/// <summary>
/// 暗黙の型変換が存在する場合，それを利用する。
/// </summary>
private DynamicMetaObject TryImplicitCast(DynamicMetaObject left, DynamicMetaObject right)
{
Expression cmpExpr = null;
if (BinderHelper.GetImplicitCast(left.LimitType, right.LimitType) != null)
{
try {
cmpExpr = Expression.MakeBinary(this.Operation,
BinderHelper.Wrap(left.Expression, left.LimitType, right.LimitType),
BinderHelper.Wrap(right.Expression, right.LimitType));
}
catch (InvalidCastException) { }
}
if (BinderHelper.GetImplicitCast(right.LimitType, left.LimitType) != null)
{
try {
cmpExpr = Expression.MakeBinary(this.Operation,
BinderHelper.Wrap(left.Expression, left.LimitType),
BinderHelper.Wrap(right.Expression, right.LimitType, left.LimitType));
}
catch (InvalidCastException) { }
}
if (cmpExpr == null)
{
return(null);
}
var expr = BinderHelper.Wrap(cmpExpr, this.ReturnType);
var rest = BinderHelper.GetTypeRestriction(left, right);
return(new DynamicMetaObject(expr, rest));
}
/// <summary>
/// 暗黙のキャストを探す。
/// </summary>
private DynamicMetaObject DefferentType(DynamicMetaObject left, DynamicMetaObject right)
{
var val = TryCalcNumeric(left, right);
if (val != null)
{
return(val);
}
// 左辺のキャスト
var mInfo = BinderHelper.GetImplicitCast(left.LimitType, right.LimitType);
if (mInfo != null)
{
Expression expr = Expression.MakeBinary(this.Operation,
BinderHelper.Wrap(left.Expression, left.LimitType, right.LimitType),
Expression.Convert(right.Expression, right.LimitType));
return(new DynamicMetaObject(
BinderHelper.Wrap(expr, this.ReturnType),
BinderHelper.GetTypeRestriction(left, right)));
}
// 右辺のキャスト
mInfo = BinderHelper.GetImplicitCast(right.LimitType, left.LimitType);
if (mInfo != null)
{
Expression expr = Expression.MakeBinary(this.Operation,
Expression.Convert(left.Expression, left.LimitType),
BinderHelper.Wrap(right.Expression, right.LimitType, left.LimitType));
return(new DynamicMetaObject(
BinderHelper.Wrap(expr, this.ReturnType),
BinderHelper.GetTypeRestriction(left, right)));
}
return(BinderHelper.NoResult(_name, this.ReturnType, left, right));
}