On Wed, Jul 6, 2011 at 12:07 PM, Dave Wilson <dai_bach24@xxxxxxxxxxx> wrote:
> Hi all,
>
> OK. We all know that constants cannot be accessed directly via their name
> in double-quoted or heredoc strings. I knew this already but a read of
> the PHP manual got me thinking.
>
> The manual states that to get the $$ value of a variable, the form
> "{${var}}" should be used. Therefore, I wondered if something similar
> would work for constants.
>
> Attempt 1 (just to be sure):
> <?php
> define ('XYZ','ABC');
> echo "{XYZ}\n";
> ?>
>
> Output - {XYZ}
>
> Attempt 2:
> <?php
> define ('XYZ','ABC');
> echo "{{XYZ}}\n";
> ?>
>
> Output - {{XYZ}}
>
> No luck there. I did encounter one oddity though:
>
> <?php
> define ('XYZ','ABC');
> echo "{${XYZ}}\n";
> ?>
>
> Output:
> PHP Notice: Undefined variable: ABC in /home/wilsond/testScripts/l7.php
> on line 3
>
> Which appears to mean that PHP is able to pick up the value of the
> constant and try to access a variable with that name.
>
> Any ideas?
>
My guess is that the preceding $ causes PHP to interpret the next token
"{XYZ}" as a variable or a constant, but without that preceding $ it has no
way to know you're trying to use a constant. As Curtis points out, the only
way to insert a constant into a string is through concatenation.
-Stuart
--
Stuart Dallas
3ft9 Ltd
http://3ft9.com/
