as references and objects, that are difficult to make sense of 
until you've gotten control over the more basic stuff.

Of course one way to learn a language is to obsess over something 
that you really want to get working. If you continue with this 
example, though, I'd suggest studying the author's excellent 
documentation of CGI.pm (book: Official Guide to Programming with 
CGI.pm, by Lincoln Stein, Wiley, 1998; or online: 
http://www.wiley.com/compbooks/stein/).

HTH

1;


- Bruce

__Bruce_Van_Allen___Santa_Cruz_CA__

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