I just found out that the following (awesome) syntax is accepted by Firefox
f = function(x) x+1;
f(17) //gives 18
Does anyone know what the hell is going on here? Is this in any standard? Do other browsers also accept it? (I tested IE 8 and it gave me syntax error)
This isn't part of a standard. The documentation is at https://developer.mozilla.org/en/New_in_JavaScript_1.8#Expression_closures_%28Merge_into_own_page.2fsection%29
There's discussion about adding some syntax along these lines or even shorter to the standard. See http://wiki.ecmascript.org/doku.php?id=strawman:shorter_function_syntax
The braces are being omitted, just as you can for other control structures that take a block (if,for). It's part of standard syntax for those, perhaps not for functions. One could check the spec I guess.
The convention is that if braces are omitted, the block is the following single statement (only one statement).
For example
if(x) g=1;
is equivalent to
if(x){ g=1; }
However, note that
if(x) g=1; f=2;
is NOT equivalent to
if(x){ g=1; f=2; }
it is actually
if(x){ g=1; } f=2;
I avoid the braceless construct, personally, since it can lead to maintainability problems when the code is modified by people who don't know how this works.
