handful and interval

[Dmitry Olshansky]

On 02-Sep-12 18:22, Andrei Alexandrescu wrote:
 > I'd like to add a simple function to std called "handful". It would
 > return a small, read-only set of which main facility is membership test:
 >
 > string a = "class";
 > if (a in handful("struct", "class", "union"))
 > {
 >      ...
 > }
 >
 > Would it be generally useful, and if so what module does it belong to?
 >
 >
I wouldn't question utility but rather the implementation of the above.
One thing I'd love to see is thing like
handful!("struct", "class", "union")

that does pre-process contents at compile time to speed up search.
In other words it's possible to not only come close to  a series of a == 
"struct" || a == "class" || a == "union" but surpass it.

At the very least handful!(a,b,c) can take expression tuple and make
x in handful!(a,b,c) lower to:
return x == a || x == b || x == c;

even for run-time variables a, b & c.

-- 
Olshansky Dmitry