internal override bool TypeCheck(out Type type)
{
type = Type.NULL;
if (expression is not null)
{
if (CurrentFunction.returnType == Type.VOID)
{
Error("Return statement cannot have value in void function");
return(false);
}
if (expression.TypeCheck(out Type returnType))
{
if (!AssignmentTypeHelper(CurrentFunction.returnType, returnType))
{
Error($"Return type doens't match. Expect: {TypeString(CurrentFunction.returnType)}," +
$" Got: {TypeString(returnType)}");
return(false);
}
}
else
{
return(false);
}
}
this.function = CurrentFunction;
return(true);
}
public Statement Parse()
{
GetNextToken();
//Array containing all accepted tokens by the print statement
Token[] acceptedPrintTokens = new[]
{
Token.String,
Token.BoolTrue,
Token.BoolFalse,
Token.Number,
Token.VariableName,
Token.Not,
Token.Minus
};
//PRINT statement check/parse
if (LastToken == Token.Print && acceptedPrintTokens.Contains(CurrentToken))
{
return(new PrintStatement(EvaluateExpression()));
}
//FUNCTION definition statement check/parse
if (LastToken == Token.FunctionDef && CurrentToken == Token.FunctionName)
{
List <Statement> statements = new List <Statement>();
List <Argument> arguments = new List <Argument>();
//Gets the arguments for the function
GetNextToken();
while (CurrentToken != Token.OpenBrace)
{
GetNextToken();
if (LastToken == Token.Argument && (CurrentToken == Token.BoolVariable || CurrentToken == Token.NumberVariable || CurrentToken == Token.StringVariable))
{
GetNextToken();
if (CurrentToken == Token.VariableName)
{
Argument argument = new Argument();
argument.ArgumentName = VariableName;
GeneralSymbol symbol = new GeneralSymbol();
Dictionary <Token, Enums.Type> tokenConversion = new Dictionary <Token, Enums.Type>
{
{ Token.StringVariable, Enums.Type.String },
{ Token.NumberVariable, Enums.Type.Number },
{ Token.BoolVariable, Enums.Type.Bool }
};
symbol.Type = tokenConversion[LastToken];
argument.Value = symbol;
arguments.Add(argument);
GetNextToken();
}
else
{
throw new Exception("Expecting argument name!");
}
}
else
{
throw new Exception("Expecting type after argument");
}
}
//Gets the statements for the function
if (CurrentToken == Token.OpenBrace)
{
GetNextToken();
while (CurrentToken != Token.CloseBrace)
{
statements.Add(Parse());
}
FunctionDefinitionStatement function = new FunctionDefinitionStatement(statements, arguments, FunctionName);
_statements.Add(function);
}
}
//Checks for function call
if (CurrentToken == Token.FunctionCall)
{
GetNextToken();
if (CurrentToken == Token.FunctionName)
{
GetNextToken();
List <Argument> arguments = new List <Argument>();
while (CurrentToken != Token.Semi && CurrentToken != Token.EndFile)
{
if (CurrentToken == Token.String || CurrentToken == Token.Number ||
CurrentToken == Token.BoolFalse || CurrentToken == Token.BoolTrue ||
CurrentToken == Token.Minus || CurrentToken == Token.VariableName)
{
Argument argument = new Argument();
argument.Value = EvaluateExpression().Evaluate();
arguments.Add(argument);
}
GetNextToken();
}
return(new FunctionCallStatement(FunctionName, arguments));
}
}
//Checks for variable decleration
if (CurrentToken == Token.NumberVariable || CurrentToken == Token.StringVariable || CurrentToken == Token.BoolVariable)
{
GetNextToken();
if (CurrentToken == Token.VariableName)
{
GetNextToken();
if (CurrentToken == Token.VariableAssignment)
{
GetNextToken();
if (CurrentToken == Token.String || CurrentToken == Token.Number || CurrentToken == Token.BoolFalse || CurrentToken == Token.BoolTrue || CurrentToken == Token.Minus || CurrentToken == Token.VariableName)
{
//Finds the type of variable which is being declared
Enums.Type type = Enums.Type.Null;
Dictionary <Token, Enums.Type> tokenConversion = new Dictionary <Token, Enums.Type>
{
{ Token.StringVariable, Enums.Type.String },
{ Token.NumberVariable, Enums.Type.Number },
{ Token.BoolVariable, Enums.Type.Bool }
};
type = tokenConversion[ThirdLastToken];
VariableDeclerationStatement variableDecleration =
new VariableDeclerationStatement(type, VariableName, EvaluateExpression());
variableDecleration.Execute();
return(variableDecleration);
}
else
{
throw new Exception("Unknown type");
}
}
}
else
{
throw new Exception("Invalid variable name");
}
}
//Checks for variable assignment
if (CurrentToken == Token.VariableName && LastToken == Token.Semi)
{
GetNextToken();
if (CurrentToken == Token.VariableAssignment)
{
GetNextToken();
if (CurrentToken == Token.String || CurrentToken == Token.Number || CurrentToken == Token.BoolTrue || CurrentToken == Token.BoolFalse || CurrentToken == Token.Not || CurrentToken == Token.VariableName)
{
return(new VariableAssignmentStatement(VariableName, EvaluateExpression()));
}
else
{
throw new Exception("Unknown type");
}
}
else
{
throw new Exception("Missing = after variable name");
}
}
if (CurrentToken == Token.VariableName && (LastToken != Token.BoolVariable && LastToken != Token.StringVariable && LastToken != Token.NumberVariable))
{
throw new Exception("Variable does not exists in scope");
}
//Console.WriteLine("Time taken to compile: " + (DateTime.Now - startTime) + "\n");
return(null);
}
