[phobos] A few minor features

[Walter Bright]

David Simcha wrote:
>
> The functionality is:
>
> 1.  Static array literals that are guaranteed to avoid heap allocations:
>
> /**
> Creates a static array literal, avoiding the heap allocation that results
> from a regular array literal.
> */
> CommonType!(T)[T.length] staticArray(T...)(T elems)
> if(is(CommonType!(T))) {
>     typeof(return) ret = void;
>     foreach(i, Unused; T) {
>         ret[i] = elems[i];
>     }
>
>     return ret;
> }

I'd prefer fixing that in the compiler, I just haven't gotten around to 
it yet.

>
> 2.  A function that allows the address of a nested function to be 
> taken w/o a heap allocation.
>
> /**
> Allows the address of a nested function to be (unsafely) taken without
> resulting in a heap allocation.
> */
> T scopeAddress(T)(scope T val) {
>     return val;
> }
>
> Usage:
>
> void fun() {
>      void nested() {}
>
>     auto addr = scopeAddress(&nested);
> }
>
> 3.  An alwaysAssert() function that stays on in release mode but is 
> otherwise equivalent to assert().  I had been using enforce() for 
> this, but I don't like that anymore because it throws Exception, not 
> AssertError by default.  This means that if I write catch(Exception), 
> I could accidentally be catching what is effectively an assertion 
> failure.  Since assert() is supposed to be terse to encourage the 
> programmer to use it liberally, explicitly passing AssertError to 
> enforce() doesn't cut it.  Mostly what I need here is a better/terser 
> name than alwaysAssert().  Given the nature of this feature, I'd say 
> terseness actually beats explicitness.  The best I've come up w/ so 
> far is rassert() for release assert.
>

So far, what I use for this is:

    if (!condition) assert(0);

Even in release mode, assert(0) will execute a HLT instruction.