• Yuxuan Shui (5/5) Dec 23 2016 I tried this:
• Yuxuan Shui (3/9) Dec 23 2016 This example here: https://dlang.org/spec/hash-map.html, doesn't
• Nicholas Wilson (3/16) Dec 23 2016 Is this at global scope?
• Stefan Koch (3/9) Dec 24 2016 You cannot initialize an AA at compile-time.
• Carl Vogel (7/9) Dec 24 2016 This bit me when I was first starting out as well. I feel like
• Stefan Koch (5/7) Dec 25 2016 I do intend to fix this.
• Era Scarecrow (11/16) Dec 24 2016 For fun I'm throwing together a quick AA struct that you can
• Stefan Koch (5/25) Dec 25 2016 There are library solutions for AA like containers that can be
• Jack Applegame (10/16) Dec 25 2016 This works:

Yuxuan Shui <yshuiv7 gmail.com> writes:

I tried this:

     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 'P':4];

And got a "non-constant expression" error (with or without 
'immutable').

What's the correct way?

Yuxuan Shui <yshuiv7 gmail.com> writes:

On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui wrote:
 I tried this:

     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 
 'P':4];

 And got a "non-constant expression" error (with or without 
 'immutable').

 What's the correct way?

This example here: https://dlang.org/spec/hash-map.html, doesn't 
work either.

Nicholas Wilson <iamthewilsonator hotmail.com> writes:

On Saturday, 24 December 2016 at 00:57:04 UTC, Yuxuan Shui wrote:
 On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui 
 wrote:
 I tried this:

     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 
 'P':4];

 And got a "non-constant expression" error (with or without 
 'immutable').

 What's the correct way?

 This example here: https://dlang.org/spec/hash-map.html, 
 doesn't work either.

Is this at global scope?

You need to use a `shared static this() { ... }` to initialise it.

Stefan Koch <uplink.coder googlemail.com> writes:

On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui wrote:
 I tried this:

     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 
 'P':4];

 And got a "non-constant expression" error (with or without 
 'immutable').

 What's the correct way?

You cannot initialize an AA at compile-time.
Because AA's are provided by druntime and the ABI is not stable.

Carl Vogel <carljv gmail.com> writes:

On Saturday, 24 December 2016 at 11:21:11 UTC, Stefan Koch wrote:

 You cannot initialize an AA at compile-time.
 Because AA's are provided by druntime and the ABI is not stable.

This bit me when I was first starting out as well. I feel like 
there's really very little documentation on this, and I think 
most people's expect that you'd be able to initialize AAs from 
literals at compile time, just like normal arrays. Does anyone 
know if compile-time initialization of AAs is something that will 
be fixed?

Stefan Koch <uplink.coder googlemail.com> writes:

On Sunday, 25 December 2016 at 03:12:09 UTC, Carl Vogel wrote:
 Does anyone know if compile-time initialization of AAs is
 something that will be fixed?

I do intend to fix this.
The method is rather simple,
Given the aa implantation in d-runtime is made ctfe-able 
everything that causes trouble currently will just work.

Era Scarecrow <rtcvb32 yahoo.com> writes:

On Saturday, 24 December 2016 at 11:21:11 UTC, Stefan Koch wrote:
 On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui 
 wrote:
 What's the correct way?

 You cannot initialize an AA at compile-time.
 Because AA's are provided by druntime and the ABI is not stable.

  For fun I'm throwing together a quick AA struct that you can 
make at compile time. It's experimental and may be slow for 
compiling as it needs to find a size of numbers where the hashes 
don't overlap. Of course you can't add to it, you can't delete 
elements (key limitations) but you could in theory change the 
value; So this would be better for immutable objects or having a 
fixed number of pre-known keys.

  If anyone is interested I can share my sources fairly soon once 
I'm satisfied the required features are done. So far opIndex and 
generation works fine, but range/foreach over it is incomplete.

Stefan Koch <uplink.coder googlemail.com> writes:

On Sunday, 25 December 2016 at 05:45:14 UTC, Era Scarecrow wrote:
 On Saturday, 24 December 2016 at 11:21:11 UTC, Stefan Koch 
 wrote:
 On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui 
 wrote:
 What's the correct way?

 You cannot initialize an AA at compile-time.
 Because AA's are provided by druntime and the ABI is not 
 stable.

  For fun I'm throwing together a quick AA struct that you can 
 make at compile time. It's experimental and may be slow for 
 compiling as it needs to find a size of numbers where the 
 hashes don't overlap. Of course you can't add to it, you can't 
 delete elements (key limitations) but you could in theory 
 change the value; So this would be better for immutable objects 
 or having a fixed number of pre-known keys.

  If anyone is interested I can share my sources fairly soon 
 once I'm satisfied the required features are done. So far 
 opIndex and generation works fine, but range/foreach over it is 
 incomplete.

There are library solutions for AA like containers that can be 
used at compiletime.
Maybe you could help polishing them ?
So we can eventually get them into druntime ?

Jack Applegame <japplegame gmail.com> writes:

On Saturday, 24 December 2016 at 00:55:01 UTC, Yuxuan Shui wrote:
 I tried this:

     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 
 'P':4];

 And got a "non-constant expression" error (with or without 
 'immutable').

 What's the correct way?

This works:

void main() {
     immutable int[char] xx = ['Q':0, 'B':1, 'N':2, 'R':3, 'P':4];
}

If you want to initialize global variable, then

immutable int[char] xx;
shared static this() {
	xx = ['Q':0, 'B':1, 'N':2, 'R':3, 'P':4];
}