[pmwiki-users] Hg tweaks...

[Patrick R. Michaud]

On Fri, Feb 02, 2007 at 09:03:15PM +0000, Américo Albuquerque wrote:
> Kathryn Andersen wrote:
> > Oh, I've also run into something puzzling, a line which I changed...
> >    $FmtPV["$$hg"] = "'" . $gg . "'";
> > Wouldn't that work better as the following?
> >    $FmtPV['$' . $hg] = "'" . $gg . "'";
> > 
> > I'm not sure that the $$ will give what is needed.  Or maybe I'm just
> > being paranoid.
> > 
> Those sentences do different things. When you use ["$$hg"] you are 
> saying to use the '$' character before the hg'. That is the same as 
> writing ['$hg'] (note the single quotes).  [...]
> Basically, the $$ inside double quotes is changed into a single $

Nope.  "$$hg" is the same as '$' . $hg .  

Here's a test script (also at http://www.pmichaud.com/sandbox/hg.php):

    <?php
    $hg = 'xyz';
 
    header("Content-type: text/plain");
 
    echo "$$hg",        "\n";
    echo '$' . $hg,     "\n";


It outputs the following, showing that they are equivalent.

    $xyz
    $xyz

Note that this is different from using $$hg outside of quotes,
which treats $hg as being the name of a variable to look up.
Thus:

    $hg = 'xyz';
    $xyz = 'abc';

    echo $$hg;     # outputs 'abc';

Pm