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List:       kfm-devel
Subject:    Re: what's the return value of kjs-functions that appear to be void?
From:       Harri Porten <porten () trolltech ! com>
Date:       2001-07-28 13:29:41
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On Sat, 28 Jul 2001, Tobias Anton wrote:

> for the following patch, we're not sure about the result of the function:
> 
>  @@ -1074,8 +1074,9 @@ Completion WindowFunc::tryExecute(const
>     case Focus:
>  -    result = Undefined();
>  -    // TODO
>  +    if (widget)
>  +               widget->setActiveWindow();
>  +    return Completion(Normal);
>       break;
> 
> should it rather be Undefined()?
>  +    result = Undefined();
> and later:
>   return Completion(ReturnValue, result);

Yes. Assuming focus() doesn't return anything.

> What's the difference in the meaning of:
> Completion(Normal);
> and:
> Completion(ReturnValue, Undefined());

The first denotes leaving a function body without a return, break,
continue or throw statement. The later should be used when you want to
mimmick a simple return; (or return undefined;) statement.
The completion type is checked after a statement is executed and can lead
to e.g. abortion of execution or a different reaction on using a function
as constructor via 'new'.
The difference between a *undefined* ReturnValue completion or a Normal
completion is not so big, though.

> If the first is the Case, it would need to be changed in manymany places in 
> kjs_window and probably elsewhere.

Where for example ? Note that completions are only used in ::execute()
functions (tryExecute() here). get() and put() just return simple values
or Undefined() if none.

Harri.

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