Proposal: a macro for expressions like WRITETIME(field)/TTL(field)

[kakserpom]

Example:

#[charybdis_model(
    table_name = users,
    partition_keys = [id],
    clustering_keys = [],
)]
pub struct User {

    id: Uuid,
    #[charybdis_expr("WRITETIME(id)")]
    id_writetime: Option<Timestamp>,
    tags: Set<Text>,
    post_ids: List<Uuid>,
}

id_writetime will be a read-only field (ignored by insert() and update())

SELECT queries will include WRITETIME(id) and the column will be mapped to id_writetime

What do you think?

[GoranBrkuljan]

I would recommend the following syntax:

#[charybdis_model(
    table_name = users,
    partition_keys = [id],
    clustering_keys = [],
)]
pub struct User {
    id: Uuid,
    username: Uuid,
    #[charybdis(writetime = "username")]
    username_wt: Option<Timestamp>,
}

Note that we can not use writetime on primary key columns, so we need to panic! if users try to.

[kakserpom]

Looks good. Will you implement this? :-)

[GoranBrkuljan]

I am quite busy these few weeks. I will probably just do small updates and fixes until mid-July.