Idea: limited template expansion

[David Nadlinger via Digitalmars-d]

On Thursday, 21 January 2016 at 13:36:28 UTC, Steven 
Schveighoffer wrote:
> On 1/20/16 6:01 PM, David Nadlinger wrote:
>> How would the client code be simpler with a built-in language 
>> feature?
>
> The use case I have in mind is a parser, let's say an xml 
> parser.
>
> […]

I still don't see how a language feature as described in your 
first post would make this any easier than using a template for 
that exact purpose (switching between methods to call).

If what you are trying to say is that you want the different 
template function instantiations to return incompatible types in 
addition to that, the feature from your initial post won't help 
you there either. Values can't have different types in 
non-template code, so you'd necessarily need to make the client 
code a template too. Streamlining the runtime -> compile time 
value dispatch process (as shown in your initial example) doesn't 
change the fact that the type of a given value cannot be 
influenced by runtime decisions.

  — David