Re: [Cpptool-develop] Progress on InlineTemp

[Baptiste L. <gai...@fr...>]

----- Original Message -----
From: "Andre Baresel" <and...@gm...>
To: "Baptiste Lepilleur" <gai...@fr...>
Sent: Friday, December 27, 2002 8:57 PM
Subject: Re: [Cpptool-develop] Progress on InlineTemp


> Baptiste Lepilleur wrote:
>
> >----- Original Message -----
> >From: "Andre Baresel" <and...@gm...>
> >To: "CppTool Mailing List" <Cpp...@li...>
> >Sent: Friday, December 27, 2002 11:38 AM
> >Subject: [Cpptool-develop] Progress on InlineTemp
> >
> >
> >
> >
> >>There're just two things that are left to be done for the InlineTemp
> >>refactoring.
> >>Both of them need an improvement in expression parsing I'm currently
> >>thinking
> >>about. The two things are:
> >>- detect assignments to a temporary variable
> >>
> >>
> >
> >Yes, we need that. Sven started something like that for the SplitTemp
> >refactoring. I'm not sure what the status of the code is though. Give a
look
> >to SplitTempRefactoring class.
> >
> Yep, I did this afternoon and found that it does only check the
> character the follows the occurence of a
> temporary variable. This is for the first ok, but it does not really
> work for the future.
> imagine the code : "if (temp == 0)" .. in this case we have no
> assignment ...
>
> >
> >
> >
> >>- find out if the initializer expression consists of one or more
> >>elements (in case
> >>   of more elements I need to add braces when inlining the expression)
> >>
> >>
> >
> >I don't get what you mean. Do you mean if the variable is initialized by
a
> >constructor ?
> >
> nope this will be detected as not allowed at the moment since it
> contains an identifier.
> However just two examples:
>
> int tmpTobeInlined = 3;
> expr = tmpTobeInlined * 5;
> ==> Here we have no problem just replacing the tmpToBeInlined by its
> initializer resulting in:
> expr = 3 * 5;
>
> But what about:
> int tmpTobeInlined = 3 + 3;
> expr = tmpTobeInlined * 5;
> ==> Here we have to add braces for the expression "3 + 3" resulting in:
> expr = (3 + 3) * 5;
>
> For that reason I'm currently adding allways braces which doesn't look
> very nice for most usecases I believe:
> expr = ( 3 ) * 5;
> With some Code-Rewriter that knowns about minimal placement of braces
> that would be no problem.
>
>    I was just thinking about an heuristic for the decision of placing
> braces:
>    Just check if any c++ operator occures in the blanked text of the
> initializer. If it does, I will place braces, if not
>    I leave it as it is.

Ok, I understand the issue better know. What would be need is:

1) Is the initializer expression 'atomic' (it is not a composite of
expression) ?
2) Does the expression need to be surrounded by braces when inlined in a
given expression? ( x = tmpTobeInlined; does not need braces, but x =
tmpTobeInlined * 2 need braces).

For now, I suggest letting the user decide if braces should be added. This
would be a parameter passed to the apply() method. May be add a simple
heuristic for a default value (should add braces if '-' or '+' is found in
the expression).

Baptiste.

>
> -- Andre