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Entries 11 – Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) User Manual

Page 449

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C H A P T E R 1 1

Data Storage and Retrieval

About Data Storage on Newton Devices

11-17

Figure 11-5

Cursor presents discontiguous index key values contiguously

Entries

11

An entry is a special kind of frame that resides in a soup. Valid entries can be
created only by system-supplied methods provided for this purpose—you cannot
create an entry by creating a frame having certain slots and values. The entry that
these methods create consists of the frame presented to the entry-creation method,
along with copies of any data structures the frame references, as well as copies of
any data structures those structures reference, and so on. An exception to this rule
is that

_proto

slots are not saved in soup entries. Circular references within an

entry are allowed.

1 2 3 4 5

6 7 8 9

2

4

6

2 4

6

beginKey

Indexed entries

Eliminate more
entries

Valid entries
in black

Valid entries as
presented by
cursor

Select subrange
of valid entries

endExclKey

indexValidTest: func (key)

begin

(key MOD 2 = 0)

end

subrange of index key values

2 3 4 5

6 7