<div dir="ltr">The concerns are valid, but <div><br></div><div>1) adding these (the only possible / most general instances) will not break any existing code</div><div><br></div><div>2) cannot break any existing code except that which uses orphan instances (which will always break,so it doesnt matter)</div><div><br></div><div>3) brings better consistency, especially since bitraversable has the same instances?</div><div><br></div><div>also: i feel like some of the concerns brought up here really are about either </div><div><br></div><div>a) more desugaring for Tuples as Sized Lists? aka, i mean Hlist 3 a , when i write the type (a,a,a) ?</div><div>//</div><div>i've seen bugs in "production" from using the Maybe Monoid in a data aggregation (space leaks are the best!), that doesn't make the Maybe monoid of a semigroup any less useful!</div><div><br></div><div>so from my perspective, while yes, some folks use tuples for fixed size homogenuous collections, they are useful powerful tools in the algebra of types and functional programming jiggery pokery! There is no sound reason to cripple our official prepresentative of the the simple polymorphic product type formal, the "*" of our haskell and the eternal dual of the sum of our cases! ;)</div><div><br></div><div>strong +1, let the algebras roar :) <br></div><div><br></div><div>to be clear, the arguments against are valid, but i thnk they could be addressed by identifying the changes / tooling that would enable a better fitting of intent. buggy code happens, fix the root, not the symptom</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Apr 2, 2019 at 12:00 PM Eric Mertens <<a href="mailto:emertens@gmail.com" target="_blank">emertens@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Hi libraries@,</div><div><br></div>I'm also -1 on these instances. I'd prefer to see that the various tuples have instances that don't privilege one type variable over another. I find the existing instances for 2-tuples are already more likely to be used in error than intentionally, and even when used intentionally turn heads with their surprising behavior. I'd prefer to have Writer from transformers used, for example, when the non-symmetric treatment of the type parameters is intended.<div><br></div><div>Best regards,</div><div>Eric Mertens</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Apr 1, 2019 at 9:29 PM Fumiaki Kinoshita <<a href="mailto:fumiexcel@gmail.com" target="_blank">fumiexcel@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">I submitted <a href="https://gitlab.haskell.org/ghc/ghc/merge_requests/644" target="_blank">https://gitlab.haskell.org/ghc/ghc/merge_requests/644</a> but it might be still controversial. I'd like to get more opinions again.<br></div><div dir="ltr"><br></div><div>Here's the list of proposed instances:</div><div><br></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Foldable</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Foldable</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Traversable</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Traversable</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Functor</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">(</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-o">=></span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Applicative</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">(</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-o">=></span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monad</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Functor</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">(</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-o">=></span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Applicative</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">(</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">,</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monoid</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-o">=></span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-kt">Monad</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">((,,,)</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">a</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">b</span> <span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-n">c</span><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">)</span></code><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><br></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></div><div><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p"><code><span class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail-m_-6804735187369636405gmail-p">The absence of Traversable instances for tuples feels quite inconsistent given that there are Bitraversable instances </span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code></span></code><span style="font-family:monospace">already</span>.</div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail-m_-669777856019714462gmail-m_8275839210398922897gmail_signature">Eric Mertens</div>
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</blockquote></div>