public Regex Parse(string regularExpression)
{
var grammar = new RegexGrammar();
var parseEngine = new ParseEngine(grammar, new ParseEngineOptions(optimizeRightRecursion: true));
var parseRunner = new ParseRunner(parseEngine, regularExpression);
while (!parseRunner.EndOfStream())
{
if (!parseRunner.Read())
{
throw new Exception(
$"Unable to parse regular expression. Error at position {parseRunner.Position}.");
}
}
if (!parseEngine.IsAccepted())
{
throw new Exception(
$"Error parsing regular expression. Error at position {parseRunner.Position}");
}
var parseForest = parseEngine.GetParseForestRootNode();
var parseTree = new InternalTreeNode(
parseForest as IInternalForestNode,
new SelectFirstChildDisambiguationAlgorithm());
var regexVisitor = new RegexVisitor();
parseTree.Accept(regexVisitor);
return(regexVisitor.Regex);
}
#pragma warning disable CC0091 // Use static method
public EbnfDefinition Parse(string ebnf)
{
var grammar = new EbnfGrammar();
var parseEngine = new ParseEngine(
grammar,
new ParseEngineOptions(
optimizeRightRecursion: true,
loggingEnabled: false));
var parseRunner = new ParseRunner(parseEngine, ebnf);
while (!parseRunner.EndOfStream())
{
if (!parseRunner.Read())
{
throw new Exception(
$"Unable to parse Ebnf. Error at line {parseRunner.Line}, column {parseRunner.Column}.");
}
}
if (!parseEngine.IsAccepted())
{
throw new Exception(
$"Ebnf parse not accepted. Error at line {parseRunner.Line}, column {parseRunner.Column}.");
}
var parseForest = parseEngine.GetParseForestRootNode();
var parseTree = new InternalTreeNode(
parseForest as IInternalForestNode,
new SelectFirstChildDisambiguationAlgorithm());
var ebnfVisitor = new EbnfVisitor();
parseTree.Accept(ebnfVisitor);
return(ebnfVisitor.Definition);
}
public static void Main(string[] args)
{
string grammarText = LoadFromResource(nameof(DefaultNamespaceName), "Grammar", "syntax5.ebnf");
//string input = File.ReadAllText("/etc/apache2/httpd.conf", Encoding.UTF8);
string input = "1 1";
var definition = new EbnfParser().Parse(grammarText);
var grammar = new EbnfGrammarGenerator().Generate(definition);
var parseEngine = new ParseEngine(grammar);
var parseRunner = new ParseRunner(parseEngine, input);
var recognized = false;
var errorPosition = 0;
while (!parseRunner.EndOfStream())
{
recognized = parseRunner.Read();
if (!recognized)
{
errorPosition = parseRunner.Position;
break;
}
}
var accepted = false;
if (recognized)
{
accepted = parseRunner.ParseEngine.IsAccepted();
if (!accepted)
{
errorPosition = parseRunner.Position;
}
}
Console.WriteLine($"Recognized: {recognized}, Accepted: {accepted}");
if (!recognized || !accepted)
{
Console.Error.WriteLine($"Error at position {errorPosition}");
}
// get the parse forest root from the parse engine
var parseForestRoot = parseEngine.GetParseForestRootNode();
// create a internal tree node and supply the disambiguation algorithm for tree traversal.
var parseTree = new InternalTreeNode(
parseForestRoot,
new SelectFirstChildDisambiguationAlgorithm());
Console.WriteLine(parseTree.ToString());
}
public void ParseEngineShouldDisambiguateFollowingOperatorPresidence()
{
var input = "2*3+5*7";
var parseTester = new ParseTester(new ExpressionGrammar());
parseTester.RunParse(input);
var forest = parseTester.ParseEngine.GetParseForestRootNode();
var tree = new InternalTreeNode(forest);
// ((2*3)+(5*7))
// (E, 0, 7) = (E, 0, 5) ('*', 5, 6) (E, 6, 7)
// (E, 0, 5) = (E, 0, 3) ('+', 3, 4) (E, 4, 5)
// (E, 0, 3) = (E, 0, 1) ('*', 1, 2) (E, 2, 3)
// (E, 0, 1) = ('2', 0, 1)
// (E, 2, 3) = ('3', 2, 3)
// (E, 4, 5) = ('5', 4, 5)
// (E, 6, 7) = ('7', 6, 7)
Assert.Inconclusive();
}
private static InternalTreeNode GetTreeNode(Grammar grammar, string input)
{
var parseEngine = new ParseEngine(grammar);
var parseRunner = new ParseRunner(parseEngine, input);
while (!parseRunner.EndOfStream())
{
Assert.IsTrue(parseRunner.Read());
}
Assert.IsTrue(parseEngine.IsAccepted());
var parseForest = parseEngine.GetParseForestRootNode();
Assert.IsNotNull(parseForest);
var internalNode = parseForest;
var treeNode = new InternalTreeNode(internalNode);
return(treeNode);
}
private static InternalTreeNode GetTreeNode(IGrammar grammar, string input)
{
var parseEngine = new ParseEngine(grammar);
var parseRunner = new ParseRunner(parseEngine, input);
while (!parseRunner.EndOfStream())
{
Assert.IsTrue(parseRunner.Read());
}
Assert.IsTrue(parseEngine.IsAccepted());
var parseForest = parseEngine.GetParseForestRootNode();
Assert.IsTrue(parseForest is IInternalForestNode);
var internalNode = parseForest as IInternalForestNode;
var disambiguationAlgorithm = new SelectFirstChildDisambiguationAlgorithm();
var treeNode = new InternalTreeNode(internalNode, disambiguationAlgorithm);
return(treeNode);
}
