define and heredoc

Question

How do you use define within a heredoc? For example:

define('PREFIX', '/holiday');

$body = <<<EOD
<img src="PREFIX/images/hello.png" />   // This doesn't work.
EOD;

score 11 · Accepted Answer · answered Nov 23 '11 at 13:28

11

taken from the documentation regarding strings

DEFINE('PREFIX','/holiday');

$const = PREFIX;

echo <<<EOD
<img src="{$const}/images/hello.png" /> 
EOD;

answered Nov 23 '11 at 13:28

Jan Dragsbaek

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Thanks! Adding a little note: `$const/images/hello.png` will also work. – moey Nov 23 '11 at 13:47
1

curly brackets are not required in this example. – wlf Dec 07 '12 at 14:01
1

Also you can use `$consts = get_defined_constants();` to get all define and then access with `{$consts['PREFIX']}`. – PhoneixS Dec 11 '17 at 11:04

MC_delta_T · Answer 2 · 2014-02-01T09:15:41.083

7

if you have more than 1 constant, variable usage would be difficult. so try this method

define('PREFIX', '/holiday');
define('SUFFIX', '/work');
define('BLABLA', '/lorem');
define('ETC', '/ipsum');

$cname = 'constant'; // if you want to use a function in heredoc, you must save function name in variable

$body = <<<EOD
<img src="{$cname('PREFIX')}/images/hello.png" />
<img src="{$cname('SUFFIX')}/images/hello.png" />
<img src="{$cname('BLABLA')}/images/hello.png" />
<img src="{$cname('ETC')}/images/hello.png" />
EOD;

http://codepad.org/lA8L2wQR

edited Feb 01 '14 at 09:15

answered Sep 20 '12 at 08:40

MC_delta_T

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I followed your suggestion to try that because I thought it is interesting, however it came to my mind that your suggestion looks untested, because it gives many errors. – hakre Sep 24 '12 at 08:06
(Hmm. Crazy. I would've never....) Any thoughts on speed in comparison to @nbonniot answer: http://stackoverflow.com/questions/10041200/interpolate-constant-not-variable-into-heredoc#answer-30777936 – Ricalsin May 06 '16 at 18:15

score 3 · Answer 3 · answered Nov 23 '11 at 13:30

3

Constants used within the heredoc syntax are not interpreted!

Editor's Note: This is true. PHP has no way of recognizing the constant from any other string of characters within the heredoc block.

Source

answered Nov 23 '11 at 13:30

codaddict

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Looks like that there is an exception to that rule: http://stackoverflow.com/a/12508992/367456 – hakre Sep 24 '12 at 08:07

define and heredoc

3 Answers3

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