if ($tx) This code will evaluate to false for any of the following conditions: unset($tx); // not set, will also produce E_WARNING $tx = null; $tx = 0; $tx = ‘0’; $tx = false; $tx = array(); The code below will only evaluate to false under the following conditions: if (isset($tx)) // False under following … Read more
I find the above typo in my code quite a lot. I’m always suprised that the compiler doesn’t seem to care about this. Why is the above not a syntax errror? Because the people designing the C# syntax grammar were smart enough to learn the lessons from other programming languages which didn’t allow the dangling … Read more
It is an unusual idiom, it causes a little pause when you’re reading it, a moment of “huh?”. It works, but most people would probably expect to find the default case at the end: switch($kind) { case ‘kind2’: // do some stuff for kind2 here break; // […] case ‘kindn’: // do some stuff for … Read more
As others have mentioned, Annex D of ISO/IEC 9899:2011 lists the hexadecimal values of characters valid for universal character names in C11. (I won’t bother repeating it here.) I have been searching for an answer as to “why” this list was chosen. Character set standards First, there are two relevant standards defining a set of … Read more
It was certainly not the case at the time of your question, but right now :: is a valid ES7 operator. It’s actually a shortcut for bind. ::foo.bar is equivalent to foo.bar.bind(foo) See an explanation here for examples:
Quick answer: ^[\w*]$ will match a string consisting of a single character, where that character is alphanumeric (letters, numbers) an underscore (_) or an asterisk (*). Details: The “\w” means “any word character” which usually means alphanumeric (letters, numbers, regardless of case) plus underscore (_) The “^” “anchors” to the beginning of a string, and … Read more
The http: is a Label Statement. See here also. The //www.google.com portion is then interpreted as a // comment.
Try digit separator: int i = 1’000’000’000; This feature is introduced since C++14. It uses single quote (‘) as digit separator. Also see: Why was the space character not chosen for C++14 digit separators? Generalizing Overloading for C++2000 (April’s joke by the father of C++ himself)
ANY (or its synonym SOME) is a syntax sugar for EXISTS with a simple correlation: SELECT * FROM mytable WHERE x <= ANY ( SELECT y FROM othertable ) is the same as: SELECT * FROM mytable m WHERE EXISTS ( SELECT NULL FROM othertable o WHERE m.x <= o.y ) With the equality condition … Read more