Clojure read-string

2023-06-26

In my TicTacToe game, I need to store previous games in a database so that they can be played later. The object that I store a game as look something like:

{:date "Thu Jun 26 12:30:26 EDT 2023"
 :board [\_ \_ \_ \_ \_ \_ \_ \_ \_]
 :gamemode {:mode :pvc :difficulty :hard}}

Of course if we stored a pvp game, then we would not need the :difficulty part of :gamemode. But this is the general structure.

A problem arises when trying to read in the :board and :gamemode because it reads them in as strings when we want them to be a vector and map respectively.

So the internal data structure after reading in from the database might look like:

{:date "Thu Jun 26 12:30:26 EDT 2023"
 :board "[\\_ \\_ \\_ \\_ \\_ \\_ \\_ \\_ \\_]"
 :gamemode "{:mode :pvc :difficulty :hard}"}

This is where read-string comes in.

I can just call read-string on the board or gamemode and it will convert it to the correct type with data intact.

As an example:

(def obj {:date "Thu Jun 26 12:30:26 EDT 2023"
          :board "[\\_ \\_ \\_ \\_ \\_ \\_ \\_ \\_ \\_]"
          :gamemode "{:mode :pvc :difficulty :hard}"})

(read-string (:board obj))
; => [\_ \_ \_ \_ \_ \_ \_ \_ \_]

(read-string (:gamemode obj))
; => {:mode :pvc :difficulty :hard}