https://issues.dlang.org/show_bug.cgi?id=4508

Vlad Levenfeld <vlevenfeld@gmail.com> changed:

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https://issues.dlang.org/show_bug.cgi?id=4508

bearophile_hugs@eml.cc changed:

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--- Comment #1 from bearophile_hugs@eml.cc ---
I think this is a bad idea, in this form. So I suggest to close this issue.

I prefer this syntax much more:

static foreach(i; 0..tup.length) {

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https://issues.dlang.org/show_bug.cgi?id=4508

Nick Treleaven <nick@geany.org> changed:

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--- Comment #2 from Nick Treleaven <nick@geany.org> ---
`foreach (e; seq)` works at compile time for an AliasSeq, so I don't see why
`foreach (i; low..high)` can't make `i` known at compile-time if the bounds are
known.

I think we should rename this bug to apply to any CT-knowable index in a ForeachRangeStatement.

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https://issues.dlang.org/show_bug.cgi?id=4508

ag0aep6g@gmail.com changed:

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--- Comment #3 from ag0aep6g@gmail.com ---
(In reply to Nick Treleaven from comment #2)
> `foreach (e; seq)` works at compile time for an AliasSeq, so I don't see why
> `foreach (i; low..high)` can't make `i` known at compile-time if the bounds
> are known.

Can `i` be made known at compile-time without unrolling the loop (in the binary)? Surely we don't want to unroll every loop that can possibly be unrolled. For example, it would be very surprising if the compiler unrolled a loop like `foreach (i; 0 .. uint.max) writeln(i);`, generating gigabytes of machine code.

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https://issues.dlang.org/show_bug.cgi?id=4508

--- Comment #4 from Nick Treleaven <nick@geany.org> ---
In that case, perhaps we could use `static foreach` as in comment 1.

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https://issues.dlang.org/show_bug.cgi?id=4508

Dmitry Olshansky <dmitry.olsh@gmail.com> changed:

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             Status|NEW                         |RESOLVED
                 CC|                            |dmitry.olsh@gmail.com
         Resolution|---                         |FIXED

--- Comment #5 from Dmitry Olshansky <dmitry.olsh@gmail.com> ---
With static foreach you can do this, and AFAICT is exactly what is required:

import std.typecons;

void main() {
    auto tup = tuple(1, "foo", 3.0).expand;
    static foreach(i; 0..tup.length) {{
        auto val = tup[i];
    }}
}

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