public static void GenerateLexer(string inputFile, string outputFile)
{
var inputStream = new AntlrFileStream(inputFile);
var spreadsheetLexer = new LexerLexer(inputStream);
var commonTokenStream = new CommonTokenStream(spreadsheetLexer);
var lexerParser = new LexerParser(commonTokenStream);
var grammatixContext = lexerParser.grammatix();
var visitor = new LexerVisitor();
visitor.Visit(grammatixContext);
var tokens = visitor.TokenContainer.Tokens;
using (var writer = File.CreateText(outputFile))
{
writer.WriteLine("using System.IO;");
writer.WriteLine("using System.Text.RegularExpressions;");
writer.WriteLine("namespace Generated{");
writer.WriteLine("public enum Token{");
var hasSkip = false;
foreach (var(name, _) in tokens)
{
hasSkip |= name == "SKIP";
writer.WriteLine(name);
writer.WriteLine(",");
}
writer.WriteLine("EOF");
if (!hasSkip)
{
writer.WriteLine(",");
writer.WriteLine("SKIP");
}
writer.WriteLine("}");
writer.WriteLine("public class GeneratedLexer{");
writer.WriteLine("public string CurrentString { get; private set; }");
foreach (var(name, text) in tokens)
{
writer.WriteLine("private static readonly Regex " + name + "REGEX = new Regex(\"^\" + @\"" + text + "\");");
}
writer.WriteLine("private readonly string myInput;");
writer.WriteLine("private int myIndex;");
writer.WriteLine("public GeneratedLexer(string input){");
writer.WriteLine("myInput = input;");
writer.WriteLine("}");
writer.WriteLine("public Token NextToken(){");
foreach (var(name, _) in tokens)
{
if (name == "EPS" || name == "EOF")
{
throw new Exception($"Token name {name} reserved, choose another name.");
}
writer.WriteLine("if(" + name + "REGEX.IsMatch(myInput.Substring(myIndex))){");
writer.WriteLine("var match = " + name + "REGEX.Match(myInput.Substring(myIndex));");
writer.WriteLine("CurrentString = match.Value;");
writer.WriteLine("myIndex += match.Length;");
writer.WriteLine("return Token." + name + ";");
writer.WriteLine("}");
}
writer.WriteLine("if(myInput.Length == myIndex){");
writer.WriteLine("return Token.EOF;");
writer.WriteLine("}");
writer.WriteLine("throw new InvalidDataException();");
writer.WriteLine("}");
writer.WriteLine("}");
writer.WriteLine("}");
}
}
