[Nickle]Boolean type, twixt, static vs global, built-in profiling

[Keith Packard]

Around 10 o'clock on Jul 30, Carl Worth wrote:

> Looking at the split function you wrote for compose. Do we want some
> builtin support for array manipulation? It could be a function similar
> to your split, (although I'd vote for "slice"). Or the array index
> could accept an array of values. That, along with some support for
> easily constructing arrays of integers could be quite handy.

I think comprehensions would give us relatively clean syntax without any 
artificial limitations on what kinds of subsetting could be done.  A
comprehension is essentially a lambda evaluated for each element of an 
array during initialization:

	(int[3]) { comprehension (int i) { return i * 2; } }

We can either use these as immediate values or build simple array
manipulation functions from them.

-keith