Question

在线等 高手帮忙 关于PHP的问题

请用一个例子解释，PHP如何动态的建立一个function。
explain with the help of an example, how can a function be dynamically created in PHP?

如果是英文答案就更好了

Answer 1

PHP supports the concept of variable functions. This means that if a variable name has parentheses appended to it, PHP will look for a function with the same name as whatever the variable evaluates to, and will attempt to execute it. Among other things, this can be used to implement callbacks, function tables, and so forth.

Variable functions won't work with language constructs such as echo(), print(), unset(), isset(), empty(), include(), require() and the like. Utilize wrapper functions to make use of any of these constructs as variable functions.

Example #1 Variable function example

<?php
function foo() {
echo "In foo()<br />\n";
}

function bar($arg = '')
{
echo "In bar(); argument was '$arg'.<br />\n";
}

// This is a wrapper function around echo
function echoit($string)
{
echo $string;
}

$func = 'foo';
$func(); // This calls foo()

$func = 'bar';
$func('test'); // This calls bar()

$func = 'echoit';
$func('test'); // This calls echoit()
?>

You can create a function also,and do it as follow:
Creates an anonymous function from the parameters passed, and returns a unique name for it.

<?php
$newfunc = create_function('$a,$b', 'return "ln($a) + ln($b) = " . log($a * $b);');
echo "New anonymous function: $newfunc\n";
echo $newfunc(2, M_E) . "\n";
// outputs
// New anonymous function: lambda_1
// ln(2) + ln(2.718281828459) = 1.6931471805599
?>

Any questions are welcomed to me.

Answer 2

小鬼回答正确，小鬼的站内论坛就是PHP写的，也很棒，只是想给小鬼提个问题，你的论坛自带的博客系统似乎有点问题吧？
评论似乎不能显示，（或者是要在后台设置显示的吗？）评论部分有些编码似乎也失控了吧？