Edit report at https://bugs.php.net/bug.php?id=63156&edit=1
ID: 63156
User updated by: herb at bobbingwide dot com
Reported by: herb at bobbingwide dot com
Summary: using if ( expression ) requires functions to be
declared before calls
Status: Duplicate
Type: Bug
Package: *Programming Data Structures
Operating System: Windows XP
PHP Version: 5.3.17
Block user comment: N
Private report: N
New Comment:
I accept that this is a duplicate of #17055.
And since derick said, in response to #17055, "I don't see any fast
implementation of this.", 10 years ago (May 2002), I'm inclined to agree that
this will have to be dealt with as a documentation problem.
However, in my particular scenario the original response to the problem... "The
only way to prevent this is to move out the function declaration out of the
branch and in the main scope of the script." is not acceptable since the whole
point of the encapsulating code was to prevent the functions from being
multiply
defined.
So I believe the documentation should provide a clear explanation of the
parsing
and interpretation processes involved.
Previous Comments:
------------------------------------------------------------------------
[2012-09-25 09:46:26] [email protected]
dup to #17055
------------------------------------------------------------------------
[2012-09-25 05:13:48] [email protected]
Top level declaration are available after compiling, but conditional declaration
can only be available after executed. (since PHP itself didn't do optimization,
i`f(true) {doSomething();}` is not equal to `doSomething();` exactly )
the same rules for class declarations.
This could be classified as a documentation problem.
------------------------------------------------------------------------
[2012-09-25 02:40:07] [email protected]
it is good manner always declare function/class before using it.
------------------------------------------------------------------------
[2012-09-24 19:56:55] herb at bobbingwide dot com
Description:
------------
When enclosing code between if ( expression ) { and } it appears that versions
of PHP up to and including 5.3.17 require functions to be declared before they
are used. I first noticed the problem when I tried to wrap a whole PHP source
file like this
<?php
if ( !defined( 'CONSTANT' )) {
define( 'CONSTANT', true );
// whole file here
} // end defined
I reduced the problem to the simplest; replacing !defined( 'CONSTANT') with
true
and got the same unexpected results. The code did not work unless the (top
level) functions were declared before they were used.
I found the problem on PHP 5.3.5 where the code produced a Fatal error: Call to
undefined function. I have since reproduced the Fatal error on PHP 5.3.16 and
5.3.17
If you remove the 'if test' (lines 2 and 7) the code works fine.
If you put the call to the function after the declaration that also works.
This code, where the call to b() is before the declaration of function b, also
works
<?php
if ( true ) {
function a() {
echo "a" . PHP_EOL;
b();
}
function b() {
echo "b" . PHP_EOL;
}
a();
}
producing
a
b
Test script:
---------------
<?php
if ( true ) {
a();
function a() {
echo "a" . PHP_EOL;
}
}
Expected result:
----------------
a
Actual result:
--------------
Fatal error: Call to undefined function a() in C:\apache\htdocs\wordpress\wp-con
tent\plugins\play\defined.php on line 3
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=63156&edit=1
