Trying to understand the DOORS DXL interpreter: in place data

Tags: dxl doors
Question!

I have a problem understanding why the interpreter does not accept this:

Object co = current Object
Object o  = object(co."Absolute Number")

The error is: "incorrect arguments for function (object)" / "incorrectly concatenated tokens". I verified that the type returned by co."Absolute Number" matches the expectation of Object object(int absno[, Module m]) as it was declared according to the DXL manual:

print type(co."Absolute Number")

which prints "Integer". Appears to be fine, but obviously, it is not.

It is not a problem of that particular attribute. co."Object Text" should return a string, but with that attribute as well, the interpreter does not recognize the data type.

Adding brackets at various places does not help. Trying to explicitly convert the returned attribute value to integer does not help. What helps is storing the returned value to an integer variable:

Object co = current Object
int no    = co."Absolute Number"
Object o  = object(no)

which I do not like because it introduces unused variables. What works as well is to use the standard string approach: convert the attribute value to string and then (back) to integer:

Object o  = object(intOf(co."Absolute Number" ""))

but that is rather hacky for me. What did I overlook?



Answers

The error Message appears at Compile Time, when co."Absolute Number" does not have a type, i.e. the Compiler does not look up predefined attributes or their types. The type function resolves correctly to the runtime Type of the absolute number. The create function inherits left handside type, which is Special in DXL

By : Thomas


You are correct, the DXL compiler is a bit strange with things like this. The best way is the one you mentioned:

Object co = current
Object o  = object(intOf(co."Absolute Number" ""))

Saving you from creating extraneous variables. Also, side note: you notice I left out Object after current as it is unnecessary.

This also begs the question though... why do you need to create co and o, since once this is executed they are both handles to the same object. You can just do:

Object o = current

Hope this helps.



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By: admin