Macro impl_mul_base_field 

macro_rules! impl_mul_base_field {
    ($alg_type:ty, $field_type:ty $(, ($type_param:ty, $param_name:ty))?) => { ... };
}

Given two structs Alg and Field where Alg implements From<Field>, implement Mul<Field> for Alg and Mul<Alg> for Field.

All are implemented in the simplest way by using From to map the Field element to an Alg element and then applying the native mul methods on Alg elements.