CTFE Status

[Stefan Koch via Digitalmars-d]

On Thursday, 15 December 2016 at 23:37:50 UTC, Stefan Koch wrote:
> On Thursday, 15 December 2016 at 23:05:55 UTC, Dmitry Olshansky 
> wrote:
>>
>> Afaik string switches are implemented as a fairly slow hash 
>> table. Optimal solutions like building a trie would be a nice 
>> enhancement.
>>
>> ---
>> Dmitry Olshansky
>
> Tries take up alot of memory for sparse tables.
> I would like to avoid them.
>
> Futhermore, CTFE is targeted towards smaller functions with low 
> iteration count.
> Therefore producing bytecode as fast as possible is priority.
>
> This function from std.uri does now compile and execute 
> correctly.
> private enum
> {
>     URI_Alpha = 1,
>     URI_Reserved = 2,
>     URI_Mark = 4,
>     URI_Digit = 8,
>     URI_Hash = 0x10,        // '#'
> }
>
> immutable ubyte[128] uri_flags =      // indexed by character
>     ({
>         ubyte[128] uflags;
>
>         // Compile time initialize
>         uflags['#'] |= URI_Hash;
>
>         foreach (c; 'A' .. 'Z' + 1)
>         {
>             uflags[c] |= URI_Alpha;
>             uflags[c + 0x20] |= URI_Alpha;   // lowercase 
> letters
>         }
>         foreach (c; '0' .. '9' + 1) uflags[c] |= URI_Digit;
>         foreach (c; ";/?:@&=+$,")   uflags[c] |= URI_Reserved;
>         foreach (c; "-_.!~*'()")    uflags[c] |= URI_Mark;
>         return uflags;
> })();
>
> I have to say I was surprised myself :)
> It takes around 30 us to execute, which can be improved for 
> sure :)

Hey Guys, I just had a mental breakthrough in regards to handling 
doubly in-directed read-modify-write operations.
such as changing the length of an array through a pointer.
Refernce values will carry a typed pointer to their origin 
thereby allowing them to be treated like normal values most of 
the time, and only receive special treatment on assignment.
(Which is where they have to emit a Store32 Instead of a Set)
As this has design implications, I will resolve this  before 
continuing function-call support.
In fact, I think I will have to delay call support until most of 
the ABI issues are worked out.