Scalar::Quote - Utility functions to quote Perl strings

  use Scalar::Quote ':short';
  $_=pack('c',rand 127) for (@a[0..1000]);
  $s1=join '', @a;
  $_=pack('c',rand 127) for (@b[0..1000]);
  $s2=join '', @b;
  $_=pack('c',rand 127) for (@c[0..40]);
  $s3=join '', @c;

  print "Q(\$s1)=",Q($s1),"\n";
  print "S(\$a)=",S($a),"\n";
  D($s3.$s1, $s3.$s2);
  print "$a is not the same as $b\n";
  print N(0), N(1), N(undef), N("hello"), "\n";

Several subrutines to quote scalars and spot differences between strings.

Mostly useful for debugging purposes.

quote_number($n)

N($n)

quote $n as a number.

quote($string)

Q($string)

returns the string conveniently enclosed in single or double quotes, escaping unprintable and quoting chars as required.

quote_start($string)

S($string)

quote_start($string, $length)

S($string, $length)

quote the beginning of $string.

quote_cut($str, $start, $len)

similar to substr($str, $start, $len) but adds a head or/and a tail to the substring stating how many chars have been left out.

str_diffix

returns the index where the two strings start to differ or -1 if they are equal.

str_diff($s1, $s2)

str_diff($s1, $s2, $start, $len)

D($s1, $s2)

D($s1, $s2, $start, $len)

str_diff compares two strings and creates quoted versions of them around the place where they start to differ.

  D($s1, $s2) and print "$a is not the same as $b\n";

In scalar context the quoted strings are stored in globals $a and $b on the caller package.

In list context the quoted strings are returned ($a and $b are untouched).

When both strings are equal, undef or the empty list is returned.

Optional arguments $start and $len allow to configure the length of the quoting. $start is the location to start the quote *after* the differences begin, so it should be a negative number.

Nothing by default.

:quote

exports quote, quote_start, quote_cut and quote_number

:diff

exports str_diffix and str_diff subrutines.

: short

exports Q, S, N and D.

Salvador Fandiño, <sfandino@yahoo.com>

Copyright 2002-2006 by Salvador Fandiño

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.