public override bool VisitAssignmentStatement(QuestScriptParser.AssignmentStatementContext context)
{
var success = base.VisitAssignmentStatement(context);
var identifier = context.LVal.GetText();
var variable = _current.GetVariable(identifier);
var variableDefined = variable != null;
var isMemberAssignment = identifier.Contains(".");
if (!isMemberAssignment && !variableDefined)
{
DeclareLocalVariable(identifier, context.LVal, context.RVal);
}
else if (variableDefined && !isMemberAssignment) //do a type check, since we are not declaring but assigning
{
//do type checking, since this is not a declaration but an assignment
var rValueType = TypeInferenceVisitor.Visit(context.RVal);
var lValueType = TypeInferenceVisitor.Visit(context.LVal);
if (lValueType != rValueType && !TypeUtil.CanConvert(rValueType, lValueType))
{
Errors.Add(new UnexpectedTypeException(context, lValueType, rValueType, context.RVal,
"Also, tried to find suitable implicit casting, but didn't find anything."));
}
variable.Value = ValueResolverVisitor.Visit(context.RVal);
}
return(success);
}
public override bool VisitForEachStatement(QuestScriptParser.ForEachStatementContext context)
{
_current = _current.CreateChild(context); //push
var enumerationVariableType = TypeInferenceVisitor.Visit(context.enumerationVariable);
if (enumerationVariableType != ObjectType.List)
{
Errors.Add(new UnexpectedTypeException(context, ObjectType.List, enumerationVariableType,
context.enumerationVariable, "'foreach' can only enumerate on collection types."));
}
if (!_current.IsVariableDefined(context.iterationVariable.Text))
{
DeclareLocalVariable(context.iterationVariable.Text, context, context.enumerationVariable,
isEnumerationVariable: true);
}
else
{
Errors.Add(
new ConflictingVariableName(context, context.iterationVariable.Text,
"Iteration variable names in 'foreach' statements must not conflict with already defined variables."));
}
var success = base.VisitForEachStatement(context);
_current = _current.Parent; //pop
return(success);
}
private void DeclareLocalVariable(string name, ParserRuleContext variableContext,
ParserRuleContext valueContext, bool isEnumerationVariable = false, bool isIterationVariable = false)
{
var type = TypeInferenceVisitor.Visit(valueContext);
_current.LocalVariables.Add(new Variable
{
Name = name,
Type = type,
IsEnumerationVariable = isEnumerationVariable,
IsIterationVariable = isIterationVariable,
Context = variableContext,
Value = ValueResolverVisitor.Visit(valueContext)
});
}
//if condition type check - make sure it resolves to boolean type
public override bool VisitIfStatement(QuestScriptParser.IfStatementContext context)
{
var ifConditionExpressionType = TypeInferenceVisitor.Visit(context.condition);
if (ifConditionExpressionType != ObjectType.Unknown &&
ifConditionExpressionType != ObjectType.Boolean)
{
Errors.Add(new InvalidConditionException(context, "if", context.condition));
}
foreach (var elseifCondition in context._elseifConditions)
{
var elseIfConditionExpressionType = TypeInferenceVisitor.Visit(elseifCondition);
if (elseIfConditionExpressionType != ObjectType.Unknown &&
elseIfConditionExpressionType != ObjectType.Boolean)
{
Errors.Add(new InvalidConditionException(context, "elseif", elseifCondition));
}
}
return(base.VisitIfStatement(context));
}
public ScriptEnvironmentBuilder()
{
TypeInferenceVisitor = new TypeInferenceVisitor(this);
ValueResolverVisitor = new ValueResolverVisitor(this);
}