Re: [PATCH 4/5] diff: use SWAP macro

["René Scharfe" <l.s.r@web.de>]

Am 30.01.2017 um 17:04 schrieb Johannes Schindelin:
> Hi René,
>
> On Sat, 28 Jan 2017, René Scharfe wrote:
>
>> Use the macro SWAP to exchange the value of pairs of variables instead
>> of swapping them manually with the help of a temporary variable.  The
>> resulting code is shorter and easier to read.
>>
>> The two cases were not transformed by the semantic patch swap.cocci
>> because it's extra careful and handles only cases where the types of all
>> variables are the same -- and here we swap two ints and use an unsigned
>> temporary variable for that.  Nevertheless the conversion is safe, as
>> the value range is preserved with and without the patch.
>
> One way to make this more obvious would be to change the type to signed
> first, and then transform (which then would catch these cases too,
> right?).

I'm not sure it would be more obvious, but it would certainly make the 
type change more explicit.  In diff-index.c we might even want to change 
the type of the swapped values from int to unsigned, which is more 
fitting for file modes.  In diff.c we'd need to add a separate variable, 
as tmp is shared with other (unsigned) swaps.

René