digging existing Forté code

what can be done of all that?

first stop ... 

using the previous thingies you may now be able to have a look at what is in $FORTE_ROOT/userapp/forte/cl0/forte.btd

a set of instruction is available here

an export of the Forté distributed apps is there

once imported have look at the plan named ‘ide’

enjoy browsing the Forté 4GL Workshop into the Forté 4GL Workshop ... mind boggling what the lads at Forté inc. managed to do. init?

 

internals of distributed apps

when an Object (eg mySO based on DistObj) is made remotely available Forté creates behind the scenes a class DistObjproxy that inherits from qqlo_Proxy and DistObj, it aplies to ANCHORED objects too.

there is only one class DistObjproxy created no matter how many SOs are based on that class, the multiple instanciation happens at runtime (the DistObjproxy is a class, the SO is an Object instanced using ImmobileInstanceAlloc as opposed to InstanceAlloc called on the ClassType when the ‘= new()’ statement is executed)

at runtime a method call on a SO translate into
GETGLOBALVAR 0
PUSHOBJECT 0 Rank of the SO in the list (looks like it's equal to SO_id - 1)
METHOD 3, 2


everything about GUIs and IRblock applies to distributed applications like forte.btd
but there are a couple of things that are not available directly in the runtime repository (at least I don’t know where)

when an application is distributed Forté creates 2 files suffixed .ace & .adf

the .ace file contains a serialised qqem_DistributionCatalogEntry used when econsole / escript lists the available, loadable distributions

the .adf is a qqem_StandardApp and contains the layout of SOs and their attributes (visibility, dialog duration)

so reading the .ace file makes you aware of the distributed layout.

internal Code storage __ qqrt_IRBlock

qqrt_IRBlock : how to get access to its attributes.

qqrt_IRBlock shows many attributes defined as pointers the good old $TOOCOMPLEX type.
unfortunately Forté as a 4GL does not allow you to set the pointee of a pointer, so just set pointer to the qqrt_IRBlock you want to inspect and load it in a BinaryData ... read at the requested offset something like

to get the list of pointer attributes

ptrIRB : pointer to char;
ptrIRB = (pointer to char)((pointer)(my_qqrtIRBlock));
myMemStream : MemoryStream;
myMemStream = new();
myMemStream.Open(SP_AM_READ_WRITE, TRUE);
myMemStream.UseData(ptrIRB, ClassType(qqrt_IRBlock).Size);


an Object is a pointer but the MemoryStream to be set requires a pointer to char ... so be it!


extracting the value of lets say qqrt_IRBlock. DoubleArray


linkedArray : BinaryData = new();
if my_qqrtIRBlock.DoubleCount > 0 then
voidBinaryData : BinaryData = new();
myMemStream.OffSet = 0x48;
myMemStream.ReadBinary(voidBinaryData, 4);
linkedArray.SetValue((pointer)(*(pointer to pointer)(voidBinaryData.Value)), my_qqrtIRBlock.DoubleCount * 8);
end;
BinaryData.Value is a pointer but we need to be able to read what is pointed as a pointer hence the silly recast (pointer to pointer) and the de-referencing and again the recast as (pointer)