Re: [Xen-devel] [PATCH RFC v2 06/13] libxl: permit declaration after statement

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Stefano Stabellini writes ("Re: [Xen-devel] [PATCH RFC v2 06/13] libxl: permit 
declaration after statement"):
> I think it would make sense to add to the CODING_STYLE that variable
> declarations shouldn't be mixed with code, unless part of a macro or an
> alloca-like construct.

I think this is a silly rule.  In my proposed commit message I
advanced three reasons for allowing declaration after statement:

> >  * It allows variables to be more often initialised as they are
> >    declared, thus reducing the occurrence of uninitialised variable
> >    errors.
> > 
> >  * Certain alloca-like constructs (arrays allocated at runtime on the
> >    stack) can more often be written without a spurious { } block.
> >    Such blocks are confusing to read.
> >
> >  * It makes it easier to write and use macros which declare and
> >    initialise formulaic variables and do other function setup code,
> >    because there is no need to worry that such macros might be
> >    incompatible with each other or have strict ordering constraints.

Of these the first two improvements would be banned by your proposed
coding style rule.

I don't understand what the harm is in allowing declarations, with
initialisation, freely mixed with code.

Ian.

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