Apple Newton Utilities Guide de l'utilisateur télécharger pdf (Page 466)

100

101

CHAPTER 11

Data Storage and Retrieval

11-34 Using Newton Data Storage Objects

indexes: [{structure: 'slot, path: 'aSlot,

type: 'string}]

};

// register soup or retrieve already-registered soup

local myUsoup := RegUnionSoup('|myApp:mySig|, mySoupDef);

You can unregister a soup deﬁnition whenever you no longer need to create the

soup it deﬁnes. If your application is the only one that uses your soup, you need

only ensure that its deﬁnition is registered while the application is actually open. If

other applications use your soup, you may wish to leave its deﬁnition registered

even after your application is closed or removed; however, most applications

unregister their soup deﬁnitions at one of these times, if only to make that much

more memory available to other applications.

The following code fragment illustrates the use of the

UnRegUnionSoup function:

// unregister my soup def

UnRegUnionSoup (mySoupDef.Name, '|myApp:mySig|);

// don’t forget to set all unused references to nil

myUsoup := nil;

Retrieving Existing Soups 11

To retrieve your own union soups, you can use the RegUnionSoup function as

described in “Registering and Unregistering Soup Deﬁnitions” beginning on

page 11-33. Alternatively, you can call the

GetUnionSoupAlways global

function to retrieve any union soup by name.

Use of the

GetUnionSoupAlways global function is straightforward, as the

following example shows. Note that you can pass system-supplied constants to this

function to retrieve soups used by the system and the built-in applications. For

more information, see Chapter 19, “Built-in Applications and System Data.”

// retrieve "mySoup:mySig" union soup by name

local myUSoup := GetUnionSoupAlways("mySoup:mySig");

// retrieve soup used by built-in Names application

local names := GetUnionSoupAlways(ROM_CardFileSoupName);

Note that you can use the IsInstance utility function to determine whether a

speciﬁed soup is a union soup. Pass either of the symbols

'PlainSoup or

'UnionSoup as the value of the class parameter to this function, as shown in the

following code fragment.

IsInstance(mySoup, 'UnionSoup);

1 2 ... 461 462 463 464 465 466 467 468 469 470 471 ... 941 942

Commentaires sur ces manuels

Pas de commentaire

Apple Newton Utilities Guide de l'utilisateur Page 466

Commentaires sur ces manuels

Produits connexes et manuels pour Logiciel Apple Newton Utilities