Manipulating the store

The store is a map from expressions to integer values:

store : expression -> integer

Some of the common functions that are used to manipulate the map are described next. For a full listing, see The store.

SET_STATE(t, v)

Map expression tree t to v. Any prior mapping is removed.

GET_STATE(t, v)

Retrieve the mapping for t. If it exists, GET_STATE returns true and stores the value in v. Otherwise, GET_STATE returns false and v is undefined.

MATCH_STATE(t, v)

Return true if t is mapped to v.

CLEAR_STATE(t)

Remove any mapping for t.

COPY_STATE(dst, src)

First, CLEAR_STATE(dst). Then, if src is mapped, copy its mapping to dst.

FOREACH_IN_STORE(t, v)

Using a loop, bind t and v to all of the (expression tree, value) pairs in the store. The bindings are retrieved in an undefined order. The store should not be modified during the iteration.