Function mentat_ffi::store_value_for_attribute

#[no_mangle]
pub unsafe extern "C" fn store_value_for_attribute(
    store: *mut Store, 
    entid: c_longlong, 
    attribute: *const c_char
) -> *mut ExternResult

Returns an ExternResult containing the Binding associated with the attribute as :namespace/name for the given entid. If there is a value for that attribute on the entity with id entid then the value is returned in ok. If there no value for that attribute on the entity with id entid but the attribute is value, then a null pointer is returned in ok. If there is no Attribute in the Schema for the given attribute then an error is returned in err.

Safety

Callers are responsible for managing the memory for the return value. A destructor destroy is provided for releasing the memory for this pointer type.

TODO: list the types of error that can be caused by this function