Re: [RFC] Default constructors

> On 20 Nov 2014, at 09:34, Rowan Collins <rowan.collins@gmail.com> wrote: > > Note that there are many, many places where expressions are actioned for their side effects > even though the result is discarded. The following will increment $a 3 times, even though it is > discarded each time: > > $a = 0; > ++$a; // 1 > class Foo { function __construct() {} } > new Foo(++$a); // 2 > function bar() {} > bar(++$a); // 3 > class WTF {} > new WTF(++$a); // suddenly, PHP becomes lazy > > Test: http://3v4l.org/tcnv63 (note that HHVM increments all 4 > times; PHP 4 only twice because class Foo has no old-style constructor) > > Lazy evaluation certainly has benefits, but it's not, in general, a feature of PHP. That > it happens in this one very specific case is what is so unexpected. You’re forgetting perhaps the most common and fundamental case in PHP (and C, from which it comes): expression statements. Any expression, followed by a semicolon, is a valid statement. The expression’s result is discarded, but it’s always evaluated. Otherwise function calls wouldn’t work, nor would assignment, both of which are expression statements. -- Andrea Faulds http://ajf.me/