/// <summary>
/// Called when the item is a return item.
/// </summary>
/// <param name="target">The object that was passed to IParseItem.Visit.</param>
/// <returns>The passed target or a modification of it.</returns>
/// <exception cref="System.ArgumentNullException">If target is null.</exception>
public IParseItem Visit(ReturnItem target)
{
if (target == null)
throw new ArgumentNullException("target");
ILGenerator gen = compiler.CurrentGenerator;
if (target.Expressions.Count == 1 && target.Expressions[0] is FuncCallItem)
{
((FuncCallItem)target.Expressions[0]).IsTailCall = true;
target.Expressions[0].Accept(this);
return target;
}
// ILuaValue[] loc = new ILuaValue[{Expressions.Count}];
LocalBuilder loc = compiler.CreateArray(typeof(ILuaValue), target.Expressions.Count);
for (int i = 0; i < target.Expressions.Count; i++)
{
// loc[{i}] = {Expressions[i]};
gen.Emit(OpCodes.Ldloc, loc);
gen.Emit(OpCodes.Ldc_I4, i);
target.Expressions[i].Accept(this);
gen.Emit(OpCodes.Stelem, typeof(ILuaValue));
}
//! push E.Runtime.CreateMultiValue(loc)
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Callvirt, typeof(ILuaEnvironment).GetMethod("get_Runtime"));
gen.Emit(OpCodes.Ldloc, loc);
gen.Emit(OpCodes.Callvirt, typeof(ILuaRuntime).GetMethod("CreateMultiValue"));
compiler.RemoveTemporary(loc);
return target;
}
/// <summary>
/// Called when the item is a return item.
/// </summary>
/// <param name="target">The object that was passed to IParseItem.Visit.</param>
/// <returns>The passed target or a modification of it.</returns>
/// <exception cref="System.ArgumentNullException">If target is null.</exception>
public IParseItem Visit(ReturnItem target)
{
if (target == null)
throw new ArgumentNullException("target");
foreach (var item in target.Expressions)
item.Accept(this);
return target;
}
/// <summary>
/// Reads a return statement from the input.
/// </summary>
/// <param name="input">Where to read input from.</param>
/// <param name="prev">The token to append what is read into.</param>
/// <returns>The object that was read.</returns>
protected virtual ReturnItem ReadReturn(ITokenizer input, ref Token prev)
{
var debug = input.Read(); // read 'return'
ReturnItem r = new ReturnItem();
if (debug.Value != "return")
throw new InvalidOperationException(string.Format(Resources.MustBeOn, "return", "ReadReturn"));
var name = input.Peek();
if (name.Value != "end" && name.Value != "until" && name.Value != "elseif" &&
name.Value != "else")
{
r.AddExpression(ReadExp(input, ref debug));
while (input.Peek().Value == ",")
{
Read(input, ref debug); // read ','
r.AddExpression(ReadExp(input, ref debug));
}
if (input.Peek().Value == ";")
{
Read(input, ref debug); // read ';'
}
// look at the next token for validation but keep it in the
// reader for the parrent.
name = input.Peek();
if (name.Value != "end" && name.Value != "until" && name.Value != "elseif" &&
name.Value != "else" && !IsNullOrWhiteSpace(name.Value))
throw new SyntaxException(
Resources.ReturnAtEnd,
input.Name, debug);
}
prev.Append(debug);
r.Debug = debug;
return r;
}
