Compiler check for missing ProcedureReturn?

[hoerbie]

Hi,

after searching a problem in an actual program for hours, I think that it maybe would be helpful, if a Procedure for example is declared with a return parameter long like

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Procedure.l name()

or other return type and the

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ProcedureReturn var

is missing in the Procedure, the compiler should throw a warning/error.

Greets, hoerbie

[jacdelad]

Please excuse my ignorance, but can you give me a short example to understand how it causes problems to forget the ProcedureReturn?

[Tenaja]

Pb returns 0 by default, for every procedure. When you declare it with something other than Int--because you require a return value-- getting that default value can be a tricky thing to chase down.


The smart thing to do, if you require a valid return value, is to, well, just do it, but if you want to make it easy to see if you skipped it, then put and invalid value (error code) at the bottom. Then, check it for the error code on the receiving end.

[BarryG]

+1. I agree with hoerbie. If you're defining a type with the Procedure command, then you're obviously intending to use ProcedureReturn with it, so if the compiler gets to the end of the procedure and hasn't seen one, it could raise an error to alert you. This has happened to me before where I had ProcedureReturn commented out during a test, and forgot to uncomment it again.

[HeX0R]

-1

[Marc56us]

-1 also
No need to slow down the compilation with additional checks when user forgetting does not cause a compilation error.

[mk-soft]

Pb returns 0 by default, for every procedure. When you declare it with something other than Int--because you require a return value-- getting that default value can be a tricky thing to chase down.

That not exact. ProcedureReturen without variable return the eax/rax register

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Procedure foo()
  CompilerSelect #PB_Compiler_Processor
    CompilerCase #PB_Processor_x64
      !mov rax, 100
    CompilerCase #PB_Processor_x86
      !mov eax, 100
  CompilerEndSelect
  ProcedureReturn
EndProcedure

Debug foo()

PB-Help: If no value is specified for ProcedureReturn, the returned value will be undefined (see inline assembly for more information).

[infratec]

That can be very tricky, because some coders do something like this:

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Procedure.a Test(i.i)
  
  Select i
    Case i = 1
      ProcedureReturn 10
    Case i = 2
      ProcedureReturn 9
  EndSelect
  
EndProcedure

I 'forgot' to return something if nothing fits.
But there are ProcedureReturns inside.

[mk-soft]

After ASM or C-Backend output, the result of the procedure is always returned as NULL if ProcedureReturn is not called.

[infratec]

@mk-soft
But this is not the problem.

The wish is that this is detected by the compiler.
But I think that this is nearly impossible with my example.

And Null can be a vaild result of the procedure, so it is also not detectable if the ProcedureReturn is missing or not.

[mk-soft]

Purebasic makes no distinction between a sub or a function. So you have to make sure yourself that a valid return value is assigned to a function.

[juergenkulow]

-1

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; C return value 
Procedure.w foo()
  ! return 4711;
EndProcedure

Debug foo()
CompilerIf #PB_Backend_C<>#PB_Compiler_Backend
  CompilerError "C Backend only, please use PB 6.00 Beta"
CompilerEndIf