[% setvar title C<\v> for Vertical Tab %]

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\v for Vertical Tab


  Maintainer: Nicholas Clark <nick@talking.bollo.cx>
  Date: 26 Sep 2000
  Last Modified: 30 Sep 2000
  Mailing List: perl6-language@perl.org
  Number: 327
  Version: 3
  Status: Frozen


Reissued on perl6-language@perl.org - I goofed the list. So far no comments on it.

Summarised discussion and changed status to frozen


Very little comment was made. Russ Allbery notes

	The last time I used a vertical tab intentionally and for some
	productive purpose was about 1984.

but states that this isn't an objection to the RFC.


perl5 includes all of C's escapes except \v (vertical tab). Treating \v the same as \a \b \e \f \h \r \t would remove a special case.


man perl says:

       Perl combines (in the author's opinion, anyway) some of
       the best features of C, sed, awk, and sh, so people
       familiar with those languages should have little
       difficulty with it. 

However, lack of \v represents a special case for a C programmer to learn. \v isn't used for anything else in double quoted strings, nor is it used in regular expressions, so it won't require removal of an existing feature to add it. Currently a \v in a double quoted strings will be treated as v, with a warning about unknown escape issued if warnings are in force.

Vertical tab was also omitted from the range of characters considered whitespace by \s in regular expressions.

This RFC proposes


Shouldn't be hard. Here are patches for perl 5.7.0

To be strict the perl5 to perl6 converter would need to

It might be considered acceptable to omit either or both conversions if the number of programs that would break were negligible.


perlop manpage for interpolation

perlre manpage for \s and \S