/// <summary>
/// Given a regular expression, attempt to generate a string that would match it. This is a rather
/// simple implementation, so don't be shocked if it blows up on you in a spectacular fashion. It does
/// not handle ., *, unbound ranges such as {1,}, extensions such as (?=), character classes, some
/// abbreviations for characters classes, and nested parantheses. I told you it was simple. :) It's
/// also probably dog-slow, so you shouldn't use it. It will take a reg ex like this:
/// "^[A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]? {1,2}[0-9][ABD-HJLN-UW-Z]{2}$"
/// and generate a string like this: "U3V 3TP"
/// </summary>
/// <param name="reg"></param>
/// <returns></returns>
public static string Regexify(this string reg)
{
// Trim slashes:
reg = reg.Trim('/');
// Ditch the anchors
reg = Regex.Replace(reg, @"{^\/?\^?}", string.Empty, RegexOptions.Compiled);
reg = Regex.Replace(reg, @"{\$?\/?$}", string.Empty, RegexOptions.Compiled);
// All {2} become {2,2}
reg = Regex.Replace(reg, @"\{(\d+)\}", "{$1,$1}", RegexOptions.Compiled);
// All ? become {0,1}
reg = Regex.Replace(reg, @"\?", "{0,1}", RegexOptions.Compiled);
// [12]{1,2} becomes [12] or [12][12]
reg = reg.ExpandRanges();
// (12|34){1,2} becomes (12|34) or (12|34)(12|34)
reg = Regex.Replace(reg, @"(\([^\)]+\))\{(\d+),(\d+)\}", match =>
{
throw new NotImplementedException();
}, RegexOptions.Compiled);
// A{1,2} becomes A or AA or \d{3} becomes \d\d\d
reg = Regex.Replace(reg,
@"(\\?.)\{(\d+),(\d+)\}",
match =>
{
var toRepeat = match.Groups[1].Value;
var lowerBoundary = int.Parse(match.Groups[2].Value);
var upperBoundary = int.Parse(match.Groups[3].Value);
int[] intRange = new Range2 <int>(lowerBoundary, upperBoundary).AsArray();
var result = string.Concat(intRange.Sample().Times(_ => toRepeat));
return(result);
}, RegexOptions.Compiled);
// (this|that) becomes 'this' or 'that'
reg = ExpandOr(reg);
// All A-Z inside of [] become C (or X, or whatever)
reg = Regex.Replace(reg, @"\[([^\]]+)\]", match =>
{
var result = Regex.Replace(match.Value, @"(\w\-\w)", range =>
{
var parts = Regex.Split(range.Value, "-");
var charRange = new Range2 <char>(parts[0][0], parts[1][0]);
return($"{charRange.Sample()}");
});
return(result);
}, RegexOptions.Compiled);
// All [ABC] become B (or A or C)
reg = Regex.Replace(reg, @"\[([^\]]+)\]", match =>
{
var charRange = match.Groups[1].Value.ToCharArray();
return($"{charRange.Sample()}");
}, RegexOptions.Compiled);
reg = Regex.Replace(reg, Regex.Escape(@"\d"), _ => $"{Numbers.Sample()}", RegexOptions.Compiled);
reg = Regex.Replace(reg, Regex.Escape(@"\w"), _ => $"{Letters.Sample()}", RegexOptions.Compiled);
return(reg);
}
