Structure References

References to parts of structures within program code are not hard to handle. The basic principles are:

• Every expression has a type ( symtype).

• Types form a tree structure (a graph when pointers to types are included, but still treated as a tree).

• The structure references in source code specify a traversal down the type tree.

• A reference to a part of a structure depends on the type of the structure; the results of the reference are:
  • An address expression for the substructure.

  • A new type for the substructure.

(code, type) → (code', type')

Repeated application of this procedure handles even complicated references.

There are several basic cases: arrays, records, and pointers.