private Type binary_optional_left_expr(ParserRuleContext context, ParserRuleContext left, IToken op, ParserRuleContext right)
{
if (left == null)
{
Type t = right.Accept(this);
type_dict[context] = t;
return(t);
}
Type left_type = left.Accept(this);
Type right_type = right.Accept(this);
Type resulting_type = get_binary_operator_result(left_type, right_type, op);
type_dict[context] = resulting_type;
Debug.Assert(resulting_type != null && resulting_type != typeof(void));
return(resulting_type);
}
private ObjectType VisitLogicalExpression(ParserRuleContext context, string op, ParserRuleContext left,
ParserRuleContext right)
{
var leftType = left.Accept(this);
var rightType = right.Accept(this);
if (leftType == ObjectType.Boolean &&
rightType == ObjectType.Boolean)
{
return(ObjectType.Boolean);
}
_scriptEnvironmentBuilder.Errors.Add(new InvalidOperandsException(context, op, leftType, rightType));
return(ObjectType.Unknown);
}
//public override ObjectType VisitArithmeticExpression(QuestScriptParser.ArithmeticExpressionContext context)
private ObjectType VisitArithmeticExpression(ParserRuleContext context, ParserRuleContext op,
ParserRuleContext left, ParserRuleContext right)
{
var leftType = left.Accept(this);
var rightType = right.Accept(this);
//if at least one is unknown, then we already have an error and can stop evaluating types
if (leftType == ObjectType.Unknown || rightType == ObjectType.Unknown)
{
return(ObjectType.Unknown);
}
if (leftType == rightType)
{
return(leftType);
}
//we don't want to lose precision, thus any arithmetic expression with double operand becomes double too
if (TypeUtil.IsNumeric(rightType) &&
TypeUtil.IsNumeric(leftType) &&
(leftType == ObjectType.Double || rightType == ObjectType.Double))
{
return(ObjectType.Double);
}
if (TypeUtil.CanConvert(rightType, leftType))
{
return(leftType);
}
if (TypeUtil.CanConvert(leftType, rightType))
{
return(rightType);
}
_scriptEnvironmentBuilder.Errors.Add(new InvalidOperandsException(context, op.GetText(), leftType,
rightType));
return(ObjectType.Unknown);
}
private Lazy <object> VisitArithmeticExpression(ParserRuleContext context, ParserRuleContext op,
ParserRuleContext left, ParserRuleContext right)
{
var expressionType = _scriptEnvironmentBuilder.TypeInferenceVisitor.Visit(context);
if (!TypeUtil.IsNumeric(expressionType) && expressionType != ObjectType.String)
{
_scriptEnvironmentBuilder.Errors.Add(
new InvalidOperandsException(
context,
op.GetText(),
_scriptEnvironmentBuilder.TypeInferenceVisitor.Visit(left),
_scriptEnvironmentBuilder.TypeInferenceVisitor.Visit(right)));
return(new Lazy <object>(() => null));
}
return(new Lazy <object>(() =>
{
var leftValue = left.Accept(this).GetValueOrLazyValue();
var rightValue = right.Accept(this).GetValueOrLazyValue();
if (op.GetText() == "+")
{
//maybe we have string concatenation?
if (leftValue is string leftStr)
{
return leftStr + rightValue;
}
if (rightValue is string rightStr)
{
return leftValue + rightStr;
}
}
if (!(leftValue is int) && !(leftValue is double) ||
!(rightValue is int) && !(rightValue is double))
{
return null;
}
bool TryConvertToNumber(object value, out double result)
{
result = 0;
try
{
result = Convert.ToDouble(value);
}
catch (InvalidCastException e)
{
Errors.Add(new FailedToInferTypeException(context, left, e));
return false;
}
return true;
}
if (!TryConvertToNumber(leftValue, out var leftValueAsNumber))
{
return null;
}
if (!TryConvertToNumber(rightValue, out var rightValueAsNumber))
{
return null;
}
switch (op.GetText())
{
case "+":
return Cast(leftValueAsNumber + rightValueAsNumber, expressionType);
case "-":
return Cast(leftValueAsNumber - rightValueAsNumber, expressionType);
case "/":
if (Math.Abs(rightValueAsNumber) < 0.00000000001) //epsilon :)
{
var error = new DivisionByZeroException(context);
Errors.Add(error);
}
var val = leftValueAsNumber / rightValueAsNumber;
return Cast(val, expressionType);
case "%":
return Cast(leftValueAsNumber % rightValueAsNumber, expressionType);
case "*":
return Cast(leftValueAsNumber * rightValueAsNumber, expressionType);
}
//if not numeric and not string concatenation, nothing to do...
return null;
}));
}