This and other RFCs are available on the web at http://dev.perl.org/rfc/ =head1 TITLE C<\v> for Vertical Tab =head1 VERSION Maintainer: Nicholas Clark <[EMAIL PROTECTED]> Date: 26 Sep 2000 Last Modified: 30 Sep 2000 Mailing List: [EMAIL PROTECTED] Number: 327 Version: 3 Status: Frozen =head1 CHANGES Reissued on [EMAIL PROTECTED] - I goofed the list. So far no comments on it. Summarised discussion and changed status to frozen =head1 DISCUSSION 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. =head1 ABSTRACT perl5 includes all of C's escapes except C<\v> (vertical tab). Treating C<\v> the same as C<\a> C<\b> C<\e> C<\f> C<\h> C<\r> C<\t> would remove a special case. =head1 DESCRIPTION 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 C<\v> represents a special case for a C programmer to learn. C<\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 C<\v> in a double quoted strings will be treated as C<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 C<\s> in regular expressions. This RFC proposes =over 4 =item 1 C<\v> becomes a recognised escape for a vertical tab in interpolated contexts (double quoted strings and regular expressions) =item 2 That vertical tab is moved from the C<\S> (non-whitespace) to C<\s> (whitespace) class in regular expressions. =back =head1 IMPLEMENTATION Shouldn't be hard. Here are patches for perl 5.7.0 =over 4 =item C<\v> --- toke.c.orig Fri Sep 15 04:14:57 2000 +++ toke.c Tue Sep 26 12:54:30 2000 @@ -469,7 +469,7 @@ for (t = s; !isSPACE(*t); t++) ; e = t; } - while (SPACE_OR_TAB(*e) || *e == '\r' || *e == '\f') + while (SPACE_OR_TAB(*e) || *e == '\r' || *e == '\f' || *e == '\v') e++; if (*e != '\n' && *e != '\0') return; /* false alarm */ @@ -1196,7 +1196,7 @@ : UTF; const char *leaveit = /* set of acceptably-backslashed characters */ PL_lex_inpat - ? "\\.^$@AGZdDwWsSbBpPXC+*?|()-nrtfeaxcz0123456789[{]} \t\n\r\f\v#" + ? "\\.^$@AGZdDwWsSbBpPXC+*?|()-nrtfveaxcz0123456789[{]} \t\n\r\f\v#" : ""; while (s < send || dorange) { @@ -1540,6 +1540,9 @@ case 'f': *d++ = '\f'; break; + case 'v': + *d++ = '\v'; + break; case 't': *d++ = '\t'; break; @@ -2700,7 +2703,7 @@ Perl_croak(aTHX_ "\t(Maybe you didn't strip carriage returns after a network transfer?)\n"); #endif - case ' ': case '\t': case '\f': case 013: + case ' ': case '\t': case '\f': case '\v': #ifdef MACOS_TRADITIONAL case '\312': #endif --- t/op/pat.t.orig Tue Aug 29 13:54:13 2000 +++ t/op/pat.t Tue Sep 26 12:56:36 2000 @@ -469,27 +469,27 @@ print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/i eq '(?i-xsm:\bv$)'; +print "not " unless qr/\b\y$/i eq '(?i-xsm:\by$)'; print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/s eq '(?s-xim:\bv$)'; +print "not " unless qr/\b\y$/s eq '(?s-xim:\by$)'; print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/m eq '(?m-xis:\bv$)'; +print "not " unless qr/\b\y$/m eq '(?m-xis:\by$)'; print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/x eq '(?x-ism:\bv$)'; +print "not " unless qr/\b\y$/x eq '(?x-ism:\by$)'; print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/xism eq '(?msix:\bv$)'; +print "not " unless qr/\b\y$/xism eq '(?msix:\by$)'; print "ok $test\n"; $test++; -print "not " unless qr/\b\v$/ eq '(?-xism:\bv$)'; +print "not " unless qr/\b\y$/ eq '(?-xism:\by$)'; print "ok $test\n"; $test++; =item C<\S> to C<\s> --- handy.h.orig Thu Sep 14 15:44:20 2000 +++ handy.h Tue Sep 26 13:04:30 2000 @@ -295,8 +295,9 @@ #define isIDFIRST(c) (isALPHA(c) || (c) == '_') #define isALPHA(c) (isUPPER(c) || isLOWER(c)) #define isSPACE(c) \ - ((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) =='\r' || (c) == '\f') -#define isPSXSPC(c) (isSPACE(c) || (c) == '\v') + ((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) =='\r' || (c) == '\f' \ + || (c) == '\v') +#define isPSXSPC(c) isSPACE(c) #define isBLANK(c) ((c) == ' ' || (c) == '\t') #define isDIGIT(c) ((c) >= '0' && (c) <= '9') #ifdef EBCDIC --- t/op/pat.t.orig Tue Aug 29 13:54:13 2000 +++ t/op/pat.t Tue Sep 26 14:27:14 2000 @@ -1064,15 +1064,14 @@ cr => "\r", lf => "\n", ff => "\f", -# The vertical tabulator seems miraculously be 12 both in ASCII and EBCDIC. - vt => chr(11), + vt => "\v", false => "space" ); my @space0 = sort grep { $space{$_} =~ /\s/ } keys %space; my @space1 = sort grep { $space{$_} =~ /[[:space:]]/ } keys %space; my @space2 = sort grep { $space{$_} =~ /[[:blank:]]/ } keys %space; -print "not " unless "@space0" eq "cr ff lf spc tab"; +print "not " unless "@space0" eq "cr ff lf spc tab vt"; print "ok $test\n"; $test++; =back To be strict the perl5 to perl6 converter would need to =over 4 =item * replace C<\v> with C<v> in interpolated strings. =item * replace C<\s> with C<[\t\n\r\f ]> and C<\S> with C<[^\t\n\r\f ]> in regular expressions. =back It might be considered acceptable to omit either or both conversions if the number of programs that would break were negligible. =head1 REFERENCES perlop manpage for interpolation perlre manpage for \s and \S
