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Bug #767

closed

Labels and line numbers can't be referenced from a Gosub inside a Procedure or Function.

Added by Brian Flanagan about 3 years ago. Updated over 1 year ago.

Status:
Rejected
Priority:
High
Target version:
Start date:
05/30/2021
Due date:
% Done:

0%

Estimated time:
3:00 h
Affected version:

Description

This affects both the AOZ and Amiga manifests.

By definition, Labels and Line numbers should be Global.
Apparently, now, they are not. (These used to work.)

Problem with labels:

DoProcedure[1,2,3]
End

DoStuff:
    Print "Stuff"
Return

Procedure DoProcedure[a,b,c]
    Print a,b,c
    Gosub DoStuff
End Procedure

The above produces an Internal Error.

Modifying the code to use a line number instead of a label is revealing.

DoProcedure[1,2,3]
End

100 Print "Stuff"
Return

Procedure DoProcedure[a,b,c]
    Print a,b,c
    Gosub 100
End Procedure

Now the error message is "label not defined".

Similar results occur inside functions:

With labels:

result=DoFunction(1,2,3)
If result>0 Then Print result

End

DoStuff:
    Print "Stuff"
Return

Function "DoFunction",a,b,c
    Print a,b,c
    Gosub DoStuff
    done=123
End Function(done)

...and with line numbers.

result=DoFunction(1,2,3)
If result>0 Then Print result

End

100 Print "Stuff"
Return

Function "DoFunction",a,b,c
    Print a,b,c
    Gosub 100
    done=123
End Function(done)

From these tests, my assumption is that neither named labels, nor line numbers are functioning globally.

IMO, labels should have the same scope as where they are defined.
Any label or line number defined in the global scope should be, by definition, a global label/line number.

Since, in these examples, both the Line Number and the Label's scope is global, so they should be accessible inside procedures and functions.

Just FYI: In AMOS Pro, Gosub to a line number from inside a Procedure worked fine.
(Labels did not work. Apparently AMOS had the same problem as AOZ with global named labels.)

Actions #1

Updated by Brian Flanagan almost 3 years ago

  • Assignee set to Francois Lionet
  • Affected version changed from 1.0.0 (B8) to 1.0.0 (B10) u16

Re-tested in 1.0.0 (B8) u16 (9/14)
All 4 examples still fail.

Actions #2

Updated by Brian Flanagan over 2 years ago

Re-tested in 21 Oct 2021 version.
All 4 examples still fail.

NOTE: This was also a problem in AMOS Pro . Labels were not recognized inside a procedure whether local or global.

Since apparently, this doesn't work in AMOS or AOZ , I think I'd like to change the assumptions:

Let's assume that labels are by definition local .
This will necessitate the addition of a Global command for labels and line numbers:

Global Label 100,"MyLabel",200,"AnotherLabel"

That way, by default, the labels would be local to the container they're defined in, be it a Procedure, Function, Instruction, etc.

How do you think they should function at the top level?

My first thought would be that we'd have to specifically define them as Global using the suggested Global Label instruction in order to be able to use them inside other containers. This would be consistent with how we currently define Global variables. What do you think?

Actions #3

Updated by Baptiste Bideaux over 1 year ago

  • Status changed from New to Rejected

No jumps is allowed with Goto, Gosub from a procedure in AOZ. A procedure is a part of code that should works out of the main program code. The mixture of linear and procedural programming has always been a bad thing, even in the days of AMOS Pro.

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