std.array: Allow joining constant arrays

[CyberShadow]

Fixes this:

const string[] arr = ["apple", "banana"];
arr.join();

[monarchdodra]

I wish we had an Ifti! template for this. This would help solve the issue of const ranges all around.

[Poita]

I'm always a bit concerned with liberal use of Unqual like this. Surely this would break with a class-type const range, e.g. const InputRange!E? I'm not sure you can just cast away the const like that, but maybe I'm wrong.

[monarchdodra]

Surely this would break with a class-type const range

As far as I can tell, the change is fine because nothing actually ever gets casted away. This merely relaxes the constraints, but the function still operates on the actual types. The types stored are still the raw RoR and ElementType!RoR

This means that while our constraints will now accept const ranges, nothing guarantees the implementation will actually compile correctly.

So I don't think this could actually lead to undefined behavior (which is good), but can lead to compile errors (which is bad), but accepts code that was (arguably) valid, but previously rejected (which is bad).

[CyberShadow]

I guess instead of Unqual we need CanRemoveHeadConstByAssignment or something like that?

[Poita]

I currently have a pull request for CompatibleUnqual, which does exactly
that.
On 25 Jan 2014 21:10, "Vladimir Panteleev" notifications@github.com wrote:

I guess instead of Unqual we need CanRemoveHeadConstByAssignment or
something like that?

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Reply to this email directly or view it on GitHubhttps://github.com//pull/1865#issuecomment-33300745
.

[CyberShadow]

I currently have a pull request for CompatibleUnqual, which does exactly that.

What's the pull request number? What's its status, is it merged? Does it make this one obsolete?

[Poita]

It's here: #1881

It's not merged, and unknown whether or not it will be.

It doesn't make your change obsolete. It would just change your Unquals to CompatibleUnquals, so that it's more correct for ranges with indirections.

I think we should still merge your change in the meantime.

LGTM

[ghost]

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