Using php 5.5.38.
Simple script:
<?php
function a ($a = 'XXX' . 'TTT') {
echo 'Hello ' . $a;
}
a();
This fails with:
PHP Parse error: syntax error, unexpected '.', expecting ')' in line 3
Does php 5.5 not support concatenation in there?
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3You can't have expressions inside the function default parameters, only primitive values.Phiter– Phiter2018-10-30 14:24:01 +00:00Commented Oct 30, 2018 at 14:24
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@Phiter You mean at all or just in php 5.5?DonJoe– DonJoe2018-10-30 14:24:29 +00:00Commented Oct 30, 2018 at 14:24
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I believe just in 5.5. Look secure.php.net/manual/en/…Phiter– Phiter2018-10-30 14:25:42 +00:00Commented Oct 30, 2018 at 14:25
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It works on 7.1 ideone.com/zdpGokPhiter– Phiter2018-10-30 14:26:40 +00:00Commented Oct 30, 2018 at 14:26
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1It was added in PHP 5.6 - see the section at the top of the changelog labelled Constant Expressionsiainn– iainn2018-10-30 14:27:18 +00:00Commented Oct 30, 2018 at 14:27
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3 Answers
This feature was added in PHP 5.6. The same rule applies to class propety declarations.
It is now possible to provide a scalar expression involving numeric and string literals and/or constants in contexts where PHP previously expected a static value, such as constant and property declarations and default function arguments.
See: Constant expressions
Comments
It seams like in PHP 7 you can use string concatenation in the function argument defaults, but it doesn't make any sence.
Comments
no php 5.5.38. does not support this method. You need a php version that is >= 5.6.0
Good luck
