Help needed for "recursive template expansion error"

[Simen Kjærås]

On Tuesday, 22 October 2019 at 08:16:47 UTC, Anthony Abeo wrote:
> On Monday, 21 October 2019 at 18:45:44 UTC, Nicholas Wilson 
> wrote:
>> On Monday, 21 October 2019 at 18:14:11 UTC, Anthony Abeo wrote:
>>> [...]
>>
>> Please post such questions to the learn forum in the future.
>>
>> One way to fix this is to use the `This` type to perform type 
>> substitution in the Algebraic which refers to the final type 
>> of the Algebraic, used like `alias F = Algebraic!(int, string, 
>> This[])`.  Where F is either an int, a string or an array of 
>> Fs.
>>
>> You could probably remove `attributes` from code and use
>>
>> alias ATTR_INFO = Algebraic!(SourceFile, ConstantValue,  
>> Excepsion, Tuple!(Code,This[]), LineNumberTable, 
>> LocalVariableTable);
>
> - Please post such questions to the learn forum in the future.
> Noted. I will do that next time.
>
> I tried your suggestion and it fails silently; no error message 
> / stack trace.

I'd suggest using SumType 
(https://code.dlang.org/packages/sumtype) instead of std.variant, 
as the latter has its share of problems.

Otherwise, this kinda works, but can hardly be called anything 
but a horrible hack:

alias ATTR_INFO = Algebraic!(SourceFile, ConstantValue, 
Excepsion, Code,
                              LineNumberTable, LocalVariableTable);

struct Code
{
	size_t attribute_name_index;
	size_t attribute_len;
	size_t max_stack;
	size_t max_locals;
	size_t code_length;
	const(ubyte[]) code;
	size_t exception_table_length;
	Tuple!(size_t, size_t, size_t, size_t) exception_table;
	size_t attribute_count;
	private ubyte[] _attributes;
}

ref ATTR_INFO[] attributes(return ref Code code)
{
     return *cast(ATTR_INFO[]*)&code._attributes;
}

It will need some fixing if you have any destructors, as Code 
treats those ATTR_INFOs as just a bunch of bytes, but it will 
make the code compile and it might be good enough. Seriously 
though, check out SumType instead.

--
   Simen