On 02/06/2011 14:57, Ingo Schwarze wrote:
> Hi Ulrich,
>
> Ulrich Spörlein wrote on Thu, Jun 02, 2011 at 01:15:47PM +0200:
>> On Thu, 02.06.2011 at 12:54:56 +0300, Kristaps Dzonsons wrote:
>>> On 02/06/2011 12:28, Ulrich Spörlein wrote:
>
>>>> Hello,
>>>>
>>>> please consider doing the same as groff here, fixing ambiguities
>>>>
>>>> Before:
>>>>
>>>>        The atan2(), atan2f(), and atan2l() functions, if successful,
>>>>        return the arc tangent of y/x in the range [-n, +n] radians.
>>>>
>>>> After:
>>>>
>>>>        The atan2(), atan2f(), and atan2l() functions, if successful,
>>>>        return the arc tangent of y/x in the range [-pi, +pi] radians.
>>>>
>>>> Although 'n' might look a little like '??' we shouldn't replace random
>>>> letters for greek symbols that have different meaning.
>
>>> This is not something that groff agrees upon.  The stock groff on
>>> GNU/Linux returns `n' instead of `pi'.  Version: GNU troff (groff)
>>> version 1.21.  We've discussed this before, I think... the quick
>>> solution is to patch it downstream (chars.in).  I personally don't like
>>> the attenuation of /any/ Greek characters, as my own formulas end up
>>> confusing (those with both pi and n, for example).
>
>> I disagree on groff disagreeing
>>
>> FreeBSD base groff version 1.19.2: \*(Pi ->  pi
>> FreeBSD port groff version 1.21:   \*(Pi ->  pi
>> Ubuntu groff version 1.20.1:       \*(Pi ->  pi
>
> Oh that one, indeed.
>
> I fixed this here and just need to merge it to bsd.lv:
>
> http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/mandoc/predefs.in
> Revision 1.2
>
> Ulrich is talking about \*(Pi in -Tascii,
> Kristaps is talking about \(*p in -Tascii.
>
> What groff does with \*(Pi is
>   - "pi" in nroff mode (-Tascii)
>   - real pi glyph in troff mode (-Tps)
>
> Mandoc could do the same as long as it was handling predefined strings
> in the same way as character escape sequences.  Now that it handles
> predefined strings in the preprocessor, it cannot achieve this any
> longer.
>
> Hum.  I only realize now how serious that regression is from a
> theoretical point of view...
> Not sure what to do about this in general.

Ingo,

I don't think this is serious.  It's trivial to add bits that pass 
libroff the notion of whether it's troff (-Tascii) or nroff 
(-Teverythinglese).  In fact, we should be doing this anyway, which will 
allow us to respond to `.if n' in the Right Way.  Doubly in fact, 
enclosed is a patch for it.  Thoughts?  From here it's just a matter of 
mechanical bits to let this go to predef.in in some way, whether by 
having predef.in have `.if' clauses or whatever.

K.