Routing Interface

Using Routing

If you need to read the

body

slot within the

fields

frame, note that it might

contain an alias. In order to access it you must get the format and send it the

ResolveBody

message, like this:

theFormat := GetCurrentFormat(fields);
resolvedBodySlot := theFormat:ResolveBody(fields);

The

ResolveBody

method returns the data in the

body

slot whether or not it is

referenced by an alias, so you can always use it.

You can store information you obtain from an auxiliary view in the

fields

frame,

preferably in the

body

slot (or if

body

contains an alias, in the entry the alias

points to). If you store data from the auxiliary view in a different slot, be sure the
slot name has your developer signature appended to avoid future slot name
conflicts.

Registering Routing Formats

21

All routing formats are specified as view definitions and are registered with the
system by means of the global function

RegisterViewDef

. The formats that

handle data types other than

'view

are not actually views, but they are registered

as view definitions to take advantage of the central registration mechanism.
Registering formats in this way makes them available to all applications in the
system. Routing formats are specially identified in the view definition registry
because the

type

slot of all routing formats is set to the symbol

'routeFormat

(or

'printFormat

in some ROM versions).

Register formats with the class of the object you want them to act on. Here is an
example of registering a format:

RegisterViewDef(myPrintFormat, '|myDataClass:SIG|);

This call registers the format

myPrintFormat

as working with data whose

class is

'|myDataClass:SIG|

. If the class of any target data object is

'|myDataClass:SIG|

, the format

myPrintFormat

will be available when

that item is routed. The fact that this print format (with a

'view

data type) has

been registered means that you can print and fax that class of data items. This
mechanism enables you to have separate routing formats (and thus routing actions)
for individual views, if they use different data classes for data, rather than using the
same formats (and routing actions) for all views in an application.

Typically, your application registers routing formats when it is installed, in its part

InstallScript

function, and unregisters formats in its

RemoveScript

function. You use the function

UnRegisterViewDef

to unregister routing formats.

In an application part

InstallScript

function, when registering your

routing formats, you must not use the Newton Toolkit function

GetLayout

to obtain a reference to the routing format layout, so that you can pass it to