private RuntimeResult VisitWhileNode(WhileNode node, Context context)
{
RuntimeResult condResult = Visit(node.Condition, context);
if (condResult.HasError)
{
return(condResult);
}
Values.Value output = new Values.NullValue().SetPositionAndContext(node.Position, context);
while (condResult.Value.GetAsBoolean())
{
RuntimeResult bodyResult = Visit(node.Body, context);
if (bodyResult.HasError)
{
return(bodyResult);
}
if (context.Return)
{
return(bodyResult);
}
output = bodyResult.Value;
if (context.Break)
{
context.Break = false;
break;
}
condResult = Visit(node.Condition, context);
if (condResult.HasError)
{
return(condResult);
}
}
return(new RuntimeResult(output));
}
private RuntimeResult VisitReturnNode(ReturnNode node, Context context)
{
if (node.Node == null)
{
Values.Value val = new Values.NullValue().SetPositionAndContext(node.Position, context);
context.Return = true;
return(new RuntimeResult(val));
}
else
{
RuntimeResult result = Visit(node.Node, context);
if (result.HasError)
{
return(result);
}
context.Return = true;
return(new RuntimeResult(result.Value));
}
}
private RuntimeResult VisitDoNode(DoNode node, Context context)
{
Values.Value output = new Values.NullValue().SetPositionAndContext(node.Position, context);
while (true)
{
RuntimeResult bodyResult = Visit(node.Body, context);
if (bodyResult.HasError)
{
return(bodyResult);
}
output = bodyResult.Value;
RuntimeResult condResult = Visit(node.Condition, context);
if (condResult.HasError)
{
return(condResult);
}
if (!condResult.Value.GetAsBoolean())
{
break;
}
}
return(new RuntimeResult(output));
}
private RuntimeResult VisitBlockNode(BlockNode node, Context context)
{
Values.Value output = new Values.NullValue().SetPositionAndContext(node.Position, context);
for (int i = 0; i < node.Statements.Count; i++)
{
RuntimeResult runtimeResult = Visit(node.Statements[i], context);
if (runtimeResult.HasError)
{
return(runtimeResult);
}
if (context.Return)
{
return(runtimeResult);
}
if (context.Continue)
{
context.Continue = false;
return(runtimeResult);
}
output = runtimeResult.Value;
}
return(new RuntimeResult(output));
}
private RuntimeResult VisitForNode(ForNode node, Context context)
{
RuntimeResult startResult = Visit(node.Start, context);
if (startResult.HasError)
{
return(startResult);
}
if (startResult.Value.Type != Values.ValueType.INTEGER)
{
return(new RuntimeResult(new RuntimeError(node.Token.Position, "Start value must be an integer", context)));
}
int start = (int)startResult.Value.Data;
RuntimeResult endResult = Visit(node.End, context);
if (endResult.HasError)
{
return(endResult);
}
if (endResult.Value.Type != Values.ValueType.INTEGER)
{
return(new RuntimeResult(new RuntimeError(node.Token.Position, "Stop value must be an integer", context)));
}
int end = (int)endResult.Value.Data;
int step = 1;
if (node.Step != null)
{
RuntimeResult stepResult = Visit(node.Step, context);
if (stepResult.HasError)
{
return(stepResult);
}
if (endResult.Value.Type != Values.ValueType.INTEGER)
{
return(new RuntimeResult(new RuntimeError(node.Token.Position, "Step value must be an integer", context)));
}
step = (int)stepResult.Value.Data;
}
string id = node.Token.Value.ToString();
context.AddSymbol(id, startResult.Value);
Values.Value output = new Values.NullValue().SetPositionAndContext(node.Token.Position, context);
if (step > 0)
{
while (start < end)
{
RuntimeResult bodyResult = Visit(node.Body, context);
if (bodyResult.HasError)
{
return(bodyResult);
}
if (context.Return)
{
return(bodyResult);
}
output = bodyResult.Value;
if (context.Break)
{
context.Break = false;
break;
}
start += step;
startResult.Value.Data = start;
}
}
else
{
while (start > end)
{
RuntimeResult bodyResult = Visit(node.Body, context);
if (bodyResult.HasError)
{
return(bodyResult);
}
if (context.Return)
{
return(bodyResult);
}
output = bodyResult.Value;
if (context.Break)
{
context.Break = false;
break;
}
start += step;
startResult.Value.Data = start;
}
}
return(new RuntimeResult(output));
}