/// <summary>
/// Called when the item is an assignment 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(AssignmentItem target)
{
if (target == null)
throw new ArgumentNullException("target");
ILGenerator gen = compiler.CurrentGenerator;
// ILuaValue[] loc = new ILuaValue[{target.Expressions.Count}];
LocalBuilder loc = compiler.CreateArray(typeof(ILuaValue), target.Expressions.Count);
// ILuaValue[] names = new ILuaValue[{target.Names.Count}];
LocalBuilder names = compiler.CreateArray(typeof(ILuaValue), target.Names.Count);
// have to evaluate the name indexer expressions before
// setting the values otherwise the following will fail:
// i, t[i] = i+1, 20
for (int i = 0; i < target.Names.Count; i++)
{
if (target.Names[i] is IndexerItem)
{
IndexerItem item = (IndexerItem)target.Names[i];
gen.Emit(OpCodes.Ldloc, names);
gen.Emit(OpCodes.Ldc_I4, i);
item.Expression.Accept(this);
gen.Emit(OpCodes.Stelem, typeof(ILuaValue));
}
}
for (int i = 0; i < target.Expressions.Count; i++)
{
// loc[{i}] = {exps[i]};
gen.Emit(OpCodes.Ldloc, loc);
gen.Emit(OpCodes.Ldc_I4, i);
target.Expressions[i].Accept(this);
gen.Emit(OpCodes.Stelem, typeof(ILuaValue));
}
// ILuaMultiValue exp = E.Runtime.CreateMultiValue(loc);
LocalBuilder exp = compiler.CreateTemporary(typeof(ILuaMultiValue));
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"));
gen.Emit(OpCodes.Stloc, exp);
compiler.RemoveTemporary(loc);
for (int i = 0; i < target.Names.Count; i++)
{
AssignValue(target.Names[i], target.Local,
!(target.Names[i] is IndexerItem) ? (Action)null : () =>
{
// only called if the target object is an indexer item.
// $index = names[{i}];
gen.Emit(OpCodes.Ldloc, names);
gen.Emit(OpCodes.Ldc_I4, i);
gen.Emit(OpCodes.Ldelem, typeof(ILuaValue));
},
() =>
{
// $value = exp[{i}];
gen.Emit(OpCodes.Ldloc, exp);
gen.Emit(OpCodes.Ldc_I4, i);
gen.Emit(OpCodes.Callvirt, typeof(ILuaMultiValue).GetMethod("get_Item"));
});
}
compiler.RemoveTemporary(exp);
compiler.RemoveTemporary(names);
return target;
}
/// <summary>
/// Called when the item is an assignment 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(AssignmentItem target)
{
if (target == null)
throw new ArgumentNullException("target");
if (target.Local)
{
tree.DefineLocal(target.Names.Select(i => i as NameItem));
}
else
{
foreach (var item in target.Names)
item.Accept(this);
}
foreach (var item in target.Expressions)
item.Accept(this);
return target;
}
/// <summary>
/// Reads an assignment statement from the input. The input is currently
/// after the first name, on the comma or equal sign. The debug token
/// contains the name and should contain the entire statement.
/// </summary>
/// <param name="input">Where to read input from.</param>
/// <param name="debug">Currently contains the first name, and after
/// should contain the entire statement.</param>
/// <param name="local">True if this is a local definition, otherwise false.</param>
/// <param name="variable">The first variable that was read.</param>
/// <returns>The statement that was read.</returns>
protected virtual AssignmentItem ReadAssignment(ITokenizer input, ref Token debug, bool local, IParseVariable variable)
{
// read each of the variable names
AssignmentItem assign = new AssignmentItem(local);
assign.AddName(variable);
while (input.Peek().Value == ",")
{
Read(input, ref debug); // read ','
// read the left-hand-expression
var exp = ReadExp(input, ref debug);
if ((local && !(exp is NameItem)) || (!local && !(exp is IParseVariable)))
throw new SyntaxException(Resources.NameOrExpForVar, input.Name, debug);
assign.AddName((IParseVariable)exp);
}
// read the initial values
if (input.Peek().Value == "=")
{
Read(input, ref debug); // read '='
assign.AddItem(ReadExp(input, ref debug));
while (input.Peek().Value == ",")
{
Read(input, ref debug); // read ','
assign.AddItem(ReadExp(input, ref debug));
}
}
else if (!local)
throw new SyntaxException(
string.Format(Resources.InvalidDefinition, "assignment"),
input.Name, debug);
assign.Debug = debug;
return assign;
}