Regexp description on http://www.digitalmars.com/ctg/regular.html says that:
\s matches a space
\S matches any character but a space
It's definitely not true in case of phobos regexp's. I found it after
frustrating experience when trying to match only spaces and tabs but not
\r and \n. It was not working as specs says - \r and \n was also matched!
Probably \s matches something like this: [\f\n\r\t\v\x85\p{Z}] - any
white-space character. What's more as I observed space character is taken
literally from regexp, so there is no need to have escape character for
space.
one of refs which I found on net: http://regexlib.com/cheatsheet.aspx