PHP EMPTY token

define('EMPTY', '');
if(!empty(EMPTY))
{
if(!(boolean) _CONSTANT)
{
    print "One";
}
}

The above code produces the following error message:

"Parse error: syntax error, unexpected 'EMPTY' (T_EMPTY) in C:UsersRobertDocumentsweb developmentxampphtdocsxamppweb_developmentindex.php on line 3"

Nowhere in the PHP Manual does it explicitly state that "EMPTY" is a token nor does it inform you about this pitfall.

---

函数名称不区分大小写。

$state = constant('EMPTY');
if (!empty($state)) {

---

You can declare constants with the same name as functions as PHP uses () to determine if a token is a function or constant declaration:

<?php
function myfunc() {
 echo "inside myfunc()n";
}
define('str_replace', 'my string');
echo str_replace . "n";
echo str_replace("A", "B", "AAAA") . "n";
define('myfunc', 'this is myfunc constant');
echo myfunc . "n";
myfunc();

/*
Output:
my string
BBBB
this is myfunc constant
inside myfunc()
 */

This doesn't work for empty because empty is a language construct.

---

This isn't a problem... just pick another name for your constant.

If you would like, you can submit a documentation bug report.

链接地址: http://www.djcxy.com/p/59448.html

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