[PHP] dollar sign ($) 的陷阱

// == case 1 ==
$foo = 'foo';$
$bar = 'bar';
// expect: $foo = 'foo', $bar = 'bar'
// actual: $foo = 'foo', $bar = NULL
// hint:   PHP Notice: undefined variable: bar in test.php on line 4

// == case 2 ==
$foo = 'foo';$
bar  = 'bar';
// actual: PHP Parse error:  syntax error, unexpected T_STRING, expecting T_VARIABLE or '$' in test.php on line 3

// == case 3 ==
$foo = 'foo';$
// actual: PHP Parse error:  syntax error, unexpected $end, expecting T_VARIABLE or '$' in test.php on line 2

可以發現，在一些特定情形下，PHP 允許換行使用錢號 ($)，但是不容易發現。 所以任何 PHP 的訊息應該都要注意。

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