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I've found that whenever I start a small web project in a new language, I always look for the "Flask" of that language. I love using a framework that gives the

I've found that whenever I start a small web project in a new language, I always look for the "Flask" of that language. I love using a framework that gives the bare essentials and nothing else. I don't use Rust, but your code examples look great! I understand that Rust has less opportunity for "magic" to clean things up (for example, in Python you can use a decorator to specify a route for a function), but otherwise it looks very clear. Awesome work!

TheHydroImpulse 11y ago
There's probably some opportunity to use custom annotations in Rust to achieve the same thing. #[route("/foobar")] fn user(_: &mut Request) -> PencilResult { // ... } However, procedural macros are unstable, but Rust is able to do amazing things with macros.
- fredsir 11y ago
  I know very little Rust, but I was actually looking at how this could be done in Rust some time ago, but I didn't get anything working. All the routes (e.g. /foobar and accompanying function) needs to be collected by the "router" somehow which begs for a global route-container that the route macro (like Flasks route decorator) would need to add routes to, similar to how it is done is Flask, and, well, yeah, I couldn't find a rusty way to do it. Bearing in mind that macros er unstable, can this be done in Rust, and if so, what would the process be?
  - TheHydroImpulse 11y ago
    There are a few different ways one could achieve this. The first options would be to generate a struct: struct RouteUser { route: &'static str, f: fn(_: &mut Request) -> PencilResult } Then given #[route("/user")] fn user(_: &mut Request) -> PencilResult {} You would hijack the `user` function to return an instance of the struct. fn user() -> RouteUser { // The actual function the user wrote: fn user(_: &mut Request) -> PencilResult { // ... } RouteUser { // Generated from the annotation argument route: "/user", f: user } } There is a difference between item decorators (`#[foobar]`) and regular procedural macros and I'm not completely sure if you could in-fact significantly change the given function. I haven't touched procedural macros in a while. To use the above route, you would simply have a `Route` trait perhaps. trait Route {} And implement it for each generated struct: impl Route for RouteUser {} Then you could use the route as app.route(user()); Which could be defined as fn route<R>(r: R) where R: Route { // ... }
    - fredsir 11y ago
      That seems like a good approach, although one thing is missing: when you use the route-decorator in Flask, the route is registered to the app object "via magic", whereas in your example, you still have to register it manually (`app.route(user())`). Now, I am partial to liking registering manually, like in your example and in Pencil itself, since that's clearer than having a lot of routes spread around in a whole lot of files that are magically registered, but just for the kicks, would it be possible to not having to manually register the route to the app object?
stormcrowsx 11y ago
I'm a huge fan of flask but I actually prefer the approach of not using decorators. Without decorators its easy to see all the paths in one area and they get type-checked in rust.
bsharitt 11y ago
>I always look for the "Flask" of that language. I always look for the "Sinatra" of that language.
zanny 11y ago
There is a language plugin for pythonic decorators in Rust: https://github.com/Manishearth/rust-adorn https://github.com/Manishearth/rust-adorn
sunng 11y ago
> "gives the bare essentials and nothing else" Rust is that thing exactly.
Manishearth 11y ago
You actually can use pythonish decorators in Rust, I wrote a proof of concept library for that: https://github.com/manishearth/rust-adorn https://github.com/manishearth/rust-adorn (it's not really intended to be used, but if folks want to use it I'm willing to clean it up)

TheHydroImpulse 11y ago

There's probably some opportunity to use custom annotations in Rust to achieve the same thing. #[route("/foobar")] fn user(_: &mut Request) -> PencilResult { // ... } However, procedural macros are unstable, but Rust is able to do amazing things with macros.

fredsir 11y ago
I know very little Rust, but I was actually looking at how this could be done in Rust some time ago, but I didn't get anything working. All the routes (e.g. /foobar and accompanying function) needs to be collected by the "router" somehow which begs for a global route-container that the route macro (like Flasks route decorator) would need to add routes to, similar to how it is done is Flask, and, well, yeah, I couldn't find a rusty way to do it. Bearing in mind that macros er unstable, can this be done in Rust, and if so, what would the process be?
- TheHydroImpulse 11y ago
  There are a few different ways one could achieve this. The first options would be to generate a struct: struct RouteUser { route: &'static str, f: fn(_: &mut Request) -> PencilResult } Then given #[route("/user")] fn user(_: &mut Request) -> PencilResult {} You would hijack the `user` function to return an instance of the struct. fn user() -> RouteUser { // The actual function the user wrote: fn user(_: &mut Request) -> PencilResult { // ... } RouteUser { // Generated from the annotation argument route: "/user", f: user } } There is a difference between item decorators (`#[foobar]`) and regular procedural macros and I'm not completely sure if you could in-fact significantly change the given function. I haven't touched procedural macros in a while. To use the above route, you would simply have a `Route` trait perhaps. trait Route {} And implement it for each generated struct: impl Route for RouteUser {} Then you could use the route as app.route(user()); Which could be defined as fn route<R>(r: R) where R: Route { // ... }
  - fredsir 11y ago
    That seems like a good approach, although one thing is missing: when you use the route-decorator in Flask, the route is registered to the app object "via magic", whereas in your example, you still have to register it manually (`app.route(user())`). Now, I am partial to liking registering manually, like in your example and in Pencil itself, since that's clearer than having a lot of routes spread around in a whole lot of files that are magically registered, but just for the kicks, would it be possible to not having to manually register the route to the app object?

stormcrowsx 11y ago

I'm a huge fan of flask but I actually prefer the approach of not using decorators. Without decorators its easy to see all the paths in one area and they get type-checked in rust.

bsharitt 11y ago

>I always look for the "Flask" of that language. I always look for the "Sinatra" of that language.

zanny 11y ago

There is a language plugin for pythonic decorators in Rust: https://github.com/Manishearth/rust-adorn https://github.com/Manishearth/rust-adorn

sunng 11y ago

> "gives the bare essentials and nothing else" Rust is that thing exactly.

Manishearth 11y ago

You actually can use pythonish decorators in Rust, I wrote a proof of concept library for that: https://github.com/manishearth/rust-adorn https://github.com/manishearth/rust-adorn (it's not really intended to be used, but if folks want to use it I'm willing to clean it up)