Re: [gawk-devel] changing regex lib

[Paul Eggert]

Bruno Haible wrote:


> Therefore I would rewrite the comment
>
> /* Convert the byte B to the corresponding wide character.  In a
>     unibyte locale, treat B as itself.  In a multibyte locale, return
>     WEOF if B is an encoding error.  */
>
> to
>
> /* Convert the byte B to a value that bounds the iteration through a
>     character range.
>     In a unibyte locale, we use a bit set based on byte values, therefore
>     return B itself.  Note! This may be != btowc (B).
>     In a multibyte locale, we use comparison of wide characters, therefore
>     return the wide character corresponding to B, or WEOF if B is invalid.  */

Hmm, well, both comments are pretty confusing to me. However, the first one is 
less confusing, at least to me: it says that the function does X, and then that 
in a special case the function does Y (which contradicts X), and then that in 
another special case the function does Z (which also contradicts X). Although 
this sort of wording is not strictly logical, it is pretty routine in comments 
and not that hard to follow.

Rather than spend much time worring about this little comment, it'd probably be 
more helpful to document the intended behavior of rational ranges. As I 
understand it, Arnold wants them to use byte values in unibyte locales and wide 
character values in multibyte locales, and this intent is worth mentioning 
somewhere central, particularly since there are multiple places in the code 
where it is not implemented properly.