/// <summary>
/// Called when the item is a binary expression 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(BinOpItem target)
{
if (target == null)
{
throw new ArgumentNullException(nameof(target));
}
ILGenerator gen = compiler.CurrentGenerator;
if (target.OperationType == BinaryOperationType.And ||
target.OperationType == BinaryOperationType.Or)
{
// object temp = {Lhs};
var end = gen.DefineLabel();
var temp = compiler.CreateTemporary(typeof(ILuaValue));
target.Lhs.Accept(this);
gen.Emit(OpCodes.Stloc, temp);
// Push Lhs onto the stack, if going to end, this will be the result.
gen.Emit(OpCodes.Ldloc, temp);
// if (temp.IsTrue) goto end;
gen.Emit(OpCodes.Ldloc, temp);
gen.Emit(OpCodes.Callvirt, typeof(ILuaValue).GetProperty(nameof(ILuaValue.IsTrue)).GetGetMethod());
if (target.OperationType == BinaryOperationType.And)
{
// We want to break if the value is truthy and it's an OR,
// or it's falsy and it's an AND.
// Boolean negation.
gen.Emit(OpCodes.Ldc_I4_1);
gen.Emit(OpCodes.Xor);
}
gen.Emit(OpCodes.Brtrue, end);
// Replace Lhs on stack with Rhs.
gen.Emit(OpCodes.Pop);
target.Rhs.Accept(this);
// :end
gen.MarkLabel(end);
}
else
{
//! push {Lhs}.Arithmetic({OperationType}, {Rhs})
target.Lhs.Accept(this);
gen.Emit(OpCodes.Ldc_I4, (int)target.OperationType);
target.Rhs.Accept(this);
gen.Emit(OpCodes.Callvirt, typeof(ILuaValue).GetMethod(nameof(ILuaValue.Arithmetic)));
}
return(target);
}
