CODEWITHSUNDEEP
phpconstants
Sohil Desai
Sohil Desai

Reputation: 2988

php constants math operation

Currently i am learning php. Here I have a confusion this is my php code

class OBJECT_ENUM
{
    const USER = 10;
    const POST = 30;
    const SECURE_REQUEST = 40;
}

class OPERATION_ENUM
{
    const INSERT_USER = OBJECT_ENUM::USER + 1; // <- here it gives an error
    const SEND_MAIL = OBJECT_ENUM::USER + 2;

    const LIKE_POST = OBJECT_ENUM::POST + 1;
    const INSERT_POST = OBJECT_ENUM::POST + 2;

    const ENCRYPT = OBJECT_ENUM::SECURE_REQUEST + 1;
}

error message: 
Parse error: syntax error, unexpected '+', expecting ',' or ';' in /var/www/workspace/6thAssignment/include/tempCall.php on line 15

I just don't understand why this error occurs.?? cany anybody explain me.??

Thank you in advance

Upvotes: 2

Views: 1511

Answers (4)

Michael Sivolobov
Michael Sivolobov

Reputation: 13300

ORIGINAL ANSWER:

As you can see in http://www.php.net/manual/en/language.oop5.constants.php:

The value must be a constant expression, not (for example) a variable, a property, a result of a mathematical operation, or a function call.

UPDATED:

From PHP version 5.6 now it is possible to use expressions in constants.

Upvotes: 5

Steve B
Steve B

Reputation: 644

At the moment this is not allowed by PHP. There was an RFC (Request for comments) to get this added to the language:

https://wiki.php.net/rfc/const_scalar_expressions

however this was withdrawn as the author of the RFC has left the internals development team. So I suspect this may not happen any time soon but that's not to say that this won't come back in some form or another at a later date.

Upvotes: 0

H&#233;ctor Pa&#250;l Cervera-Garc&#237;a
H&#233;ctor Pa&#250;l Cervera-Garc&#237;a

Reputation: 618

I believe expressions (like $a + 1) are not allowed in constants definitions, so there is why you are getting that error.

Upvotes: 1

rcs
rcs

Reputation: 7197

I think you can not do mathematical operation to be assigned to a const variable. Try changing 

const INSERT_USER = OBJECT_ENUM::USER + 1;

to

$INSERT_USER = OBJECT_ENUM::USER + 1;

Upvotes: 2

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