cacher | CakePHP caching plugin that caches query results | Caching library

Being an aspiring rustacean, I've been working my way through The Rust Programming Language book and being in the 13th chapter I was attempting to generalize the Cacher struct, that has as a purpose implementing lazy evaluation around a closure. While I was able to use generics to generalize the closure signature to any one parameter with any one output type, I can't figure out how to generalize this to closures with any number of params. I feel like there should be a way to do this.

I have been studying the official rust book, in the chapter on "closures" there is a demonstration of how to use cache with rust using structs and impl, then at the end they say that we add functions to the code, one of them start to use a dictionary so that we can have a multiple cache, I did that quickly, but then it says:

The second problem with the current Cacher implementation is that it only accepts closures that take one parameter of type u32 and return a u32. We might want to cache the results of closures that take a string slice and return usize values, for example. To fix this issue, try introducing more generic parameters to increase the flexibility of the Cacher functionality.

the relevant part of the code right now, with my modifications it looks like this.

Apologies for the following question. The compiler says that a temporary is created which is freed while still in use.

What I was trying to do is an example from the Rust book at https://doc.rust-lang.org/book/ch13-01-closures.html in which a Closure is supposed to update a HashMap in case the searched key is not found.

How can make this code compilable? Playground:

Every time I edit the code new errors arise, even following recommendations from the compiler.

I am trying to create a Cacher struct which will store calculated values in a HashMap. The calculation method will take one variable of type T, do calculations and return a value with the same type T. The type for this calculation callback will be Fn(T) -> T.

I figured out that value which will be a key of HashMap has to implement the Eq and Hash traits. It looked like everything should be working and I could compile my program without errors.

Then I wrote one test to check everything works as expected:

The problem is that my generic type T only accepts arguments from u32 and in this case I am trying to pass a generic value that I store in U.

Is there a way to cast generics to a specific type? What can I do to solve the problem?

I have a service worker that should return a cached file if it's of a certain type. If not, it should fetch the resource. I put the code that checks if the file is a certain type inside the fetch function. If it is, it returns the cached version. If not, it returns the fetched version. I have found out though, that it sends a network request for the fetch, then returns the cached version (duh).

I don't want this because it undos the purpose of serving the cached version of a large file instead of fetching it if possible. I realized I have to put the if then statement outside of the fetch, but that would mean that I am putting it in as a parameter. This is a problem, because it throws an error. So, I decided to put it inside a function. This returns an invalid response, so I don't know what I am doing wrong. It must be that the function inside the event.respondWith() must not be returning, but why?

My code is:

im currently using leaflet to get coord on click, but when i try to display the popup using the code on the documentation, i get this : << Uncaught TypeError: Cannot read property 'openPopup' of undefined >> i precise that i can see the map, she is created with no error logged, it's when i trigger the onclick event that i catch the error, ty in advance, here is my code :

I need some help. I have a menu, with links that I used like filters, to hide and show some galeries, that are associated with them. For exemple the link filter "Digital Painting" shows the galery "Digital Painting" since the galery "Traditional Painting" stays hide.

In my reasoning, I give the same classes to the link and the galery, who need to be linked together, for exemple the link filter "digital painting" and the galery "Digital Painting" have the same class "digital-painting".
So if the class link filter and the class of a galery coincide, I show the galery who had the same class of the link actually clicked on, and I hide the others galeries.

///// * Result of the code below : When I clic on the first link, all galeries are display, and if I clic on the second link, all galeries are hidden.

Do you know how ?

-- French : J’ai un menu qui me sert de filtre, pour afficher et cacher des galeries différentes. J’ai donc mis la même classe aux éléments qui doivent être reliés. Dans mon raisonnement, si la classe de la galerie correspond à la classe du lien cliqué alors elle s’affiche sinon elle reste cachée. Résultat du code ci-dessous : lorsque je clique sur le premier lien du menu toutes les galeries s’affichent, si je clique sur le second toutes les galeries se masquent :/

Code JS :

I am trying to improve the Cacher type described in The Rust Programming Language. One of the improvements suggested states that Cacher should be usable with many types. To do this, I have written the following code: