[ic] incrementing array index in [perl]

[Ryan Grace]

--- Stefan Hornburg <racke@linuxia.de> wrote:
> On Wed, 5 Feb 2003 22:59:38 -0800 (PST)
> Ryan Grace <ryan_grace@yahoo.com> wrote:
> 
> > Hi All,
> > 
> > I've been banging my head on this one for hours
> now
> > and have searched the archives to no avail.  I'm
> > hoping someone knows this one.
> > 
> > I've got a block of perl in a [perl] tag.  I'm
> trying
> > to figure out the current page to show, the next
> page
> > to show, and the previous page to show, all for
> some
> > navigation links furthur down the page.  I'm
> assigning
> > page numbers from the database to scratch
> variables to
> > keep track of the next, current, and previous
> pages.
> > 
> > In the following code, the pagemin and pagemax
> scratch
> > variables are set correctly, so I know the array
> of
> > values form the DB is good.  The viewpage scratch
> > variable is also set correctly.  I've got some
> > [scratch] tags further down the page that show me
> the
> > values they're set to each time.  However, the
> last
> > two variables I can not get right.  I can't get
> the
> > nextpage and prevpage vars to set.  I think it's a
> > problem with the array indexes.  If I set one of
> the
> > scratches like:  $Scratch->{prevpage} = $pages[2];
> it
> > works fine.  But the way it is below does not
> work. 
> > Any ideas?
> > 
> > ---------------------------
> > 
> > [perl tables=products interpolate=1]
> >     my $db = $Db{products};
> > 
> >     $set = $db->query("SELECT page FROM products
> WHERE
> > inactive != 1 AND collec\
> > tion = '[cgi cn]' ORDER BY 1 ASC");
> > 
> >     @pages = ();
> > 
> >     foreach my $row (@$set) {
> >         push (@pages, $$row[0]) if ($$row[0] ne
> "");;
> >     }
> > 
> >     $Scratch->{pagemin} = $pages[0];
> >     $Scratch->{pagemax} = $pages[$#pages];
> > 
> >     if ($CGI->{page}) {
> >         $Scratch->{viewpage} = $CGI->{page};
> >     }
> >     else {
> >         $Scratch->{viewpage} = $pages[0];
> >     }
> > 
> >     my $incr = 0;
> > 
> >     foreach (sort @pages) {
> >         if ($_ = $Scratch->{viewpage}) {
> >             $prev = $Scratch->{incr} - 1;
> >             $next = $Scratch->{incr} + 1;
> >             $Scratch->{nextpage} = $pages[$next];
> >             $Scratch->{prevpage} = $pages[$prev];
> >         }
> > 
> >         $Scratch->{incr}++;
> >     }
> > 
> >     return;
> > [/perl]
> > 
> > Of course I've also tried the more obvious
> > $Scratch->{prevpage} = $pages[$incr-1], which is
> my
> > preferred method, but that doesn't work either.
> 
> Why do you use the sort in the second loop. That
> puzzles me.
> I suppose you can do this all in one loop anyway.
> 
> Bye
> 	Racke

You're right, it's unnecessary.  I've hacked this code
to pieces a number of times trying to fix this and
that sort's left over from an idea that maybe the
pages weren't in the array in order.

Ryan

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