Doc #77100 [Asn->Csd]: Inconsistent behavior between constants and magic constants
| From: | cmb@php.net | Date: | Mon, 05 Nov 2018 14:57:19 +0000 |
| Subject: | Doc #77100 [Asn->Csd]: Inconsistent behavior between constants and magic constants | ||
| References: | 1 | Groups: | php.doc.bugs |
| Request: | Send a blank email to doc-bugs+get-16122@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=77100&edit=1
ID: 77100
Updated by: cmb@php.net
Reported by: fabien dot villepinte at gmail dot com
Summary: Inconsistent behavior between constants and magic
constants
-Status: Assigned
+Status: Closed
Type: Documentation Problem
Package: Scripting Engine problem
PHP Version: Irrelevant
Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
This bug has been fixed in the documentation's XML sources. Since the
online and downloadable versions of the documentation need some time
to get updated, we would like to ask you to be a bit patient.
Thank you for the report, and for helping us make our documentation better.
Previous Comments:
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[2018-11-05 14:56:42] cmb@php.net
Automatic comment from SVN on behalf of cmb
Revision: http://svn.php.net/viewvc/?view=revision&revision=345954
Log: Fix #77100: Inconsistent behavior between constants and magic constants
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[2018-11-05 00:11:59] a at b dot c dot de
That is consistent with variable names: just as you can create a variable that has a name impossible
to use as a literal (e.g., ${"$"}) so too you can create a constant that can't be
referred to literally.
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[2018-11-04 14:58:11] cmb@php.net
@nikic Thanks! Changing to doc problem.
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[2018-11-04 12:44:05] nikic@php.net
I'm inclined to mark this won't fix. Magic constants are just keywords that have
syntactical similarity to constants. I don't think we have any business checking that constant
names do not match keywords. If we forbid define('__DIR__'), should we also forbid
define('function')?
Ultimately everything here works just fine in the sense that you can define that constant and also
look it up using constant(). You can't access it with constant syntax because the __DIR__
keyword takes precedence, but there's any number of other reasons why such an access may not be
possible. For example, you can also do define('123', 'foo') and then access it
using constant('123'), but for obvious reasons it will not change the behavior of directly
writing 123 in code.
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[2018-11-04 11:21:23] cmb@php.net
> I'd suggest prepopulating the constants table with them only I
> don't know how something like constant('__LINE__') could work.
Prepopulating the constants table would require to update it
frequently during run time to be consistent with the compile time
constants. Besides being inefficient, it would also change
âconstantâ values. It might be preferable to not allow any of the
predefined magic constants (or maybe all constant names with two
leading and trailing underscores) to be used with define(),
defined() and constant(). Either way would break BC, though.
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