Procedural Macros

fvm_state #

To import in your actor everything needed by the procedural macro it is recommended to use the whole state module:

use fvm_rs_sdk::state::*;

There are two things to know while using this procedural macro:

• The procedural macro does not work on structure with lifetime or generic parameters to prevent problems around Serialization and Deserialization.
• When using the macro on a structure, fields that are not public will not be stored in the state.

fvm_actor #

The procedural macro to annotate your actor’s interface can be found in the actor module:

use fvm_rs_sdk::actor::fvm_actor;

This macro will parse the annotated implementation and generate a proper invoke() function that will become the entry point of your actor.

Limitations #

• The implementation with #[fvm_actor] have to be the implementation of the structure with #[fvm_state].
• Only one implementation can be written with #[fvm_actor] as it will generate compilation conflicts otherwise (multiple invoke() functions declared).
• Implementation with generics or lifetime are not supported.

fvm_export #

The procedural macro to annotate your actor’s entry point in the implementation representing your actor’s interface. It can be accessed in the actor module:

use fvm_rs_sdk::actor::fvm_export;

Limitations #

• When specifying an export it has to be used with a valid binding method attribute to specify its internal dispatch value (e.g.: #[fvm_export(method_num=1)]). Currently the only supported binding method is method_num.
• A method annotated with #[fvm_export] has to be public.
• Methods with generic types or lifetimes as arguments or return are not supported.
• Only a “few” types are supported. The list can be found here.

fvm_payload #

#[fvm_payload] is used to annotate custom structures that will be used either as parameters or return value for exposed methods. To use the macro it is advised to import the whole payload module:

use fvm_rs_sdk::payload::*;

There are two things to know while using this procedural macro:

• The procedural macro does not work on structure with lifetime or generic parameters to prevent problems around Serialization and Deserialization.