Hi mike,
Your problem is about to calling a function with a list of arguments,
which is independent of varargs. Take a look at the "apply" function.
It does what you're looking for.
Cheers
-Patrick
On Sep 14, 2:47 am, Michael Ossareh <ossa...@gmail.com> wrote:
> Hi,
>
> I don't fully understand how to make real use of varargs and
> destructuring. c.c.sql/create-table is defined as follows:
>
> (create-table name & specs)
>
> Called as follows:
>
> (c.c.sql/create-table
> :tblname
> [:cola :text "NOT NULL" "PRIMARY KEY"]
> [:colb :number "NOT NULL"]
> [:colc :blob "NOT NULL")]
>
> I want to store my table definitions in a data structure (I'm open to
> which one) such that I can get access to table names later on. However
> if I store the definitions in a vector which each element is a vector
> of arguments to create-table I'm not able to pass the correct
> arguments to create-table.
>
> An example of the data structure:
>
> (def schema
> [[:users
> [:id :text "PRIMARY KEY" "NOT NULL"]
> [:domain :text "NOT NULL"]
> [:email :text :unique "NOT NULL"]
> [:password :text "NOT NULL"]
> [:name :text "NOT NULL"]
> [:created :bigint "NOT NULL"]
> [:last_login :bigint]]
>
> [:user_token
> [:token :text :unique "PRIMARY KEY" "NOT NULL"]
> [:user_id :text "NOT NULL" "REFERENCES users(id) ON DELETE CASCADE"]
> [:client :text "NOT NULL"]
> [:created :bigint "NOT NULL"]
> [:last_used :bigint]]])
>
> (defn x [a & b] (prn (str "a: " a)) (prn (str "b: " b)))
>
> (map (fn [y] (x (first y) (rest y))) schema)
>
> results in:
>
> ("a: :users"
> "b: (([:id :text \"PRIMARY KEY\" \"NOT NULL\"] [:domain :text \"NOT
> NULL\"] [:email :text :unique \"NOT NULL\"] [:password :text \"NOT
> NULL\"] [:name :text \"NOT NULL\"] [:created :bigint \"NOT NULL\"]
> [:last_login :bigint]))"
> "a: :user_token"
> "b: (([:token :text :unique \"PRIMARY KEY\" \"NOT NULL\"] [:user_id
> :text \"NOT NULL\" \"REFERENCES users(id) ON DELETE CASCADE\"]
> [:client :text \"NOT NULL\"] [:created :bigint \"NOT NULL\"]
> [:last_used :bigint]))")
>
> if I call create-table instead of `x` it gets two arguments, (first y)
> and a vector containing the elements in (rest y) instead of (first y)
> and each of the elements in (rest y).
>
> How is it possible for me to flatten b such that when passed to
> c.c.sql/create-table its fn arguments are satisfied? I feel like
> partial need to be used, however I haven't been able to figure it out.
>
> Any help much appreciated!
>
> Cheers,
>
> mike
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