Attribute Macro sylvia::interface

#[interface]

Macro generating messages from contract trait.

Example usage

#[sylvia::interface(module=msg)]
trait Cw4 {
    type Error: From<StdError>;

    #[msg(exec)]
    fn update_admin(&self, ctx: (DepsMut, Env, MessageInfo), admin: Option<String>) -> Result<Response, Self::Error>;

    #[msg(exec)]
    fn update_members(&self, ctx: (DepsMut, Env, MessageInfo), remove: Vec<String>, add: Vec<Member>)
        -> Result<Response, Self::Error>;

    #[msg(query)]
    fn admin(&self, ctx: (Deps, Env)) -> Result<AdminQueryResponse, Error>;

    #[msg(query)]
    fn member(&self, ctx: (Deps, Env), addr: String, at_height: Option<u64>) -> Result<MemberQueryResponse, Error>;
}

This would generate output like:

pub mod msg {

    #[derive(serde::Serialize, serde::Deserialize, Clone, Debug, PartialEq, schemars::JsonSchema)]
    #[serde(rename_all = "snake_case")]
    pub enum ExecMsg {
        UpdateAdmin { admin: Option<String> },
        UpdateMembers {
            remove: Vec<String>,
            add: Vec<Member>,
        },
        AddHook { addr: String },
        RemoveHook { addr: String },
    }

    impl ExecMsg {
        pub fn dispatch<C: Cw4>(contract: &C, ctx: (DepsMut, Env, MessageInfo))
            -> Result<Response, C::Error>
        {
            // Some dispatching implementation
        }
    }
}

And similar `Query` structure for handling queries.

Parameters

interface attribute takes optional parameters:

• module - defines module name, where all generated messages would be encapsulated; no additional module would be created if not provided

Attributes

Messages structures are generated basing on interface trait method attributed with #[msg(msg_type, ...). Msg attribute takes as its first argument type of message it is supposed to handle:

• exec - this is execute message variant
• query - this is query message variant

In case of query it is possible to pass second argument which is it’s ResponseType. This is required in case of aliased results wrapping their ResponseType. Example for member query

    #[msg(query, resp=MemberQueryResponse)]
    fn member(&self, ctx: (Deps, Env), addr: String, at_height: Option<u64>) -> Result<MemberQueryResponse, Error>;

For now #[msg(...)] attribute doesn’t support anymore data on #[interface] elements, but it may be extended in future.