ref: operations on references

type 'a ref = ref of mutable 'a

The type of references (mutable indirection cells) containing a value of type 'a.

value prefix ! : 'a ref -> 'a

!r returns the current contents of reference r. Could be defined as fun (ref x) -> x.

value prefix := : 'a ref -> 'a -> unit

r := a stores the value of a in reference r.

value incr : int ref -> unit

Increment the integer contained in the given reference. Could be defined as fun r -> r := succ !r.

value decr : int ref -> unit

Decrement the integer contained in the given reference. Could be defined as fun r -> r := pred !r.