NAME
    ParentChunk -- Get the nesting context node for the given chunk.
SYNOPSIS
    parent = ParentChunk (cn)
      d0                  a0
    struct ContextNode *parent, *cn;
FUNCTION
    Returns a context node for the chunk containing the chunk for the
    given context node.  This function effectively moves down the context
    stack into previously pushed contexts.  For example, to get a
    ContextNode pointer for the enclosing FORM chunk while reading a data
    chunk, use: ParentChunk (CurrentChunk (iff)) to find this pointer.
    The ContextNode structure contains information on the type of chunk
    and its size.
INPUTS
    cn      - pointer to a context node.
RESULT
    parent  - pointer to the enclosing context node or NULL if none.
EXAMPLE
NOTES
BUGS
SEE ALSO
    CurrentChunk()