private void ConstantsDeclaration()
{
if (tokenList.GetCurrentTokenType() == Enums.TokenType.constsym)
{
do
{
tokenList.NextToken();
Symbol newSymbol = new Symbol();
newSymbol.type = Enums.TokenType.constsym;
newSymbol.level = currentLevel;
if (tokenList.GetCurrentTokenType() != Enums.TokenType.identsym)
{
error = Enums.GeneratorError.RESERVED_NOT_FOLLOWED_BY_IDENT;
return;
}
newSymbol.name = tokenList.GetCurrentToken().lexeme;
tokenList.NextToken();
if (tokenList.GetCurrentTokenType() != Enums.TokenType.eqsym)
{
error = Enums.GeneratorError.IDENT_NOT_FOLLOWED_BY_NUM;
return;
}
tokenList.NextToken();
if (tokenList.GetCurrentTokenType() != Enums.TokenType.numbersym)
{
error = Enums.GeneratorError.EQUAL_NOT_FOLLOWED_BY_NUM;
return;
}
newSymbol.value = int.Parse(tokenList.GetCurrentToken().lexeme);
newSymbol.scope = currentScope;
symbolTable.Add(newSymbol);
tokenList.NextToken();
} while (tokenList.GetCurrentTokenType() == Enums.TokenType.commasym);
if (tokenList.GetCurrentTokenType() != Enums.TokenType.semicolonsym)
{
error = Enums.GeneratorError.SEMICOLON_MISSING;
return;
}
tokenList.NextToken();
}
}
public Generator()
{
error = Enums.GeneratorError.NONE;
symbolTable = null;
currentScope = null;
instructions = null;
tokenList = null;
currentLevel = 0;
nextCodeIndex = 0;
currentRegister = 0;
}
private void VariablesDeclaration()
{
if (tokenList.GetCurrentTokenType() == Enums.TokenType.varsym)
{
int numVariables = 1;
do
{
tokenList.NextToken();
Symbol newSymbol = new Symbol();
newSymbol.type = Enums.TokenType.varsym;
newSymbol.level = currentLevel;
if (currentLevel == 1)
{
newSymbol.address = numVariables;
}
else
{
newSymbol.address = numVariables + 4;
}
numVariables++;
if (tokenList.GetCurrentTokenType() != Enums.TokenType.identsym)
{
error = Enums.GeneratorError.RESERVED_NOT_FOLLOWED_BY_IDENT;
return;
}
newSymbol.name = tokenList.GetCurrentToken().lexeme;
newSymbol.scope = currentScope;
symbolTable.Add(newSymbol);
tokenList.NextToken();
} while (tokenList.GetCurrentTokenType() == Enums.TokenType.commasym);
Emit((int)Enums.OpCode.INC, 0, 0, numVariables);
if (tokenList.GetCurrentTokenType() != Enums.TokenType.semicolonsym)
{
error = Enums.GeneratorError.SEMICOLON_MISSING;
return;
}
tokenList.NextToken();
}
}
private void Program()
{
currentRegister++;
Block();
if (error != Enums.GeneratorError.NONE)
{
return;
}
if (tokenList.GetCurrentTokenType() == Enums.TokenType.periodsym)
{
tokenList.NextToken();
Emit((int)Enums.OpCode.SIO_HALT, 0, 0, 3);
return;
}
error = Enums.GeneratorError.PERIOD_EXPECTED;
return;
}
private void Factor()
{
if (tokenList.GetCurrentTokenType() == Enums.TokenType.identsym)
{
Symbol symbol = Symbol.FindSymbol(symbolTable, currentScope, tokenList.GetCurrentToken().lexeme);
if (symbol == null)
{
error = Enums.GeneratorError.IDENT_OUTOFSCOPE;
return;
}
if (symbol.type == Enums.TokenType.constsym)
{
Emit((int)Enums.OpCode.LIT, currentRegister, 0, symbol.value);
}
else if (symbol.type == Enums.TokenType.varsym)
{
Emit((int)Enums.OpCode.LOD, currentRegister, currentLevel - symbol.level, symbol.address);
}
currentRegister++;
tokenList.NextToken();
return;
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.numbersym)
{
Emit((int)Enums.OpCode.LIT, currentRegister, 0, int.Parse(tokenList.GetCurrentToken().lexeme));
currentRegister++;
tokenList.NextToken();
return;
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.lparentsym)
{
tokenList.NextToken();
Expression();
if (error != Enums.GeneratorError.NONE)
{
return;
}
if (tokenList.GetCurrentTokenType() != Enums.TokenType.rparentsym)
{
error = Enums.GeneratorError.RIGHT_PARENTH_MISSING;
return;
}
tokenList.NextToken();
}
else
{
error = Enums.GeneratorError.MISSING_SYMBOL;
return;
}
}
private void Condition()
{
if (tokenList.GetCurrentTokenType() == Enums.TokenType.oddsym)
{
tokenList.NextToken();
Expression();
if (error != Enums.GeneratorError.NONE)
{
return;
}
}
else
{
Expression();
if (error != Enums.GeneratorError.NONE)
{
return;
}
Enums.TokenType currentTokenType = tokenList.GetCurrentTokenType();
tokenList.NextToken();
Expression();
if (error != Enums.GeneratorError.NONE)
{
return;
}
if (tokenList.GetCurrentTokenType() == Enums.TokenType.eqsym)
{
Emit((int)Enums.OpCode.EQL, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.neqsym)
{
Emit((int)Enums.OpCode.NEQ, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.lessym)
{
Emit((int)Enums.OpCode.LSS, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.leqsym)
{
Emit((int)Enums.OpCode.LEQ, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.gtrsym)
{
Emit((int)Enums.OpCode.GTR, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.geqsym)
{
Emit((int)Enums.OpCode.GEQ, currentRegister - 2, currentRegister - 2, currentRegister - 1);
}
else
{
error = Enums.GeneratorError.RELATIONAL_OP_EXPECTED;
return;
}
currentRegister--;
}
}
private void Statement()
{
if (tokenList.GetCurrentTokenType() == Enums.TokenType.identsym)
{
Symbol symbol = Symbol.FindSymbol(symbolTable, currentScope, tokenList.GetCurrentToken().lexeme);
if (symbol == null)
{
error = Enums.GeneratorError.IDENT_OUTOFSCOPE;
return;
}
tokenList.NextToken();
if (symbol.type != Enums.TokenType.varsym)
{
error = Enums.GeneratorError.ASSIGNMENT_CONST_PROC_IMPOSSIBLE;
return;
}
if (tokenList.GetCurrentTokenType() != Enums.TokenType.becomessym)
{
error = Enums.GeneratorError.ASSIGNMENT_OP_EXPECTED;
return;
}
tokenList.NextToken();
Expression();
if (error != Enums.GeneratorError.NONE)
{
return;
}
Emit((int)Enums.OpCode.STO, currentRegister - 1, currentLevel - symbol.level, symbol.address);
currentRegister--;
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.callsym)
{
tokenList.NextToken();
if (tokenList.GetCurrentTokenType() != Enums.TokenType.identsym)
{
error = Enums.GeneratorError.CALL_NOT_FOLLOWED_BYIDENT;
return;
}
Symbol symbol = Symbol.FindSymbol(symbolTable, currentScope, tokenList.GetCurrentToken().lexeme);
if (symbol == null)
{
error = Enums.GeneratorError.IDENT_OUTOFSCOPE;
return;
}
if (symbol.type != Enums.TokenType.procsym)
{
error = Enums.GeneratorError.CALL_CONST_VAR_IMPOSSIBLE;
return;
}
Emit((int)Enums.OpCode.CAL, 0, currentLevel - symbol.level, symbol.address);
tokenList.NextToken();
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.beginsym)
{
do
{
tokenList.NextToken();
Statement();
if (error != Enums.GeneratorError.NONE)
{
return;
}
} while (tokenList.GetCurrentTokenType() == Enums.TokenType.semicolonsym);
if (tokenList.GetCurrentTokenType() != Enums.TokenType.endsym)
{
error = Enums.GeneratorError.SEMICOLON_OR_END_EXPECTED;
return;
}
tokenList.NextToken();
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.ifsym)
{
tokenList.NextToken();
Condition();
if (error != Enums.GeneratorError.NONE)
{
return;
}
if (tokenList.GetCurrentTokenType() == Enums.TokenType.thensym)
{
error = Enums.GeneratorError.THEN_EXPECTED;
return;
}
tokenList.NextToken();
int cTemp = nextCodeIndex;
Emit((int)Enums.OpCode.JPC, currentRegister - 1, 0, 0);
Statement();
if (error != Enums.GeneratorError.NONE)
{
return;
}
int cTempElse = nextCodeIndex;
Emit((int)Enums.OpCode.JMP, 0, 0, 0);
instructions[cTemp].M = nextCodeIndex;
if (tokenList.GetCurrentTokenType() == Enums.TokenType.elsesym)
{
tokenList.NextToken();
instructions[cTemp].M = nextCodeIndex;
cTemp = nextCodeIndex;
Statement();
if (error != Enums.GeneratorError.NONE)
{
return;
}
}
instructions[cTempElse].M = nextCodeIndex;
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.whilesym)
{
tokenList.NextToken();
int cTemp1 = nextCodeIndex;
Condition();
if (error != Enums.GeneratorError.NONE)
{
return;
}
int cTemp2 = nextCodeIndex;
Emit((int)Enums.OpCode.JPC, currentRegister - 1, 0, 0);
if (tokenList.GetCurrentTokenType() != Enums.TokenType.dosym)
{
error = Enums.GeneratorError.DO_EXPECTED;
return;
}
tokenList.NextToken();
Statement();
if (error != Enums.GeneratorError.NONE)
{
return;
}
Emit((int)Enums.OpCode.JMP, 0, 0, cTemp1);
instructions[cTemp2].M = nextCodeIndex;
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.readsym)
{
tokenList.NextToken();
Emit((int)Enums.OpCode.SIO_READ, currentRegister, 0, 1);
if (tokenList.GetCurrentTokenType() == Enums.TokenType.identsym)
{
error = Enums.GeneratorError.RESERVED_NOT_FOLLOWED_BY_IDENT;
return;
}
Symbol symbol = Symbol.FindSymbol(symbolTable, currentScope, tokenList.GetCurrentToken().lexeme);
if (symbol == null)
{
error = Enums.GeneratorError.IDENT_OUTOFSCOPE;
return;
}
if (symbol.type == Enums.TokenType.varsym)
{
error = Enums.GeneratorError.READ_TO_CONST_PROC_IMPOSSIBLE;
return;
}
Emit((int)Enums.OpCode.STO, currentRegister, currentLevel - symbol.level, symbol.address);
tokenList.NextToken();
}
else if (tokenList.GetCurrentTokenType() == Enums.TokenType.writesym)
{
tokenList.NextToken();
if (tokenList.GetCurrentTokenType() != Enums.TokenType.identsym)
{
error = Enums.GeneratorError.RESERVED_NOT_FOLLOWED_BY_IDENT;
return;
}
Symbol symbol = Symbol.FindSymbol(symbolTable, currentScope, tokenList.GetCurrentToken().lexeme);
if (symbol == null)
{
error = Enums.GeneratorError.IDENT_OUTOFSCOPE;
return;
}
if (symbol.type == Enums.TokenType.procsym)
{
error = Enums.GeneratorError.WRITE_TO_PROC_IMPOSSIBLE;
return;
}
if (symbol.type == Enums.TokenType.constsym)
{
Emit((int)Enums.OpCode.LIT, currentRegister - 1, 0, symbol.value);
}
else if (symbol.type == Enums.TokenType.varsym)
{
Emit((int)Enums.OpCode.LOD, currentRegister - 1, 0, 2);
}
Emit((int)Enums.OpCode.SIO_WRITE, currentRegister - 1, 0, 2);
tokenList.NextToken();
}
}
private void ProceduresDeclaration(int jumpIndex)
{
while (tokenList.GetCurrentTokenType() == Enums.TokenType.procsym)
{
tokenList.NextToken();
Symbol newSymbol = new Symbol();
newSymbol.type = Enums.TokenType.procsym;
newSymbol.level = currentLevel;
newSymbol.address = jumpIndex + 1;
if (tokenList.GetCurrentTokenType() != Enums.TokenType.identsym)
{
error = Enums.GeneratorError.RESERVED_NOT_FOLLOWED_BY_IDENT;
return;
}
newSymbol.name = tokenList.GetCurrentToken().lexeme;
newSymbol.scope = currentScope;
symbolTable.Add(newSymbol);
Symbol oldScope = currentScope;
Symbol newScope = newSymbol;
tokenList.NextToken();
if (tokenList.GetCurrentTokenType() != Enums.TokenType.semicolonsym)
{
error = Enums.GeneratorError.SEMICOLON_MISSING;
return;
}
tokenList.NextToken();
currentScope = newScope;
Emit((int)Enums.OpCode.INC, 0, 0, 0);
Block();
if (error != Enums.GeneratorError.NONE)
{
return;
}
currentScope = oldScope;
jumpIndex = nextCodeIndex;
Emit((int)Enums.OpCode.RTN, 0, 0, 0);
if (tokenList.GetCurrentTokenType() != Enums.TokenType.semicolonsym)
{
error = Enums.GeneratorError.SEMICOLON_OR_END_EXPECTED;
return;
}
tokenList.NextToken();
}
;
}