Method declare_input

Declare a new *input* to the computation. See [Embeddable::declare_input] ## Arguments nice_name: the in-program name of the input ty: the type visibility: who should know this input mangle_name: if true, then creates a unique version of nice_name, and declares that. Otherwise, uses nice_name.

(
        &mut self,
        nice_name: VarName,
        ty: &E::Ty,
        visibility: Option<PartyId>,
        precomputed_value: Option<E::T>,
        mangle_name: bool,
    )