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Clarify the text about remaining PHP constant oddity.

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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12752 626c5289-ae23-0410-ae9c-e8d60b6d4f22
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Olly Betts 2011-06-25 12:48:08 +00:00
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Doc/Manual/Php.html
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@ -180,9 +180,8 @@ other symbols unless care is taken to <tt>%rename</tt> them.
<H3><a name="Php_nn2_1"></a>31.2.1 Constants</H3> <H3><a name="Php_nn2_1"></a>31.2.1 Constants</H3>
<p> <p>
These work in much the same way as in C/C++, constants can be defined These work in much the same way as in C/C++. Constants can be defined
by using either the normal C pre-processor declarations, or the by using either the normal C pre-processor declarations, or the
<tt>%constant</tt> SWIG directive. These will then be available from <tt>%constant</tt> SWIG directive. These will then be available from
your PHP script as a PHP constant, (i.e. no dollar sign is needed to your PHP script as a PHP constant, (i.e. no dollar sign is needed to
@ -199,7 +198,7 @@ access them.) For example, with a swig interface file like this,
</div> </div>
<p> <p>
you can access the constants in your php script like this, you can access the constants in your PHP script like this,
</p> </p>
<div class="code"><pre> <div class="code"><pre>
@ -213,9 +212,16 @@ echo "E = " . E . "\n";
</div> </div>
<p> <p>
There are two peculiarities with using constants in PHP. The first is that There's one peculiarity of how constants work in PHP which it is useful
if you try to use an undeclared constant, it will evaluate to a string to note (this is not specific to SWIG though) - if you try to use an undeclared
set to the constant's name. For example, constant, PHP will issue a warning and then expand the constant to a string
version of the constant's name. The warning will often be missed though as
if you're using PHP in a webserver, it will probably end up in error.log or
similar.
</p>
<p>
For example,
</p> </p>
<div class="code"><pre> <div class="code"><pre>
@ -243,10 +249,9 @@ if(EASY_TO_MISPEL) {
</div> </div>
<p> <p>
will issue a warning about the undeclared constant, but will then The mis-spelled constant will become the string 'EASY_TO_MISPEL', which
evaluate it and turn it into a string ('EASY_TO_MISPEL'), which is treated as true by the if test, when the value of the intended constant
evaluates to true, rather than the value of the constant which would would be treated as false!
be false. This is a feature!
</p> </p>
<H3><a name="Php_nn2_2"></a>31.2.2 Global Variables</H3> <H3><a name="Php_nn2_2"></a>31.2.2 Global Variables</H3>