insert_if_absent function:

• Can also be called as put_if_absent

• Can also be called as replace_if_absent

• Can also be called as {-}

Add a new entry to a map if it has no such key. The first argument should be an object. The second argument should be a key. The third argument should be a value. If the object has that key, it will not be replaced.

Examples:

• running: (insert_if_absent {}, "a", 1) will give: {"a": 1}

• running: (insert_if_absent {"a": 10, "b": 22}, "a", -1) will give: {"a": 10, "b": 22} Because the object already has a value with the a key.

• running: (insert_if_absent [], "a", 1) will return nothing

• running: (insert_if_absent {}, 1, 1) will return nothing

• running: (insert_if_absent {}, "1", ({} {} 1 1)) will return nothing