Re: Puzzling CGI behavior

The quick (and possibly dirty, depending on your POV) is to ensure that your hash has a default value the first-time through.

my %webobj = (
                'template' => param('template')||'',
                'minscale' => param('minscale')||'0'
            );
[download]

A quick test shows this seems to work ok for your example.

Examine what is said, not who speaks.

The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

Comment on Re: Puzzling CGI behavior Download Code

Replies are listed 'Best First'.
Re: Re: Puzzling CGI behavior by punkish (Priest) on Jan 30, 2003 at 03:13 UTC
thanks for the suggestion. I will take it. However, here's my question. Why does this happen? I mean, I can also do something like `my $template = param('template'); my $minscale = param('minscale'); my %webobj = ( 'template' => $template, 'minscale' => $minscale );` [download] and then I get acceptable behavior. But, this shouldn't be necessary. In fact, even if I get something strange, why the heck does 'template' => param('template') end up grabbing 'minscale' as its value... that comma after param('template') should tell it to lay off of 'minscale'. Would love to find out why? Many thanks	[reply] [d/l]
Re: Re: Re: Puzzling CGI behavior by chromatic (Archbishop) on Jan 30, 2003 at 03:27 UTC
that comma after param('template') should tell it to lay off of 'minscale'. It doesn't, though. merlyn has the right of it, as usual. There are no parameters. Calling `param()` in list context (as happens in the hash assignment) produces an empty list in this case. Since there has to be a value, Perl grabs the next one in a list. Your snippet is equivalent to: `my %webobj = ( 'template', param( 'template' ), 'minscale', param( 'minscale' ), );` [download] Consider what happens if you assign an empty list: `use strict; use Data::Dumper; my %hash = ( foo => ,,, bar => 1 => 'baz' ); print Dumper \%hash;` [download]	[reply] [d/l] [select]