public IParseItem Visit(ForGenItem target)
{
if (target == null)
{
throw new ArgumentNullException(nameof(target));
}
using (_tree.Block(true)) {
_tree.DefineLocal(target.Names);
_tree.DefineLabel(target.Break);
target.Block.Accept(this);
foreach (var item in target.Expressions)
{
item.Accept(this);
}
}
return(target);
}
/// <summary>
/// Called when the item is a for generic item.
/// </summary>
/// <param name="target">The object that was passed to IParseItem.Accept.</param>
/// <returns>The passed target or a modification of it.</returns>
/// <exception cref="System.ArgumentNullException">If target is null.</exception>
public IParseItem Visit(ForGenItem target)
{
if (target == null)
{
throw new ArgumentNullException(nameof(target));
}
ILGenerator gen = compiler.CurrentGenerator;
target.Break.UserData = target.Break.UserData ?? gen.DefineLabel();
Label start = gen.DefineLabel(), end = (Label)target.Break.UserData;
LocalBuilder ret = compiler.CreateTemporary(typeof(ILuaMultiValue));
LocalBuilder enumerable = compiler.CreateTemporary(typeof(IEnumerable <ILuaMultiValue>));
LocalBuilder enumerator = compiler.CreateTemporary(typeof(IEnumerator <ILuaMultiValue>));
using (compiler.LocalBlock())
{
// temp = new ILuaValue[...];
var temp = compiler.CreateArray(typeof(ILuaValue), target.Expressions.Count);
for (int i = 0; i < target.Expressions.Count; i++)
{
// temp[{i}] = {item};
gen.Emit(OpCodes.Ldloc, temp);
gen.Emit(OpCodes.Ldc_I4, i);
target.Expressions[i].Accept(this);
gen.Emit(OpCodes.Stelem, typeof(ILuaValue));
}
// enumerable = E.Runtime.GenericLoop(E, new LuaMultiValue(temp));
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Callvirt, typeof(ILuaEnvironment).GetProperty(nameof(ILuaEnvironment.Runtime)).GetGetMethod());
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Callvirt, typeof(ILuaEnvironment).GetProperty(nameof(ILuaEnvironment.Runtime)).GetGetMethod());
gen.Emit(OpCodes.Ldloc, temp);
gen.Emit(OpCodes.Callvirt, typeof(ILuaRuntime).GetMethod(nameof(ILuaRuntime.CreateMultiValue)));
gen.Emit(OpCodes.Callvirt, typeof(ILuaRuntime).GetMethod(nameof(ILuaRuntime.GenericLoop)));
gen.Emit(OpCodes.Stloc, enumerable);
compiler.RemoveTemporary(temp);
// enumerator = enumerable.GetEnumerator();
gen.Emit(OpCodes.Ldloc, enumerable);
gen.Emit(OpCodes.Callvirt, typeof(IEnumerable <ILuaMultiValue>).GetMethod(nameof(IEnumerable.GetEnumerator)));
gen.Emit(OpCodes.Stloc, enumerator);
// try {
Label endTry = gen.BeginExceptionBlock();
gen.MarkLabel(start);
// if (!enumerator.MoveNext) goto end;
gen.Emit(OpCodes.Ldloc, enumerator);
gen.Emit(OpCodes.Callvirt, typeof(IEnumerator).GetMethod(nameof(IEnumerator.MoveNext)));
gen.Emit(OpCodes.Brfalse, end);
// ILuaMultiValue ret = enumerator.Current;
gen.Emit(OpCodes.Ldloc, enumerator);
gen.Emit(OpCodes.Callvirt, typeof(IEnumerator <ILuaMultiValue>)
.GetProperty(nameof(IEnumerator <ILuaMultiValue> .Current)).GetGetMethod());
gen.Emit(OpCodes.Stloc, ret);
compiler.RemoveTemporary(enumerator);
for (int i = 0; i < target.Names.Count; i++)
{
// {_names[i]} = ret[{i}];
var field = compiler.DefineLocal(target.Names[i]);
field.StartSet();
gen.Emit(OpCodes.Ldloc, ret);
gen.Emit(OpCodes.Ldc_I4, i);
gen.Emit(OpCodes.Callvirt, typeof(ILuaMultiValue).GetMethod("get_Item"));
field.EndSet();
}
compiler.RemoveTemporary(ret);
// {Block}
target.Block.Accept(this);
// goto start;
gen.Emit(OpCodes.Br, start);
// end:
gen.MarkLabel(end);
// } finally {
gen.Emit(OpCodes.Leave, endTry);
gen.BeginFinallyBlock();
// if (enumerable != null) enumerable.Dispose();
Label endFinally = gen.DefineLabel();
gen.Emit(OpCodes.Ldloc, enumerable);
gen.Emit(OpCodes.Brfalse, endFinally);
gen.Emit(OpCodes.Ldloc, enumerable);
gen.Emit(OpCodes.Callvirt, typeof(IDisposable).GetMethod(nameof(IDisposable.Dispose)));
gen.MarkLabel(endFinally);
compiler.RemoveTemporary(enumerable);
// }
gen.EndExceptionBlock();
}
return(target);
}
