Wanted: a #RustLang tool with 4 panes:
- desired generated code
- an in progress proc-macro being written
- input #Rust code where the proc-macro is being applied
- a live updating view of the actual generated code with diff annotations against what was desired
If you want to go fancier, tie things in the output to the input and provide suggestions on where things are missing pre-expansion for the output to march the expectation. I feel like 90% of this can be accomplished today with tmux+a file watcher+direct rustc invocations using -Zunpretty=expanded, but it'd be lovely to have an actual tool for this.
![use iddqd::{IdOrdMap, IdOrdItem, id_upcast};
#[derive(Debug)]
struct User {
name: String,
age: u8,
}
// Implement IdOrdItem so the map knows how to get the key from the value.
impl IdOrdItem for User {
// The key type can borrow from the value.
type Key<'a> = &'a str;
fn key(&self) -> Self::Key<'_> {
&self.name
}
id_upcast!();
}
let mut users = IdOrdMap::<User>::new();
// You must pick an insertion behavior. insert_unique returns an error if
// the key already exists.
users.insert_unique(User { name: "Alice".to_string(), age: 30 }).unwrap();
users.insert_unique(User { name: "Bob".to_string(), age: 35 }).unwrap();
// Lookup by name:
assert_eq!(users.get("Alice").unwrap().age, 30);
assert_eq!(users.get("Bob").unwrap().age, 35);
// Iterate over users:
for user in &users {
println!("User {}: {}", user.name, user.age);
}](https://fedi.ml/photo/preview/640/670240 "use iddqd::{IdOrdMap, IdOrdItem, id_upcast};
#[derive(Debug)]
struct User {
name: String,
age: u8,
}
// Implement IdOrdItem so the map knows how to get the key from the value.
impl IdOrdItem for User {
// The key type can borrow from the value.
type Key<'a> = &'a str;
fn key(&self) -> Self::Key<'_> {
&self.name
}
id_upcast!();
}
let mut users = IdOrdMap::<User>::new();
// You must pick an insertion behavior. insert_unique returns an error if
// the key already exists.
users.insert_unique(User { name: \"Alice\".to_string(), age: 30 }).unwrap();
users.insert_unique(User { name: \"Bob\".to_string(), age: 35 }).unwrap();
// Lookup by name:
assert_eq!(users.get(\"Alice\").unwrap().age, 30);
assert_eq!(users.get(\"Bob\").unwrap().age, 35);
// Iterate over users:
for user in &users {
println!(\"User {}: {}\", user.name, user.age);
}")
![Rust compiler error output:
error[E0277]: the trait bound `CustomErrorHandler: ErrorHandler` is not satisfied
--> src/main.rs:5:17
|
5 | cnb_runtime(CustomErrorHandler {});
| ----------- ^^^^^^^^^^^^^^^^^^^^^ the trait `ErrorHandler` is not implemented for `CustomErrorHandler`
| |
| required by a bound introduced by this call
|
help: there are multiple different versions of crate `c` in the dependency graph
--> src/main.rs:1:5
|
1 | use b::CustomErrorHandler;
| ^ one version of crate `c` is used here, as a dependency of crate `b`
2 | use c::cnb_runtime;
| ^ one version of crate `c` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
--> ~/c-v0.2/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ^^^^^^^^^^^^^^^^^^^^^^ this is the required trait
|
::: ~/b/src/lib.rs:1:1
|
1 | pub struct CustomErrorHandler {}
| ----------------------------- this type doesn't implement the required trait
|
::: ~/c-v0.1/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ---------------------- this is the found trait
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `cnb_runtime`
--> ~/c-v0.2/src/lib.rs:3:41
|
3 | pub fn cnb_runtime(_error_handler: impl ErrorHandler) {}
| ^^^^^^^^^^^^ required by this bound in `cnb_runtime`](https://fedi.ml/photo/preview/640/582508 "Rust compiler error output:
error[E0277]: the trait bound `CustomErrorHandler: ErrorHandler` is not satisfied
--> src/main.rs:5:17
|
5 | cnb_runtime(CustomErrorHandler {});
| ----------- ^^^^^^^^^^^^^^^^^^^^^ the trait `ErrorHandler` is not implemented for `CustomErrorHandler`
| |
| required by a bound introduced by this call
|
help: there are multiple different versions of crate `c` in the dependency graph
--> src/main.rs:1:5
|
1 | use b::CustomErrorHandler;
| ^ one version of crate `c` is used here, as a dependency of crate `b`
2 | use c::cnb_runtime;
| ^ one version of crate `c` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
--> ~/c-v0.2/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ^^^^^^^^^^^^^^^^^^^^^^ this is the required trait
|
::: ~/b/src/lib.rs:1:1
|
1 | pub struct CustomErrorHandler {}
| ----------------------------- this type doesn't implement the required trait
|
::: ~/c-v0.1/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ---------------------- this is the found trait
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `cnb_runtime`
--> ~/c-v0.2/src/lib.rs:3:41
|
3 | pub fn cnb_runtime(_error_handler: impl ErrorHandler) {}
| ^^^^^^^^^^^^ required by this bound in `cnb_runtime`")