Er, er
I've grown fond of the JavaScript || idiom:
function FrobImage(img) {
var width = img.width || 400;
var height = img.height || 300;
// ...
}
FrobImage({height: 100, name: "example.png"});
If img.width exists and it's truthy,
then width = img.width; otherwise, width = 400.
Here, it will be 400 since the img hash
has no width property.
More than two alternatives may be used:
x = a || b || c || ... || q;
A few weeks ago, while cleaning up the error handling in some batch files,
I came across a similar idiom:
foo.exe bar 123 "some stuff" || goto :Error
Only if foo.exe fails (exit() returns a non-zero value),
is the second clause executed.
Perl's die is typically used in a very similar idom:
chdir '/usr/spool/news' || die "Can't cd to spool: $!\n"
though the or keyword seems to be preferred nowadays to ||.
This morning, I came across the ?? operator in C# 2.0,
aka the null coalescing operator:
Customer cust = getCustomer(id) ?? new Customer();
If getCustomer(id) is not null, then that's the value that cust gets;
otherwise it's set to new Customer().
All of these idioms are syntactic sugar and all of them are in my toolbox.
