-module(re_tuner).

-export([tune/1]).

% \s
tune("\\s") ->
    "[ \\t\\n\\r]";
% [^\s]
tune("[^\\s]") ->
    "[^ \\t\\n\\r]";

% \h
tune("\\h") ->
    "[\\x9,\\x20]";
% [^\h]
tune("[^\\h]") ->
    "[\\0-\\x8\\xA-\\x1F\\x21-x7F]";
	
% \v
tune("\\v") ->
    "[\\xA-\\xD]";
% [^\h]
tune("[^\\v]") ->
    "[\\0-\\x9\\xE-x7F]";	
	
% Posix [[:alnum:]]
tune("[[:alnum:]]") ->
    "[\\x30-\\x39\\x41-\\x5A\\x61-\\x7A]";
% Posix [[:^alnum:]]
tune("[[:^alnum:]]") ->
    "[\\0-\\x29\\x3A-\\x40\\x5B-\\x60\\x7B-\\x7F]";
	
% Posix [[:alpha:]]
tune("[[:alpha:]]") ->
    "[\\x41-\\x5A\\x61-\\x7A]";
% Posix [[:^alpha:]]
tune("[[:^alpha:]]") ->
    "[\\0-\\x40\\x5B-\\x60\\x7B-\\x7F]";
	
% Posix [[:lower:]]
tune("[[:lower:]]") ->
    "[\\x61-\\x7A]";
% Posix [[:^lower:]]
tune("[[:^lower:]]") ->
    "[\\0-\\x60\\x7B-\\x7F]";

% Posix [[:upper:]]
tune("[[:upper:]]") ->
    "[\\x41-\\x5A]";
tune("[[:^upper:]]") ->
    "[\\0-\\x40\\x5B-\\xF7]";
	
% Posix [[:digit:]]
tune("[[:digit:]]") ->
    "[\\x30-\\x39]";
tune("[[:^digit:]]") ->
    "[\\0-\\x29\\x3A-\\x7F]";

% Posix [[:graph:]]
tune("[[:graph:]]") ->
    "[\\x21-\\x7E]";	
tune("[[:^graph:]]") ->
    "[\\0-\\x20\\x7F]";

% Posix [[:print:]]
tune("[[:print:]]") ->
    "[\\x20-\\x7E]";	
tune("[[:^print:]]") ->
    "[\\0-\\x1F\\x7F]";	

% Posix [[:punct:]]
tune("[[:punct:]]") ->
    "[\\x21-\\x2F\\x3A-\\x40\\x5B-\\x60\\x7B-\\x7E]";	
tune("[[:^punct:]]") ->
    "[\\0-\\x20\\x30-\\x39\\x41-\\x5A\\x61-\\x7A\\x7F]";	

% Posix [[:space:]]
tune("[[:space:]]") ->
    "[\\x9-\\xD\\x20]";	
tune("[[:^space:]]") ->
    "[\\0-\\x8\\xE-\\x1F\\x21-\\x7F]";

% Posix [[:cntrl:]]
tune("[[:cntrl:]]") ->
    "[\\0-\\x1F]";	
tune("[[:^cntrl:]]") ->
    "[\\x20-\\x7F]";
	
% Posix [[:ascii:]]
tune("[[:ascii:]]") ->
    "[\\0-\\x7F]"	
	.