[Proj] Question on colon DMS format

[Gerald I. Evenden]

Maybe someone here is familiar with what I call the colon format for DMS 
display where degree-minute-seconds are in the from of DDD:MM:SS.SSS[NEWS]
or perhaps sign prefixed.

The quesion is: can only one colon be present such as for DDD:MM.MMM such as 
allowable in DMS as DDDdmm.mmm[']?

This is immaterial for proj_dms2rad as it accepts all of them but I was 
curious if users should be careful to exclude anything less then the two 
colon format for proj_rad2dms output format specification.

The first time I encountered the colon format was at the CERL Grass group in 
Illinois many, many years ago.  I see it occasionally elsewhere.

Also, is anyone familiar with any other DMS format?

PS: angle input in proj has also recognized r suffix as denoting radian input 
for many years.  I have also though of including rad but do not know how to 
designate such input since 'r' is already taken.  ;-(

An anecdotal aside: USGS FORTRAN GCTP once used (and maybe still does) 
a "packed" double precision variable dddmmss.sssssd00 (I may have 
misremembered the exact details but that was the basic essence).  But what 
was sooo horrible was that IBM's input formatter would ignore 0s replaced by 
blanks in the middle of the word such that 10 0 0.000000D00 was OK for 10 
degrees. BUT!! As you can imagine, that did not go over well for reading on 
any other processor where embedded blanks were verboten.  One off several 
reasons I did not have a very high opinion of GCTP.  PROJ was a rebellion 
against the evils of GCTP.

-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist