• Max Samukha (11/11) Dec 27 2020 Given a name bound to an alias sequence, what is a reliable way
• sighoya (11/22) Dec 27 2020 This should work:
• Max Samukha (4/14) Dec 27 2020 That will only work for type tuples. We need a general solution

Max Samukha <maxsamukha gmail.com> writes:

Given a name bound to an alias sequence, what is a reliable way 
to detect that?

import std.meta: AliasSeq;

alias a = AliasSeq!int;

static if (<is a an AliasSeq>) {

}

__traits(isSame, a, AliasSeq!a) could work but doesn't, because 
it flattens singletons, which means __traits(isSame, int, 
AliasSeq!int) is true. (A bug/bad design, IMO. If the intended 
behavior is not to flatten tuples passed to __traits, there is no 
reason to make a special case for singletons).

sighoya <sighoya gmail.com> writes:

On Sunday, 27 December 2020 at 12:23:26 UTC, Max Samukha wrote:
 Given a name bound to an alias sequence, what is a reliable way 
 to detect that?

 import std.meta: AliasSeq;

 alias a = AliasSeq!int;

 static if (<is a an AliasSeq>) {

 }

 __traits(isSame, a, AliasSeq!a) could work but doesn't, because 
 it flattens singletons, which means __traits(isSame, int, 
 AliasSeq!int) is true. (A bug/bad design, IMO. If the intended 
 behavior is not to flatten tuples passed to __traits, there is 
 no reason to make a special case for singletons).

This should work:
```
static assert(is(int == AliasSeq!int));
Drepl: static assert:  `is(int == (int))` is false
```

The most appropriate solution would be:
```
AliasSeq!int.stringof == (int);
```

But it wouldn't exclude false positives.

Max Samukha <maxsamukha gmail.com> writes:

On Sunday, 27 December 2020 at 18:25:10 UTC, sighoya wrote:
 This should work:
 ```
 static assert(is(int == AliasSeq!int));
 Drepl: static assert:  `is(int == (int))` is false
 ```

That will only work for type tuples. We need a general solution 
that would work for any alias tuple.

 The most appropriate solution would be:
 ```
 AliasSeq!int.stringof == (int);
 ```

 But it wouldn't exclude false positives

Yes, stringof is inadequate.