leanpub | Build leanpub books | Frontend Framework library

Raw JSON Path doesn't do this, but depending on the implementation you're using, it might be supported.

We're currently in progress writing a formal specification. One of the open issues is the breadth of expression support we want. Feel free to add a comment. Once the spec is defined and published, I imagine most implementations will update to adhere.

It's hard to understand what Haskell exactly does in such cases, because of optimization. Haskell only mandates what is the result, not how it is obtained.

Some possibilities:

• fmap Sum performs a list scan, and copies each cell and each element;
• fmap Sum performs a list scan, and copies each cell but not the elements (the new cells point to the old elements);
• fmap Sum does not scan the list at all and is automatically optimized to a no-op.

I tried godbolt.org to inspect the generated Core and assembly. Note that it still uses an old GHC 8.6.2. Still, I turned optimization on (-O2) and compiled

would not auto&& e = std::move(ms) cause ms to immediately have its contents "moved"/"stolen"/"invalidated"?

std::move() only prepares ms to be moved, it doesn't outright move from it. That's why e is a reference to a MyStruct, not an actual MyStruct object.

I am not exactly sure what is the desired output but have a look at this.

You can see the outer level are genres, followed by nested publishers with nested books within.

1. Firstly, I got all the genres.
2. Then I got the books and publishers with $lookup.
3. I used $unwind to separate publishers.
4. I added books with $addFields to each publisher for filtering it later.
5. I used $group to get relevant elements and $addToSet to make an array of publishers.
6. Finally, I used $project with $map and $filter to get relevant books for each publisher.

I think your looking for $lookup with a pipeline like this:

https://mongoplayground.net/p/H_OsKvN_npf

If you use the raw_tex extension, you can simply add \part wherever you want it. Add +raw_tex to the input format when you run Pandoc to enable it, e.g.

This is called Destructuring.

From the linked page:

In order to find one book you can use:

I can answer the first question with certainty:

When you call the function System.out.println, it will do the following:

Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes print(String) and then println().

Source: https://docs.oracle.com/javase/8/docs/api/java/io/PrintStream.html#println-java.lang.Object-

And the subsequent call of String.valueOf(x) will do the following:

If the argument is null, then a string equal to "null"; otherwise, the value of obj.toString() is returned.

Source: https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#valueOf-java.lang.Object-

Since this refers to an instance of Hello it will just call the Hello.toString() method on the given instance - callstack: