syntax errors

syntax errors

[André Coelho]

Hey...if the compiler can check syntax errors...why can't it fixed them?


thanks


andre coelho

Re: syntax errors

[Andrew Pinski]

On Tue, May 10, 2022 at 3:19 PM André Coelho via Gcc <gcc@gcc.gnu.org> wrote:
>
> Hey...if the compiler can check syntax errors...why can't it fixed them?

In some cases it does recommend ways of fixing it. But not all syntax
errors are fixable.
Also not all syntax errors might be the wrong behavior vs what the user wanted.

Thanks,
Andrew Pinski



>
>
> thanks
>
>
> andre coelho
>

Re: syntax errors

[Mohamed Atef]

Because the fixed code may output results that you don't want.

int x 5;

Should it be int x = 5; or int x5;
The parsing operation is very hard and takes some time. There is a method
called Global correction to implement a compiler that changes the code but
besides the reason above it's too costly to implement.

Thanks
Mohamed

في الأربعاء، ١١ مايو، ٢٠٢٢ ١٢:٢٠ ص André Coelho via Gcc <gcc@gcc.gnu.org>
كتب:

> Hey...if the compiler can check syntax errors...why can't it fixed them?
>
>
> thanks
>
>
> andre coelho
>
>

Re: syntax errors

[Jonathan Wakely]

On Thu, 3 Jan 2019 at 17:03, Daniel Marjamäki
<daniel.marjamaki@gmail.com> wrote:
>
> Thank you for the quick reply.
>
> > how about "stray %qs token"?
>
> I will change.
>
> > I wonder how much we want to special-case this. Are you thinking about
> > the case where there's a stray symbol in the code (perhaps due to a
> > stray keypress, or unfinished manual edits)?
>
> At the moment I only think about ) } ]
>
> I would like to focus on only those 3 to start with. but it sounds
> good to prepare for more stray tokens later.

It doesn't scale to write a custom diagnostic for every invalid input
character in every context.

Re: syntax errors

[Daniel Marjamäki]

Thank you for the quick reply.

> how about "stray %qs token"?

I will change.

> I wonder how much we want to special-case this. Are you thinking about
> the case where there's a stray symbol in the code (perhaps due to a
> stray keypress, or unfinished manual edits)?

At the moment I only think about ) } ]

I would like to focus on only those 3 to start with. but it sounds
good to prepare for more stray tokens later.

> if (c_parser_next_token_is_meaningless_p (parser))
>   complain_about_stray_token (parser);
> else
>   ...

sure!

> It might make sense to emit a fix-it hint suggesting the removal of the
> stray token.

It is 50% chance that the closing paranthesis should be removed. Maybe
there is a missing "(".

Maybe the error message should indicate that.. something like "either
there is missing "(" or this ")" is a stray token".

Best regards,
Daniel Marjamäki