private Statement ParseStatement()
{
Statement parsedStatement;
if (currentToken == listTokens.Count)
{
ExceptionHandler("statement was expected before end of file");
}
if (listTokens[currentToken].Equals("print"))
{
currentToken++;
Write _Write = new Write();
_Write.Expression = ParseExpression();
parsedStatement = _Write;
}
else if (listTokens[currentToken].Equals("var"))
{
currentToken++;
DeclareVariable _DeclareVariable = new DeclareVariable();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_DeclareVariable.Identifier = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("variable name was expected after 'var'");
}
currentToken++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("= sign was expected after 'var identifier'");
}
currentToken++;
_DeclareVariable.Expression = ParseExpression();
parsedStatement = _DeclareVariable;
}
else if (listTokens[currentToken].Equals("call"))
{
currentToken++;
CallFunction _CallFunction = new CallFunction();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_CallFunction.FunctionName = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("function name is expected after 'call'");
}
currentToken++;
_CallFunction.Parameter1 = ParseExpression();
//index++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.Comma.ToString())
{
ExceptionHandler("',' sign was expected after first parameter");
}
currentToken++;
_CallFunction.Parameter2 = ParseExpression();
//index++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.Comma.ToString())
{
ExceptionHandler("',' sign was expected after second parameter");
}
currentToken++;
_CallFunction.Parameter3 = ParseExpression();
//index++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.Terminator.ToString())
{
ExceptionHandler("';' sign was expected after third parameter");
}
parsedStatement = _CallFunction;
}
else if (listTokens[currentToken].Equals("string") || listTokens[currentToken].Equals("numeric") || listTokens[currentToken].Equals("void"))
{
DeclareFunction _DeclareFunction = new DeclareFunction();
_DeclareFunction.ReturnType = listTokens[currentToken].ToString();
currentToken++;
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_DeclareFunction.FunctionName = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("function name is expected after return type");
}
currentToken++;
if (listTokens[currentToken].Equals("var"))
{
currentToken++;
DeclareVariable _DeclareVariable = new DeclareVariable();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_DeclareVariable.Identifier = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("variable name was expected after 'var'");
}
currentToken++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("= sign was expected after 'var identifier'");
}
currentToken++;
_DeclareVariable.Expression = ParseExpression();
_DeclareFunction.Parameter1 = _DeclareVariable;
}
currentToken++;
if (listTokens[currentToken].Equals("var"))
{
currentToken++;
DeclareVariable _DeclareVariable = new DeclareVariable();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_DeclareVariable.Identifier = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("variable name was expected after 'var'");
}
currentToken++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("= sign was expected after 'var identifier'");
}
currentToken++;
_DeclareVariable.Expression = ParseExpression();
_DeclareFunction.Parameter2 = _DeclareVariable;
}
currentToken++;
if (listTokens[currentToken].Equals("var"))
{
currentToken++;
DeclareVariable _DeclareVariable = new DeclareVariable();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_DeclareVariable.Identifier = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("variable name was expected after 'var'");
}
currentToken++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("= sign was expected after 'var identifier'");
}
currentToken++;
_DeclareVariable.Expression = ParseExpression();
_DeclareFunction.Parameter3 = _DeclareVariable;
}
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("begin"))
{
ExceptionHandler("expected 'begin' after input parameters");
}
currentToken++;
_DeclareFunction.Body = ParseStatement();
parsedStatement = _DeclareFunction;
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("endfunc"))
{
ExceptionHandler("unterminated function', 'endfunc' expected at the end");
}
currentToken++;
}
else if (listTokens[currentToken].Equals("read"))
{
currentToken++;
ReadInput _ReadInput = new ReadInput();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_ReadInput.Identifier = (string)listTokens[currentToken++];
parsedStatement = _ReadInput;
}
else
{
ExceptionHandler("variable name is expected after 'read'");
parsedStatement = null;
}
}
// IfThenElse ifThenElse = new IfThenElse();
// RelationalExpression relExpr = new RelationalExpression();
// relExpr.Left = ParseExpression();
// if (listTokens[index] == Scanner.EqualTo)
// relExpr.Operand = RelationalOperands.EqualTo;
// else if (listTokens[index] == Scanner.LessThan)
// relExpr.Operand = RelationalOperands.LessThan;
// else if (listTokens[index] == Scanner.GreaterThan)
// relExpr.Operand = RelationalOperands.GreaterThan;
// else
// {
// ExceptionHandler("expected relational operand");
// }
// index++;
// relExpr.Right = ParseExpression();
// ifThenElse.If = relExpr;
// index++;
// ifThenElse.Then = ParseStatement();
// parsedStatement = ifThenElse;
// //index++;
else if (listTokens[this.currentToken].Equals("while"))
{
currentToken++;
While _while = new While();
_while.LeftExpression = ParseExpression();
if (listTokens[currentToken].ToString() == Lexer.Tokens.EqualTo.ToString())
{
_while.Operand = RelationalOperands.EqualTo;
}
else if (listTokens[currentToken].ToString() == Lexer.Tokens.LessThan.ToString())
{
_while.Operand = RelationalOperands.LessThan;
}
else if (listTokens[currentToken].ToString() == Lexer.Tokens.GreaterThan.ToString())
{
_while.Operand = RelationalOperands.GreaterThan;
}
currentToken++;
_while.RightExpression = ParseExpression();
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("do"))
{
ExceptionHandler("expected 'do' after while");
}
currentToken++;
_while.Body = ParseStatement();
parsedStatement = _while;
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("endwhile"))
{
ExceptionHandler("unterminated 'while', endwhile expected at the end");
}
currentToken++;
}
else if (listTokens[this.currentToken].Equals("if"))
{
currentToken++;
IfThen _IfThen = new IfThen();
_IfThen.LeftExpression = ParseExpression();
if (listTokens[currentToken].ToString() == Lexer.Tokens.EqualTo.ToString())
{
_IfThen.Operand = RelationalOperands.EqualTo;
}
else if (listTokens[currentToken].ToString() == Lexer.Tokens.LessThan.ToString())
{
_IfThen.Operand = RelationalOperands.LessThan;
}
else if (listTokens[currentToken].ToString() == Lexer.Tokens.GreaterThan.ToString())
{
_IfThen.Operand = RelationalOperands.GreaterThan;
}
currentToken++;
_IfThen.RightExpression = ParseExpression();
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("then"))
{
ExceptionHandler("expected 'then' after if");
}
currentToken++;
_IfThen.ThenBody = ParseStatement();
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("else"))
{
ExceptionHandler("'else' is expected");
}
currentToken++;
_IfThen.ElseBody = ParseStatement();
parsedStatement = _IfThen;
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("endif"))
{
ExceptionHandler("unterminated 'if', endif expected at the end");
}
currentToken++;
}
else if (listTokens[currentToken].Equals("for"))
{
currentToken++;
For _For = new For();
if (currentToken < listTokens.Count && listTokens[currentToken] is string)
{
_For.Identifier = (string)listTokens[currentToken];
}
else
{
ExceptionHandler("expected identifier after 'for'");
}
currentToken++;
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("for missing '='");
}
currentToken++;
_For.From = ParseExpression();
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("to"))
{
ExceptionHandler("expected 'to' after for");
}
currentToken++;
_For.To = ParseExpression();
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("do"))
{
ExceptionHandler("expected 'do' after from expression in for loop");
}
currentToken++;
_For.Body = ParseStatement();
parsedStatement = _For;
if (currentToken == listTokens.Count || !listTokens[currentToken].Equals("end"))
{
ExceptionHandler("unterminated 'for' loop body");
}
currentToken++;
}
else if (listTokens[currentToken] is string)
{
// assignment
Assignment _Assignment = new Assignment();
_Assignment.Identifier = (string)listTokens[currentToken++];
if (currentToken == listTokens.Count || listTokens[currentToken].ToString() != Lexer.Tokens.EqualTo.ToString())
{
ExceptionHandler("expected '='");
}
currentToken++;
_Assignment.Expression = ParseExpression();
parsedStatement = _Assignment;
}
else
{
ExceptionHandler("parse error at token " + currentToken + ": " + listTokens[currentToken]);
parsedStatement = null;
}
if (currentToken < listTokens.Count && listTokens[currentToken].ToString() == Lexer.Tokens.Terminator.ToString())
{
currentToken++;
if (currentToken < listTokens.Count && !listTokens[currentToken].Equals("end") &&
!listTokens[currentToken].Equals("else") && !listTokens[currentToken].Equals("endif") &&
!listTokens[currentToken].Equals("endwhile") && !listTokens[currentToken].Equals("endfunc"))
{
StatementSequence sequence = new StatementSequence();
sequence.Left = parsedStatement;
sequence.Right = ParseStatement();
parsedStatement = sequence;
}
}
return(parsedStatement);
}
public void GenerateStatementMethod(Statement _statement)
{
#region Statement
if (_statement is StatementSequence)
{
StatementSequence _StatementSequence = (StatementSequence)_statement;
GenerateStatementMethod(_StatementSequence.Left);
GenerateStatementMethod(_StatementSequence.Right);
}
#endregion
#region Declare Variable
else if (_statement is DeclareVariable)
{
// declare a variable in symbol table
DeclareVariable declare = (DeclareVariable)_statement;
tblIdentifier[declare.Identifier] =
_ILMethod.DeclareLocal(GetExpressionTypeMethod(declare.Expression));
// set the initial value
Assignment assign = new Assignment();
assign.Identifier = declare.Identifier;
assign.Expression = declare.Expression;
GenerateStatementMethod(assign);
}
#endregion
#region Assignment
else if (_statement is Assignment)
{
Assignment assign = (Assignment)_statement;
GenerateExpressionMethod(assign.Expression, GetExpressionTypeMethod(assign.Expression));
if (GetExpressionTypeMethod(assign.Expression) == typeof(ArithmaticExpression))
{
SaveIdentifierMethod(assign.Identifier, typeof(Int32));
}
else
{
SaveIdentifierMethod(assign.Identifier,
GetExpressionTypeMethod(assign.Expression));
}
}
#endregion
else if (_statement is DeclareFunction)
{
DeclareFunction _DeclareFunction = (DeclareFunction)_statement;
string strFunctionName = _DeclareFunction.FunctionName;
Type ParameterType1 = GetExpressionTypeMethod(_DeclareFunction.Parameter1.Expression);
Type ParameterType2 = GetExpressionTypeMethod(_DeclareFunction.Parameter2.Expression);
Type ParameterType3 = GetExpressionTypeMethod(_DeclareFunction.Parameter3.Expression);
Type[] InputParameters = { ParameterType1, ParameterType2, ParameterType3 };
Type ReturnType = typeof(void);
if (_DeclareFunction.ReturnType == "void")
{
ReturnType = typeof(void);
}
else if (_DeclareFunction.ReturnType == "string")
{
ReturnType = typeof(string);
}
else if (_DeclareFunction.ReturnType == "numeric")
{
ReturnType = typeof(int);
}
//FieldBuilder Parameter1 = _typeBuilder.DefineField(_DeclareFunction.Parameter1.Identifier, ParameterType1, FieldAttributes.Private);
//FieldBuilder Parameter2 = _typeBuilder.DefineField(_DeclareFunction.Parameter2.Identifier, ParameterType2, FieldAttributes.Private);
//FieldBuilder Parameter3 = _typeBuilder.DefineField(_DeclareFunction.Parameter3.Identifier, ParameterType3, FieldAttributes.Private);
MethodBuilder NewMethod =
_typeBuilder.DefineMethod
(strFunctionName,
MethodAttributes.Static,
ReturnType,
InputParameters);
//ParameterBuilder poolRefBuilder = NewMethod.DefineParameter(1, ParameterAttributes.In, _DeclareFunction.Parameter1.Identifier);
_ILMethod = NewMethod.GetILGenerator();
//tblArguments[_DeclareFunction.Parameter0.Identifier] = _ILMethod.
tblArguments[_DeclareFunction.Parameter1.Identifier] = _ILMethod.DeclareLocal(ParameterType1);
GenerateExpressionMethod(_DeclareFunction.Parameter1.Expression, ParameterType1);
//_ILMethod.Emit(OpCodes.Starg, 0);
tblArguments[_DeclareFunction.Parameter1.Identifier] = _ILMethod.DeclareLocal(ParameterType2);
GenerateExpressionMethod(_DeclareFunction.Parameter1.Expression, ParameterType2);
//_ILMethod.Emit(OpCodes.Starg, 1);
tblArguments[_DeclareFunction.Parameter2.Identifier] = _ILMethod.DeclareLocal(ParameterType3);
GenerateExpressionMethod(_DeclareFunction.Parameter2.Expression, ParameterType3);
//_ILMethod.Emit(OpCodes.Starg, 2);
//GenerateStatementMethod(_DeclareFunction.Body);
//_ILMethod.Emit(OpCodes.Ret);
}
#region write-read
else if (_statement is Write)
{
// for print keyword, call .net method for printscreen
GenerateExpressionMethod(((Write)_statement).Expression,
typeof(string));
_ILMethod.Emit(OpCodes.Call,
typeof(System.Console).GetMethod("WriteLine",
new System.Type[] { typeof(string) }));
}
else if (_statement is ReadInput)
{
// call the readline method and parse input method
_ILMethod.Emit(OpCodes.Call,
typeof(System.Console).GetMethod("ReadLine",
BindingFlags.Public | BindingFlags.Static,
null, new System.Type[] { }, null));
_ILMethod.Emit(OpCodes.Call,
typeof(int).GetMethod("Parse",
BindingFlags.Public | BindingFlags.Static,
null, new System.Type[] { typeof(string) }, null));
// store the input value in local builder
SaveIdentifierMethod(((ReadInput)_statement).Identifier, typeof(int));
}
#endregion
#region While
else if (_statement is While)
{
While _while = (While)_statement;
Label lblTest = _ILMethod.DefineLabel();
Label lblEnd = _ILMethod.DefineLabel();
if (_while.Operand == RelationalOperands.GreaterThan)
{
_ILMethod.MarkLabel(lblTest);
GenerateExpressionMethod(_while.LeftExpression, typeof(int));
GenerateExpressionMethod(_while.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Cgt);
_ILMethod.Emit(OpCodes.Brfalse, lblEnd);
GenerateStatementMethod(_while.Body);
_ILMethod.Emit(OpCodes.Br, lblTest);
_ILMethod.MarkLabel(lblEnd);
}
else if (_while.Operand == RelationalOperands.EqualTo)
{
_ILMethod.MarkLabel(lblTest);
GenerateExpressionMethod(_while.LeftExpression, typeof(int));
GenerateExpressionMethod(_while.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Ceq);
_ILMethod.Emit(OpCodes.Brfalse, lblEnd);
GenerateStatementMethod(_while.Body);
_ILMethod.Emit(OpCodes.Br, lblTest);
_ILMethod.MarkLabel(lblEnd);
}
else if (_while.Operand == RelationalOperands.LessThan)
{
_ILMethod.MarkLabel(lblTest);
GenerateExpressionMethod(_while.LeftExpression, typeof(int));
GenerateExpressionMethod(_while.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Clt);
_ILMethod.Emit(OpCodes.Brfalse, lblEnd);
GenerateStatementMethod(_while.Body);
_ILMethod.Emit(OpCodes.Br, lblTest);
_ILMethod.MarkLabel(lblEnd);
}
}
#endregion
#region If-Then
else if (_statement is IfThen)
{
IfThen ifThen = (IfThen)_statement;
Label lblElse = _ILMethod.DefineLabel();
Label lblEnd = _ILMethod.DefineLabel();
#region GreaterThan
if (ifThen.Operand == RelationalOperands.GreaterThan)
{
GenerateExpressionMethod(ifThen.LeftExpression, typeof(int));
GenerateExpressionMethod(ifThen.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Cgt);
_ILMethod.Emit(OpCodes.Brfalse, lblElse);
GenerateStatementMethod(ifThen.ThenBody);
_ILMethod.Emit(OpCodes.Br, lblEnd);
_ILMethod.MarkLabel(lblElse);
GenerateStatementMethod(ifThen.ElseBody);
_ILMethod.MarkLabel(lblEnd);
}
#endregion
#region EqualTo
else if (ifThen.Operand == RelationalOperands.EqualTo)
{
GenerateExpressionMethod(ifThen.LeftExpression, typeof(int));
GenerateExpressionMethod(ifThen.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Ceq);
_ILMethod.Emit(OpCodes.Brfalse, lblElse);
GenerateStatementMethod(ifThen.ThenBody);
_ILMethod.Emit(OpCodes.Br, lblEnd);
_ILMethod.MarkLabel(lblElse);
GenerateStatementMethod(ifThen.ElseBody);
_ILMethod.MarkLabel(lblEnd);
}
#endregion
#region LessThan
else if (ifThen.Operand == RelationalOperands.LessThan)
{
GenerateExpressionMethod(ifThen.LeftExpression, typeof(int));
GenerateExpressionMethod(ifThen.RightExpression, typeof(int));
_ILMethod.Emit(OpCodes.Clt);
_ILMethod.Emit(OpCodes.Brfalse, lblElse);
GenerateStatementMethod(ifThen.ThenBody);
_ILMethod.Emit(OpCodes.Br, lblEnd);
_ILMethod.MarkLabel(lblElse);
GenerateStatementMethod(ifThen.ElseBody);
_ILMethod.MarkLabel(lblEnd);
}
#endregion
}
#endregion
#region for
else if (_statement is For)
{
For forLoop = (For)_statement;
Assignment assign = new Assignment();
assign.Identifier = forLoop.Identifier;
assign.Expression = forLoop.From;
GenerateStatementMethod(assign);
Label test = _ILMethod.DefineLabel();
_ILMethod.Emit(OpCodes.Br, test);
Label body = _ILMethod.DefineLabel();
_ILMethod.MarkLabel(body);
GenerateStatementMethod(forLoop.Body);
_ILMethod.Emit(OpCodes.Ldloc, tblIdentifier[forLoop.Identifier]);
_ILMethod.Emit(OpCodes.Ldc_I4, 1);
_ILMethod.Emit(OpCodes.Add);
SaveIdentifierMethod(forLoop.Identifier, typeof(int));
_ILMethod.MarkLabel(test);
_ILMethod.Emit(OpCodes.Ldloc, tblIdentifier[forLoop.Identifier]);
GenerateExpressionMethod(forLoop.To, typeof(int));
_ILMethod.Emit(OpCodes.Blt, body);
}
#endregion
else
{
ExceptionHandler("unable to generate " + _statement.GetType().Name);
}
}