static void _RunFromFA()
{
var expr = RegexExpression.Parse("(0*11*0[01]*)");
var fa = expr.ToFA <string>();
fa.IsAccepting = true; // modify the expression by changing the FSM
var x = new CharFA <string>();
var y = new CharFA <string>();
var z = new CharFA <string>(true);
x.InputTransitions.Add('a', y);
y.InputTransitions.Add('b', y);
y.InputTransitions.Add('c', z);
fa = x;
var test = "[A-Z_a-z][0-9A-Z_a-z]*";
//test = "ab*c";
test = "(foo)*bar";
fa = RegexExpression.Parse(test).ToFA <string>();
fa.RenderToFile(@"..\..\..\test_expr_nfa.jpg");
var ffa = fa.ToDfa();
ffa.RenderToFile(@"..\..\..\test_expr.jpg");
expr = RegexExpression.FromFA(fa);
Console.WriteLine(expr);
fa.RenderToFile(@"..\..\..\test_nfa.jpg");
var dfa = fa.ToDfa();
dfa.RenderToFile(@"..\..\..\test.jpg");
}
static void _RunDom()
{
var test = "(ABC|DEF)*";
var dom = RegexExpression.Parse(test);
Console.WriteLine(dom.ToString());
var rep = dom as RegexRepeatExpression;
rep.MinOccurs = 1;
Console.WriteLine(dom.ToString());
dom.ToFA("Accept");
Console.WriteLine();
}
static void Main()
{
var sw = Stopwatch.StartNew();
var a = RegexExpression.Parse(@"a.+a").ToFA <string>();
Console.WriteLine(sw.ElapsedMilliseconds);
a.RenderToFile("tmp.png");
// _BuildArticleImages() // requires GraphViz
// _RunCompiledLexCodeGen()
/*_RunLexer();
* _RunMatch();
* _RunDom();
* // the following require GraphViz
* _RunStress();
* _RunStress2();*/
}
static void _RunStress()
{
// C# keywords
const string cskw = "abstract|add|as|ascending|async|await|base|bool|break|byte|case|catch|char|checked|class|const|continue|decimal|default|delegate|descending|do|double|dynamic|else|enum|equals|explicit|extern|false|finally|fixed|float|for|foreach|get|global|goto|if|implicit|int|interface|internal|is|lock|long|namespace|new|null|object|operator|out|override|params|partial|private|protected|public|readonly|ref|remove|return|sbyte|sealed|set|short|sizeof|stackalloc|static|string|struct|switch|this|throw|true|try|typeof|uint|ulong|unchecked|unsafe|ushort|using|var|virtual|void|volatile|while|yield";
var expr = RegexExpression.Parse(cskw);
var fa = expr.ToFA("");
Console.WriteLine("C# keyword NFA has {0} states.", fa.FillClosure().Count);
Console.WriteLine("Reducing C# keywords");
// very expensive in this case
fa = fa.Reduce(new _ConsoleProgress());
Console.WriteLine();
Console.WriteLine("C# keyword DFA has {0} states.", fa.FillClosure().Count);
var dopt = new CharFA <string> .DotGraphOptions();
dopt.Dpi = 150; // make the image smaller
Console.WriteLine("Rendering stress.jpg");
fa.RenderToFile(@"..\..\..\stress.jpg", dopt);
}
static void _BuildArticleImages()
{
// this generates the figures used in the code project article
// at https://www.codeproject.com/Articles/5251476/How-to-Build-a-Regex-Engine-in-Csharp
var litA = CharFA <string> .Literal("ABC", "Accept");
litA.RenderToFile(@"..\..\..\literal.jpg");
var litAa = CharFA <string> .CaseInsensitive(litA, "Accept");
litAa.RenderToFile(@"..\..\..\literal_ci.jpg");
var opt = CharFA <string> .Optional(litA, "Accept");
opt.RenderToFile(@"..\..\..\optional.jpg");
var litB = CharFA <string> .Literal("DEF");
var or = CharFA <string> .Or(new CharFA <string>[] { litA, litB }, "Accept");
or.RenderToFile(@"..\..\..\or.jpg");
var set = CharFA <string> .Set("ABC", "Accept");
set.RenderToFile(@"..\..\..\set.jpg");
var loop = CharFA <string> .Repeat(litA, 1, -1, "Accept");
loop.RenderToFile(@"..\..\..\repeat.jpg");
var concat = CharFA <string> .Concat(new CharFA <string>[] { litA, litB }, "Accept");
concat.RenderToFile(@"..\..\..\concat.jpg");
var foobar = CharFA <string> .Or(new CharFA <string>[] { CharFA <string> .Literal("foo"), CharFA <string> .Literal("bar") }, "Accept");
foobar.RenderToFile(@"..\..\..\foobar_nfa.jpg");
var rfoobar = foobar.Reduce();
rfoobar.RenderToFile(@"..\..\..\foobar.jpg");
var lfoobar = CharFA <string> .Repeat(foobar, 1, -1, "Accept");
lfoobar.RenderToFile(@"..\..\..\foobar_loop_nfa.jpg");
var rlfoobar = lfoobar.Reduce();
rlfoobar.RenderToFile(@"..\..\..\foobar_loop.jpg");
var digits = CharFA <string> .Repeat(
CharFA <string> .Set("0123456789"),
1, -1
, "Digits");
var word = CharFA <string> .Repeat(
CharFA <string> .Set(new CharRange[] { new CharRange('A', 'Z'), new CharRange('a', 'z') }),
1, -1
, "Word");
var whitespace = CharFA <string> .Repeat(
CharFA <string> .Set(" \t\r\n\v\f"),
1, -1
, "Whitespace");
var lexer = CharFA <string> .ToLexer(digits, word, whitespace);
lexer.RenderToFile(@"..\..\..\lexer.jpg");
var dopt = new CharFA <string> .DotGraphOptions();
dopt.DebugSourceNfa = lexer;
var dlexer = lexer.ToDfa();
dlexer.RenderToFile(@"..\..\..\dlexer.jpg", dopt
);
dlexer.RenderToFile(@"..\..\..\dlexer2.jpg");
var dom = RegexExpression.Parse("(ABC|DEF)+");
var fa = dom.ToFA("Accept");
fa.RenderToFile(@"..\..\..\ABCorDEFloop.jpg");
}
public SpecflowStepInfo Create(string classFullName, string methodName, GherkinStepKind stepKind, string pattern)
{
CharFA <string> regexForPartialMatch;
try
{
regexForPartialMatch = RegexExpression.Parse(pattern).ToFA <string>();
}
catch (Exception)
{
regexForPartialMatch = null;
}
Regex regex;
try
{
var fullMatchPattern = pattern;
if (!fullMatchPattern.StartsWith("^"))
{
fullMatchPattern = "^" + fullMatchPattern;
}
if (!fullMatchPattern.EndsWith("$"))
{
fullMatchPattern += "$";
}
regex = new Regex(fullMatchPattern, RegexOptions.Compiled, TimeSpan.FromSeconds(2));
}
catch (ArgumentException)
{
regex = null;
}
var regexesPerCapture = new List <Regex>();
var partialPattern = new StringBuilder();
var error = false;
foreach (var(type, text, _) in _stepPatternUtil.TokenizeStepPattern(pattern))
{
switch (type)
{
case StepPatternUtil.StepPatternTokenType.Text:
partialPattern.Append(text);
break;
case StepPatternUtil.StepPatternTokenType.Capture:
var captureText = text;
if (text == ".+")
{
captureText = ".+?";
}
else if (text == ".*")
{
captureText = ".*?";
}
partialPattern.Append('(').Append(captureText).Append(")");
try
{
regexesPerCapture.Add(new Regex("^" + partialPattern + "(?:(?:[ \"\\)])|$)", RegexOptions.Compiled));
}
catch (ArgumentException)
{
error = true;
}
break;
default:
throw new ArgumentOutOfRangeException();
}
if (error)
{
break;
}
}
return(new SpecflowStepInfo(classFullName, methodName, stepKind, pattern, regex, regexForPartialMatch, regexesPerCapture));
}