/// <summary>
/// Adds all of the rules associated with assignment 1
/// </summary>
/// <param name="lexer">Lexer that is going to be performing the analysis</param>
public static void AddLexerRules(Lexer.Lexer lexer)
{
lexer.AddRule(@"if\b",
s => new Token {Type = TokenType.If})
.AddRule(@"then\b",
s => new Token {Type = TokenType.Then})
.AddRule(@"while\b",
s => new Token {Type = TokenType.While})
.AddRule(@"do\b",
s => new Token {Type = TokenType.Do})
.AddRule(@"input\b",
s => new Token {Type = TokenType.Input})
.AddRule(@"else\b",
s => new Token {Type = TokenType.Else})
.AddRule(@"begin\b",
s => new Token {Type = TokenType.Begin})
.AddRule(@"end\b",
s => new Token {Type = TokenType.End})
.AddRule(@"write\b",
s => new Token {Type = TokenType.Write})
.AddRule(@"[a-zA-Z_][a-zA-Z0-9_]*",
s => new Token {Contents = s, Type = TokenType.Id})
.AddRule(@"[\d]+",
s => new Token {Contents = s, Type = TokenType.Num})
.AddRule(@"\+",
s => new Token {Type = TokenType.Add})
.AddRule(@":=",
s => new Token {Type = TokenType.Assign})
.AddRule(@"-",
s => new Token {Type = TokenType.Sub})
.AddRule(@"\*",
s => new Token {Type = TokenType.Mul})
.AddRule(@"/",
s => new Token {Type = TokenType.Div})
.AddRule(@"\(",
s => new Token {Type = TokenType.LPar})
.AddRule(@"\)",
s => new Token {Type = TokenType.RPar})
.AddRule(@";",
s => new Token {Type = TokenType.Semicolon});
}
private static void Main(string[] args)
{
// Loads input string from source file
var sourceString = GetSourceFileText(args);
// initializes lexer and RDP classes
var lexer = new Lexer.Lexer(Lexer.Lexer.LexerLoggingMode.None);
var rdp = new RecursiveDescentParser();
// adds rules to lexer and parser
RulesModule.AddLexerRules(lexer);
RulesModule.AddRdpRules(rdp);
try
{
Console.WriteLine("Parsing tokens from source...");
// parse tokens from source using lexer
ParseTokens(sourceString, lexer);
// generate AST from token list
Console.WriteLine("\n\nGenerating AST...");
Node rootNode = GenerateAst(rdp, lexer);
Console.WriteLine();
// generate AST visualization and compiled code
GenerateGraphvis(rootNode);
GenerateCompiledCode(rootNode);
Console.WriteLine("Success!");
}
catch (InvalidTokenException e)
{
// Handle token parsing issues
Console.WriteLine($"Parse Error: {e.Message}");
}
catch (UnexpectedTokenException e)
{
// unexpected token / syntax error
Console.WriteLine(e.Message);
}
}