rusteval
This crate provides traits and macros that make your application's structs and functions interactive.
Annotating a struct with #[derive(Interactive)]
, a struct's methods with #[Methods]
and a free function with #[Function]
will implement a set of traits,
that will allow you to access them as if Rust had a REPL.
Use this crate as an alternative for "print debugging" or as an ergonomic testing API.
This crate is no_std
compatible so you can use it to interact with embedded devices
and blink those LEDs from a USB or UART connection.
Usage
- Annotate everything you want to access with
Interactive
,Methods
andFunction
- Define a new struct that owns or holds references to the objects you want to access
- Derive
InteractiveRoot
for it - Use the trait's methods to evaluate a string
(the simplest one is
eval_to_string
but others allow for more custom behaviour) - Accessing a field will give you its Debug representation
- Calling a function or a method will parse its arguments and give you the Debug representation of its return value
Since this crate makes a lot of use of the Debug
trait the helper macro [PartialDebug
] is provided.
It implements Debug
for a struct replacing all fields that do not implement Debug
with a placeholder.
CLI Usage
Functions like get_all_field_names
are provided.
This makes it possible to implement things like auto-completion.
Have a look at the autocomplete example for how this might be done using the rustyline crate.
Example
use ;
;
let mut root = default;
assert_eq!;
assert_eq!;
// split_str_at("foobar", 3) => ("foo", "bar")
assert_eq!;
How it works
This crate makes use of the unstable specialization
feature, so it is only available on nightly.
Methods like try_as_interactive
are implemented on all types.
The method normally returns an error but in the specialized case
a trait object (&dyn Interactive
in this case) is returned.
The macros then implement getters that look something like this:
See the macro's documentation for more details.
Current limitations:
- Methods and functions can only be made interactive if their argument types are supported
- Enums are not supported