OpenEuphoria

Re: Unusual EU Problem (must see)

• Posted by Juergen Luethje <j.lue at gmx.de> Aug 16, 2003
• 473 views

Al wrote:

> Juergen Luethje wrote:
>>
>>
>> Al wrote:
>>
>> <snip>
>>
>>> function FunctionAAA()
>>>   atom param
>>>   param=1
>>>   return FunctionBBB(param)
>>> end function
>>>
>>> Looks normal, doesnt it?
>>> Well, you would think so anyway...but
>>>
>>> FunctionBBB() never executes!
>>>
>>> Why not?
>>>
>>> procedure FunctionBBB(atom param)
>>>   ?param
>>> end procedure
>>
>> <snip>
>>
>>> but no real error comes up as usual in Euphoria.
>>> <<Now why cant that happen with an invalid sequence arg?>> 
>>>
>>> Shouldnt there be an error message or something?

<big snip>

> Yes, the function (procedure) gets declared beforehand of course.
> The strange thing happens when you try to call a procedure with
> "return ProcedureName()"
> as the procedure never gets called, and you dont even see that
> warning you were talking about until you stop debugging
> (from trace mode).

You did not mention before that you were using trace mode.

With your both routines in the intended order, and using trace mode,
we have:

----------=----------=----------=----------=---------
with trace
trace(1)

procedure FunctionBBB(atom param)
   ?param
end procedure

function FunctionAAA()
   atom param
   param=1
   return FunctionBBB(param)
end function

FunctionAAA()
----------=----------=----------=----------=---------


> Now i know what to look for, but before i found that i didnt
> know what was causing the problem, so i thought i would
> mention it so it could raise an error in 2.5 perhaps.

Running my code above, exw.exe 2.4 says:
   Syntax error - expected to see an expression, not a procedure
      return FunctionBBB(param)
                       ^

So there _is_ an error message.


You wrote:
| try to call a procedure with
| "return ProcedureName()"
| as the procedure never gets called

This is neither true nor false, but it depends.
If the statement "return ProcedureName()" is inside a _function_ (as in
your code), then Eu _does_ try to call "ProcedureName()", and correctly
raises an error, because the correct syntax is "return <expression>",
and the name of a procedure is not a valid expression.


If "return ProcedureName()" is inside a _procedure_, then these are
actually _two_ statements. We better write:
   return
   ProcedureName()

That's the same for Euphoria, but I think humans so can better see the
difference between this and "return <expression>", as used in functions.


Therefore again I guess -- as Pete and me did before, but you neither
confirmed nor contradicted -- that the code you posted is _not_ the
code, that you used in your program.

_If_ you actually used "procedure FunctionAAA()" instead of
"function FunctionAAA()" then I see what you mean.

AFAIK warnings are _never_ shown until the end of the program (CMIIW).
Your point is, that inside a procedure
   return
   ProcedureName()
should raise an error rather than a warning, right?

Best regards,
   Juergen

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