This pragma reflects early attempts to incorporate Unicode into perl andhas since been superseded. It breaks encapsulation (i.e. it exposes theinnards of how the perl executable currently happens to store a string),and use of this module for anything other than debugging purposes isstrongly discouraged. If you feel that the functions here within might beuseful for your application, this possibly indicates a mismatch betweenyour mental model of Perl Unicode and the current reality. In that case,you may wish to read some of the perl Unicode documentation:perluniintro, perlunitut, perlunifaq and perlunicode.

SYNOPSIS

 use bytes;
  ... chr(...);   # or bytes::chr
  ... index(...); # or bytes::index
  ... length(...); # or bytes::length
  ... ord(...);   # or bytes::ord
  ... rindex(...); # or bytes::rindex
  ... substr(...); # or bytes::substr
  no bytes;

DESCRIPTION

The use bytes pragma disables character semantics for the rest of thelexical scope in which it appears. no bytes can be used to reversethe effect of use bytes within the current lexical scope.

Perl normally assumes character semantics in the presence of characterdata (i.e. data that has come from a source that has been marked asbeing of a particular character encoding). When use bytes is ineffect, the encoding is temporarily ignored, and each string is treatedas a series of bytes.

As an example, when Perl sees $x = chr(400), it encodes the characterin UTF-8 and stores it in $x. Then it is marked as character data, so,for instance, length $x returns 1. However, in the scope of thebytes pragma, $x is treated as a series of bytes - the bytes that makeup the UTF8 encoding - and length $x returns 2:

 $x = chr(400);
  print "Length is ", length $x, "\n"; # "Length is 1"
  printf "Contents are %vd\n", $x; # "Contents are 400"
  { 
  use bytes; # or "require bytes; bytes::length()"
  print "Length is ", length $x, "\n"; # "Length is 2"
  printf "Contents are %vd\n", $x; # "Contents are 198.144"
  }

chr(), ord(), substr(), index() and rindex() behave similarly.

For more on the implications and differences between charactersemantics and byte semantics, see perluniintro and perlunicode.

LIMITATIONS

bytes::substr() does not work as an lvalue().

Perl pragma to force byte semantics rather than character semantics

Daftar Isi

NAME

NOTICE

SYNOPSIS

DESCRIPTION

LIMITATIONS

SEE ALSO