/// <summary>
/// Adds an operand to the expression.
/// </summary>
/// <param name="token">Token to add as an operand</param>
/// <param name="addToFirst">Whether to add operand as first operand</param>
public void AddOperand(Token token, bool addToFirst)
{
if ( addToFirst )
{
FirstOperand = token;
}
else
{
SecondOperand = token;
}
}
/// <summary>
/// Adds a new semantic error
/// </summary>
/// <param name="token">Token</param>
/// <param name="message">Message</param>
public static void AddSemanticError(Token token, string message)
{
if ( token != null )
{
SemanticErrors.Add(
new Error(Lines[token.Line - 1], token.Line, token.StartColumn, message));
}
else
{
SemanticErrors.Add(
new Error(Lines[Lines.Count - 1], Lines.Count, Lines[Lines.Count - 1].Length, message));
}
}
/// <summary>
/// Adds a syntax error to the list of errors
/// </summary>
/// <param name="token">Current token</param>
/// <param name="expectedLexeme">Expected lexeme</param>
/// <param name="useDefault">Use default message: "Was expecting {expectedLexeme}."</param>
private void AddSyntaxError(Token token, string expectedLexeme, bool useDefault = true)
{
if (token == null)
{
_syntaxErrors.Add(
new Error(Scanner.Lines[Scanner.Lines.Count - 1], Scanner.Lines.Count - 1, Scanner.Lines[Scanner.Lines.Count - 1].Length, String.Format("Unexpected end of file, was expecting {0}.", expectedLexeme)));
return;
}
if (useDefault)
{
_syntaxErrors.Add(
new Error(Scanner.Lines[token.Line - 1], token.Line, token.StartColumn, String.Format("Was expecting {0}.", expectedLexeme)));
}
else
{
_syntaxErrors.Add(
new Error(Scanner.Lines[token.Line - 1], token.Line, token.StartColumn, expectedLexeme));
}
}
/// <summary>
/// Checks the token for null reference and correct lexeme
/// </summary>
/// <param name="token">Current token</param>
/// <param name="lexeme">Lexeme expected</param>
/// <returns>True if ok</returns>
public static bool CheckToken(Token token, string lexeme)
{
return token != null && token.Lexeme == lexeme;
}
/// <summary>
/// Extracts string value from a terminal token or variable.
/// Basicly this is ToString() for tokenterminal and variables of type t
/// </summary>
/// <param name="token">Terminal or variable token</param>
/// <returns>Value</returns>
private static string ExtractString(Token token)
{
var tokenTerminal = token as TokenTerminal<string>;
if ( tokenTerminal != null )
{
return tokenTerminal.Value;
}
var tokenIdentifier = token as TokenIdentifier;
if ( tokenIdentifier != null )
{
var s = Statement.GetVariable(tokenIdentifier.Identifier) as VariableType<string>;
if ( s != null )
{
return s.Value;
}
var i = Statement.GetVariable(tokenIdentifier.Identifier) as VariableType<int>;
if ( i != null )
{
return i.Value.ToString();
}
var b = Statement.GetVariable(tokenIdentifier.Identifier) as VariableType<bool>;
if ( b != null )
{
return b.Value.ToString().ToLower();
}
}
try
{
return ExtractInt(token).ToString();
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
try
{
return ExtractBool(token).ToString().ToLower();
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
Statements.AddSemanticError(token, "Was expecting a string value.");
throw new AbstractSyntaxTreeException("");
}
/// <summary>
/// Extracts integer value from terminal token or from variable token
/// </summary>
/// <param name="token">Terminal or variable token</param>
/// <returns>Value</returns>
private static int ExtractInt(Token token)
{
var tokenTerminal = token as TokenTerminal<int>;
if ( tokenTerminal != null )
{
return tokenTerminal.Value;
}
var tokenIdentifier = token as TokenIdentifier;
if ( tokenIdentifier != null )
{
var variable = Statement.GetVariable(tokenIdentifier.Identifier) as VariableType<int>;
if ( variable != null )
{
return variable.Value;
}
}
Statements.AddSemanticError(token, "Was expecting an int value.");
throw new AbstractSyntaxTreeException("");
}
/// <summary>
/// Compares two string values
/// </summary>
/// <param name="token"> </param>
/// <param name="firstValue">First value</param>
/// <param name="op">Operator</param>
/// <param name="secondValue">Second value</param>
/// <returns>Comparison</returns>
private static bool Compare(Token token, string firstValue, string op, string secondValue)
{
switch ( op )
{
case Operators.Equal:
return firstValue == secondValue;
case Operators.NotEqual:
return firstValue != secondValue;
}
Statements.AddSemanticError(token, "Can't compare values string and string with operator " + op);
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Compares two integer values
/// </summary>
/// <param name="token"> </param>
/// <param name="firstValue">First value</param>
/// <param name="op">Operator</param>
/// <param name="secondValue">Second value</param>
/// <returns>Comparison</returns>
private static bool Compare(Token token, int firstValue, string op, int secondValue)
{
switch (op)
{
case Operators.Equal:
return firstValue == secondValue;
case Operators.NotEqual:
return firstValue != secondValue;
case Operators.GreaterThan:
return firstValue > secondValue;
case Operators.GreaterOrEqualThan:
return firstValue >= secondValue;
case Operators.LesserThan:
return firstValue < secondValue;
case Operators.LesserOrEqualThan:
return firstValue <= secondValue;
}
Statements.AddSemanticError(token, "Can't compare values int and int with operator " + op);
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Calculates boolean value from expression and operand
/// </summary>
/// <param name="first">First expression</param>
/// <param name="op">Operator</param>
/// <param name="second">Second operand</param>
/// <returns>Result</returns>
private static bool CalculateBool(Expression first, string op, Token second)
{
try
{
var b1 = first.EvaluateBool();
var b2 = ExtractBool(second);
return Calculate(first.GetFirstNotNullToken(), b1, op, b2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
try
{
var i1 = first.EvaluateInt();
var i2 = ExtractInt(second);
return Compare(first.GetFirstNotNullToken(), i1, op, i2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
try
{
var s1 = first.EvaluateString();
var s2 = ExtractString(second);
return Compare(first.GetFirstNotNullToken(), s1, op, s2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
Statements.AddSemanticError(first.GetFirstNotNullToken(), "Could not evaluate value.");
throw new AbstractSyntaxTreeCalculateException("Couldn't evaluate.");
}
/// <summary>
/// Calculates boolean value from two operands
/// </summary>
/// <param name="first">First operand</param>
/// <param name="op">Operator</param>
/// <param name="second">Second operand</param>
/// <returns>Result</returns>
private static bool CalculateBool(Token first, string op, Token second)
{
try
{
var b1 = ExtractBool(first);
var b2 = ExtractBool(second);
return Calculate(first, b1, op, b2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
try
{
var i1 = ExtractInt(first);
var i2 = ExtractInt(second);
return Compare(first, i1, op, i2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
try
{
var s1 = ExtractString(first);
var s2 = ExtractString(second);
return Compare(first, s1, op, s2);
}
catch ( AbstractSyntaxTreeException )
{
Statements.DeleteLastAddedError();
}
Statements.AddSemanticError(first, "Could not evaluate value.");
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Calculates string value from two operands
/// </summary>
/// <param name="token"> </param>
/// <param name="firstValue">First value</param>
/// <param name="op">Operator</param>
/// <param name="secondValue">Second value</param>
/// <returns>Result</returns>
private static string Calculate(Token token, string firstValue, string op, string secondValue)
{
if (op == Operators.Plus)
{
return firstValue + secondValue;
}
Statements.AddSemanticError(token, String.Format("Can't apply operator '{0}' to a string operation.", op));
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Calculates integer value from two operands
/// </summary>
/// <param name="token"> </param>
/// <param name="firstValue">First value</param>
/// <param name="op">Operator</param>
/// <param name="secondValue">Second value</param>
/// <returns>Result</returns>
private static int Calculate(Token token, int firstValue, string op, int secondValue)
{
switch ( op )
{
case Operators.Plus:
return firstValue + secondValue;
case Operators.Minus:
return firstValue - secondValue;
case Operators.Multiply:
return firstValue * secondValue;
case Operators.Divide:
return firstValue / secondValue;
}
Statements.AddSemanticError(token, String.Format("Can't apply operator '{0}' to operands 'int' and int'.", op));
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Calculates boolean value from two operands
/// </summary>
/// <param name="token"> </param>
/// <param name="firstValue">First value</param>
/// <param name="op">Operator</param>
/// <param name="secondValue">Second value</param>
/// <returns>Result</returns>
private static bool Calculate(Token token, bool firstValue, string op, bool secondValue)
{
switch (op)
{
case Operators.Equal:
return firstValue == secondValue;
case Operators.NotEqual:
return firstValue != secondValue;
case Operators.And:
return firstValue != secondValue;
}
Statements.AddSemanticError(token, String.Format("Can't apply operator '{0}' to operands 'bool' and 'bool'.", op));
throw new AbstractSyntaxTreeCalculateException("");
}
/// <summary>
/// Produces tokens for the parser.
/// </summary>
/// <param name="lines">Source code</param>
/// <returns>Tokens</returns>
public List<Token> Tokenize(List<string> lines)
{
if ( lines == null )
{
throw new ScannerException("Lines were null");
}
Lines = lines;
var tokens = new List<Token>();
for (_row = 0; _row < lines.Count; _row++)
{
_column = 0;
var line = lines[_row];
while (_column < line.Length)
{
var stop = SkipWhiteSpace(line);
if (stop)
{
break;
}
if ( _column < line.Length - 1 && line[_column] == '/' && line[_column + 1] == '*' ) // Multiline comment
{
SkipMultilineComment(lines);
continue;
}
if (_column < line.Length - 1 && line[_column] == '/' && line[_column + 1] == '/') // line comment
{
break;
}
Token token;
if ( (token = CreateTypeToken(line)) != null )
{
tokens.Add(token);
_previousToken = token;
continue;
}
if ( (token = CreateReservedKeywordToken(line)) != null )
{
tokens.Add(token);
_previousToken = token;
continue;
}
if ( (token = CreateOperatorToken(line)) != null )
{
tokens.Add(token);
_previousToken = token;
continue;
}
if ( (token = CreateTerminalToken(line)) != null )
{
tokens.Add(token);
_previousToken = token;
continue;
}
if ( (token = CreateIdentifierToken(line)) != null )
{
tokens.Add(token);
_previousToken = token;
continue;
}
if ( (token = CreateErrorToken(line)) != null)
{
tokens.Add(token);
_previousToken = token;
}
}
}
return tokens;
}
/// <summary>
/// Creates a token if it matches the given symbol
/// </summary>
/// <param name="line">Current line</param>
/// <param name="symbol">Symbol to match</param>
/// <returns>Created token or null</returns>
private Token CreateToken(string line, string symbol)
{
// One can make this to work a lot faster, but this is nicer
try
{
if ( line.Substring(_column, symbol.Length) == symbol )
{
var token = new Token(_row, _column, symbol);
_column += symbol.Length;
return token;
}
}
catch (ArgumentOutOfRangeException)
{
}
return null;
}
