[svn:perl6-synopsis] r14370 - doc/trunk/design/syn Author: larry Date: Thu Apr 12 17:11:56 2007 New Revision: 14370 Modified:    doc/trunk/design/syn/S02.pod Log: Clarify the single-character backslash escapes, including \\c control forms. Note that \\c[ is not legal to mean \\c[ESCAPE] Modified: doc/trunk/design/syn/S02.pod ============================================================================== --- doc/trunk/design/syn/S02.pod	(original) +++ doc/trunk/design/syn/S02.pod	Thu Apr 12 17:11:56 2007 @@ -12,9 +12,9 @@      Maintainer: Larry Wall     Date: 10 Aug 2004 -  Last Modified: 16 Mar 2007 +  Last Modified: 12 Apr 2007    Number: 2 -  Version: 100 +  Version: 101    This document summarizes Apocalypse 2, which covers small-scale  lexical items and typological issues.  (These Synopses also contain @@ -2274,7 +2274,15 @@    Backslash sequences still interpolate, but there's no longer any C<\\v>  to mean I, whatever that is...  (C<\\v> now match vertical -whitespace in a regex.) +whitespace in a regex.)  Literal character representations are: + +    \\a          BELL +    \\b          BACKSPACE +    \\t          TAB +    \\n          LINE FEED +    \\f          FORM FEED +    \\r          CARRIAGE RETURN +    \\e          ESCAPE    =item *   @@ -2302,6 +2310,22 @@    [Note: none of the official Unicode character names contains comma.]   +(Within a regex you may also use C<\\C> to match a character that is +not the specified character.) + +If the character following C<\\c> or C<\\C> is not a left square bracket, +the single following character is turned into a control character by +the usual trick of XORing the 64 bit.  This allows C<\\c@> for NULL +and C<\\c?> for DELETE, but note that the ESCAPE character may not be +represented that way; it must be represented something like: + +    \\e +    \\c[ESCAPE] +    \\x1B +    \\o33 + +Obviously C<\\e> is preferred when brevity is needed. +  =item *    There are no barewords in PerlÂ 6.  An undeclared bare identifier will