Re: [musl] [PATCH] complex: fix comment in cacosh

[Szabolcs Nagy <nsz@port70.net>]

* Rich Felker <dalias@libc.org> [2024-03-10 17:19:06 -0400]:

> On Sun, Mar 10, 2024 at 09:00:40PM +0100, Szabolcs Nagy wrote:
> > The principal experssions defining acosh and acos are such that
> > 
> >   acosh(z) = +-i acos(z)
> > 
> > where the + is only true on the Im(z)>0 half of the complex plane
> > (and partly on Im(z)==0 depending on number representation).
> > 
> > fix the comment without expanding on the details.
> > ---
> >  src/complex/cacosh.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/complex/cacosh.c b/src/complex/cacosh.c
> > index 76127f75..586328ce 100644
> > --- a/src/complex/cacosh.c
> > +++ b/src/complex/cacosh.c
> > @@ -1,6 +1,6 @@
> >  #include "complex_impl.h"
> >  
> > -/* acosh(z) = i acos(z) */
> > +/* acosh(z) = +-i acos(z) */
> >  
> >  double complex cacosh(double complex z)
> >  {
> 
> I'm fine with taking this patch as-is, but it naturally raises a
> question: should it instead be:
> 
> -/* acosh(z) = i acos(z) */
> +/* acosh(z) = ±i acos(z) */
> 
> IOW, should we use non-ascii characters in comments like this? My

fine with me,

for me it's easier to type +- on the keyboard though.

> leaning would be yes, especially since it may be needed to properly
> attribute an algorithm or something where the only alternative is
> misspelling someone's name or leaving it out entirely.
> 
> Really the only consideration for not doing this would be if it
> actively breaks compiling in some environments, but I don't think
> that's the case.
> 
> Rich