NAME
    Encode::Escape - Perl extension for Encodings of various escape
    sequences

SYNOPSIS
      use Encode::Escape;

      $escaped_ascii = "Perl\\tPathologically Eclectic Rubbish Lister\\n";
      $ascii = decode 'ascii-escape', $escaped_ascii;
  
      # Now, $ascii is equivalent to 
      # double quote string "Perl\tPathologically Eclectic Rubbish Lister\n"

      $escaped_unicode = "Perl \\x{041F}\\x{0435}\\x{0440}\\x{043B} \\x{D384}" 
      $string = decode 'unicode-escape', $escaped_unicode;

      # Now, $string is equvialent to 
      # double quote string "Perl \x{041F}\x{0435}\x{0440}\x{043B} \x{D384}" 

    It may looks non-sense. Here's another case.

    If you have a text data file 'ascii-escape.txt'. It contains a line:

      Perl\tPathologically Eclectic Rubbish Lister\n

    And you want to use it as if it were a normal double quote string in
    source code. Try this:

      open(FILE, 'ascii-escape.txt');
      while(<FILE>) {
        chomp;
        print decode 'ascii-escape', $_;
      }

DESCRIPTION
    Encode::Escape module is a wrapper class for encodings of escape
    sequences.

    It is NOT for an escape-based encoding (eg. ISO-2022-JP). It is for
    encoding/decoding escape sequences, generally used in source codes.

    Many programming languages, markup languages, and typesetting languages
    provide methods for encoding special (or functional) characters and
    non-keyboard symbols in the form of escape sequence. That's what I
    concern.

    For example, Encode::Escape::Unicode converts (encodes) Unicode
    characters into escape sequences representing it: "\x{AC00}" to the
    first Hangul syllable Ka, "\x{042F}" to Cyrillic capital letter Ya, etc.

    Yes, you're right. There already exist many modules. See String::Escape,
    Unicode::Escape, TeX::Encode, HTML::Mason::Escape,
    Template::Plugin::XML::Escape, URI::Escape, etc.

    But for some reason I need to do it in a different way. There is more
    than one way to do it! After that, I asked myself if this module is
    useful. May be not except for me. At this time, Zhuangzi reminds me that
    "the useless has its use".

  Escape Sequences
   Character Escape Codes
    ASCII defines 128 characters: 33 non-printing control characters (0x00
    -- 0x1f, 0x7f) and 95 printable characters (0x20 -- 0x7e).

    Character Escape Codes in C programming language provide a method to
    express control characters, using only printable ones. These are
    accepted by Perl and many other languages.

     CEC    HEX     Description
     ---    ----    --------------
     \0     00      Null character
     \a     07      Bell
     \b     08      Backspace
     \t     09      Horizontal Tab
     \n     0a      Line feed
     \v     0b      Vertical Tab
     \f     0c      Form feed
     \r     0d      Carriage return

    Programming languages provide escape sequences for printable characters,
    which have significant meaning in that language. Otherwise, it would be
    harder to print them literally.

     ESC    HEX     Description
     ---    ----    ---------------
     \"     22      double quote 
     \\     52      backslash

    Refer to ASCII, Escape character, Escape sequence at
    <http://en.wikipedia.org>, for more details.

   Perl Escape Sequences
    Perl use backslash as an escape character.

    These work in normal strings and regular expressions except \b.

     ESC       Description
     ---       --------------------------
     \a        Alarm (beep)
     \b        Backspace
     \e        Escape
     \f        Formfeed
     \n        Newline
     \r        Carriage return
     \t        Tab
     \037      Any octal ASCII value
     \x7f      Any hexadecimal ASCII value
     \x{263a}  A wide hexadecimal value
     \cx       Control-x
     \N{name}  name is a name for the Unicode character (use charnames)
 
    The following escape sequences are available in constructs that
    interpolate.

     \l        Lowercase next character
     \u        Titlecase next character
     \L        Lowercase until \E
     \U        Uppercase until \E
     \E        End case modification
 
    In regular expresssions:

     \b        An assetion, not backspace, except in a character class
     \Q        Disable pattern metacharacters until \E

    Unlike C and other languages, Perl has no \v escape sequence for the
    vertical tab (VT - ASCII 11).

    For constructs that do interpolate, variable begining with "$" or "@"
    are interpolated.

     \$        Dollar Sign
     \@        Ampersand
     \"        Print double quotes
     \         Escape next character if know otherwise print

    See perlerref, perlop

   Python Escape Sequences
     \newline   Ignored
     \\         Backslash (\)
     \'         Single quote (')
     \"         Double quote (")
     \a         ASCII Bell (BEL)
     \b         ASCII Backspace (BA)
     \f         ASCII Formfeed (FF)
     \n         ASCII Linefeed (LF)
     \N{name}   Character named 'name' in the Unicode database
     \r         ASCII Carriage Return (CR)
     \t         ASCII Horizontal Tab (TAB)
     \uxxxx     Character with 16-bit hex value xxxx (Unicode only)
     \Uxxxxxxxx Character with 32-bit hex value xxxxxxxx (Unicode only)
     \v         ASCII Vertical Tab (VT)
     \ooo       Character with octal value ooo
     \xhh       Character with hex value hh

    See <http://docs.python.org/ref/strings.html>

    Unicode escape sequences in the form of "\u"*xxxx* are used in Java,
    Python, C#, JavaScript. Unicode::Escape module implements it.

   LaTeX Escapes
    TeX::Encode implements encodings of LaTeX escapes. It converts (encodes)
    utf8 string to LaTeX escapes.

SEE ALSO
The useless has its use
    Hui Tzu said to Chuang Tzu, "Your words are useless!"

    Chuang Tzu said, "A man has to understand the useless before you can
    talk to him about the useful. The earth is certainly vast and broad,
    though a man uses no more of it than the area he puts his feet on. If,
    however, you were to dig away all the earth from around his feet until
    you reached the Yellow Springs, then would the man still be able to make
    use of it?"

    "No, it would be useless," said Hui Tzu.

    "It is obvious, then," said Chuang Tzu, "that the useless has its use."

AUTHOR
    You Hyun Jo, <you at cpan dot org>

COPYRIGHT AND LICENSE
    Copyright (C) 2007 by You Hyun Jo

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself, either Perl version 5.8.8 or, at
    your option, any later version of Perl 5 you may have available.

