private static BaseLexerRule CreateRegexDfa(string pattern)
{
var regexParser = new RegexParser();
var regex = regexParser.Parse(pattern);
var regexCompiler = new RegexCompiler();
var dfa = regexCompiler.Compile(regex);
return new DfaLexerRule(dfa, pattern);
}
public void RegexToDfaShouldConvertCharacterRegexToDfa()
{
var pattern = "a";
var regex = new RegexParser().Parse(pattern);
var nfa = new ThompsonConstructionAlgorithm().Transform(regex);
var dfa = new SubsetConstructionAlgorithm().Transform(nfa);
Assert.IsNotNull(dfa);
var lexerRule = new DfaLexerRule(dfa, "a");
var lexeme = new DfaLexemeFactory().Create(lexerRule);
Assert.IsTrue(lexeme.Scan('a'));
}
public void RegexToDfaShouldConvertOptionalCharacterClassToDfa()
{
var pattern = @"[-+]?[0-9]";
var regex = new RegexParser().Parse(pattern);
var nfa = new ThompsonConstructionAlgorithm().Transform(regex);
var dfa = new SubsetConstructionAlgorithm().Transform(nfa);
Assert.IsNotNull(dfa);
Assert.AreEqual(3, dfa.Transitions.Count);
var lexerRule = new DfaLexerRule(dfa, pattern);
AssertLexerRuleMatches(lexerRule, "+0");
AssertLexerRuleMatches(lexerRule, "-1");
AssertLexerRuleMatches(lexerRule, "9");
}
private static INfa CreateNfa(string input)
{
var regex = new RegexParser().Parse(input);
return new ThompsonConstructionAlgorithm().Transform(regex);
}