pair | create low memory key/value objects in Go | Key Value Database library

foldl' only evaluates the intermediate state to weak head normal form—i.e. up to the first constructor. That's the most a generic function can do, and what functions that are called "strict" generally do. Evaluating (x1, y1) <+> (x2, y2) until it looks like a constructor gives (x1 + x2, y1 + y2), where the parts are still unevaluated (they have been "protected" by the (,)). Through the iteration, foldl' being strict keeps the state in the form (_, _) instead of (_, _) <+> (_, _) <+> ..., but the _s grow into huge unevaluated terms of form _ + _ + _ + ....

Modify <+> to evaluate the additions before it exposes the constructor.

My guess is that you have an old version of platform-tools/adb installed somewhere (you can verify this by running which adb in your command prompt).

You can find the pathway to the platform-tools/adb you want to use in Android Studios under Settings -> Appearance & Behavior -> System Settings -> Android SDK.

Inside of this folder should be another folder called "platform-tools".

File -> Invalidate Caches -> Invalidate and Restart

There's a quick-and-dirty approach, which will kinda-hopefully-maybe do what you asked for, and will not even copy the data at all... but the downside is that you can't be certain it will work. It relies on undefined behavior, and can thus not be recommended. I'm describing it because I believe it's what one imagines, intuitively, that we might be able to do.

So, it's about using std::span with re-interpretation of the vector data:

I think this gets you pretty close; might just need to adjust the various name columns and drop the extra data (I kept the grouping column).

The main idea is to recursively use pd.json_normalize with pd.concat for all availalable children levels.

EDIT: Put everything into a single function and added section to collapse the name columns like the expected output.

#[main] is an old, unstable attribute that was mostly removed from the language in 1.53.0. However, the removal missed one line, with the result you see: the attribute had no effect, but it could be used on stable Rust without an error, and conflicted with imported attributes named main. This was a bug, not intended behaviour. It has been fixed as of nightly-2022-02-10 and 1.59.0-beta.8. Your example with use tokio::main; and #[main] can now run without error.

Before it was removed, the unstable #[main] was used to specify the entry point of a program. Alex Crichton described the behaviour of it and related attributes in a 2016 comment on GitHub:

Ah yes, we've got three entry points. I.. think this is how they work:

• First, #[start], the receiver of int argc and char **argv. This is literally the symbol main (or what is called by that symbol generated in the compiler).
• Next, there's #[lang = "start"]. If no #[start] exists in the crate graph then the compiler generates a main function that calls this. This functions receives argc/argv along with a third argument that is a function pointer to the #[main] function (defined below). Importantly, #[lang = "start"] can be located in a library. For example it's located in the standard library (libstd).
• Finally, #[main], the main function for an executable. This is passed no arguments and is called by #[lang = "start"] (if it decides to). The standard library uses this to initialize itself and then call the Rust program. This, if not specified, defaults to fn main at the top.

So to answer your question, this isn't the same as #[start]. To answer your other (possibly not yet asked) question, yes we have too many entry points.

As far as I understood, here's a dplyr suggestion:

Here's my current understanding, which could be incomplete or incorrect. A verification would be appreciated.

C++20 renamed strongly happens before to simply happens before, and introduced a new, more relaxed definition for strongly happens before, which imposes less ordering.

Simply happens before is used to reason about the presence of data races in your code. (Actually that would be the plain 'happens before', but the two are equivalent in absence of consume operations, the use of which is discouraged by the standard, since most (all?) major compilers treat them as acquires.)

The weaker strongly happens before is used to reason about the global order of seq-cst operations.

This change was introduced in proposal P0668R5: Revising the C++ memory model, which is based on the paper Repairing Sequential Consistency in C/C++11 by Lahav et al (which I didn't fully read).

The proposal explains why the change was made. Long story short, the way most compilers implement atomics on Power and ARM architectures turned out to be non-conformant in rare edge cases, and fixing the compilers had a performance cost, so they fixed the standard instead.

The change only affects you if you mix seq-cst operations with acquire-release operations on the same atomic variable (i.e. if an acquire operation reads a value from a seq-cst store, or a seq-cst operation reads a value from a release store).

If you don't mix operations in this manner, then you're not affected (i.e. can treat simply happens before and strongly happens before as equivalent).

The gist of the change is that the synchronization between a seq-cst operation and the corresponding acquire/release operation no longer affects the position of this specific seq-cst operation in the global seq-cst order, but the synchronization itself is still there.

This makes the seq-cst order for such seq-cst operations very moot, see below.

The proposal presents following example, and I'll try to explain my understanding of it:

Apparently this is a long time know bug with a combination of MSVC STL implementation choices and Standard specifications...

The issue I found when I was going to submit a bug report, from 2018: https://developercommunity.visualstudio.com/t/C2280-when-modifying-a-vector-containing/377449

• This error is present in MSVC 2017 and after.
• It seems like not going to be fixed. (see @Alex Guteniev's comment)

The explanation given: https://www.reddit.com/r/cpp/comments/6q94ai/chromium_windows_builds_now_use_clangcl_by_default/dkwdd8l/

• There is a workaround: vector>>, where the Wrapper is also a non-copyable type.

One work around would be to use your map2_dfr code, but then bind the columns that are needed to the map2_dfr output. Though you still have to drop the names column.