Extract template parameter at runtime?

[Yuxuan Shui via Digitalmars-d-learn]

On Monday, 15 June 2015 at 18:30:55 UTC, Steven Schveighoffer 
wrote:
> On 6/15/15 2:10 PM, Yuxuan Shui wrote:
>> I have a template class which is derived from a base class. Is 
>> it
>> possible to extract the template parameter from a reference to 
>> the base
>> class?
>
> No. You can't get compile-time information at runtime, unless 
> you have stored it somewhere that runtime can read.
>
> But perhaps you can further describe your requirement, and a 
> solution might be available.
>
> -Steve

Well I don't have a serious use case of this. I just started 
using D couple of weeks ago, and is now experimenting with it by 
writing a toy compiler.

What I'm doing is I'm abusing the D type system to represent 
types in my toy language. I store type information into template 
parameters, and when I need to type check, I just use typeid and 
compare the result. Now I want to generate different code when I 
encounter different types, and for that I want to get the 
template parameters.

Of course if this is not possible I can always go back to 
implement my own type system properly. It's just a good thing to 
have.