How to Create Application-specific Folders

One of the Newton 2.x OS Q&As
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This document was exported on 7/23/97.

How to Create Application-specific Folders (5/14/96)

Q: I would like to programmatically create folders so that they are available as soon as the application is open. What is the best approach to add application-specific folders?

A: You can use the global functions AddFolder and RemoveFolder to modify the folder set for a given application.

AddFolder(newFolderStr, appSymbol)

newFolderStr - string, the name of the new folder
appSymbol - symbol, application for local folder
result - symbol, the folder symbol of the newly added folder.

AddFolder takes a folder name and creates a new folder for the application.

AddFolder returns the symbol representing the tag value for the new folder. Please note that the symbol may be different from the value returned by using Intern() on the string. In particular, folder names with non-ASCII folders are supported. If a folder with the name already exists, the symbol for the pre-existing folder is returned and a new folder is not created.

There is a limit on the number of unique folders an application can support. If the limit is exceeded, AddFolder returns NIL and a new folder is not added. With the Newton 2.0 OS, the current limit is twelve global folders and twelve local folders.

RemoveFolder(folderSym, appSymbol)

folderSym - symbol, the folder symbol of the folder to remove
appSymbol - symbol, the application for which to remove the folder
result - undefined; do not rely on the return value of this function.

RemoveFolder can be used to remove a folder from the available list for an application. If items exist in a folder that is removed, the only way users can see the items is by selecting "All Items" from the folder list.