Fun with templates

[Dicebot]

On Saturday, 6 July 2013 at 15:38:45 UTC, Artur Skawina wrote:
> Do you think this would be a problem /in practice/?

Yes. Honestly, lot of problems. I can easily imagine template 
function that modifies its argument in-place for a mutable 
qualifier and allocates a copy for an immutable one. Templates 
that introspect their parameter type to format some string. 
Different algorithms for processing mutable and immutable 
versions of same container.

And it is not just code breakage - you propose some magic instead 
of simple well-defined semantics and so far I don't even see the 
detailed description how new system should behave. Currently 
template body is defined only by its parameter set, your proposal 
changes that as far as I understand.

I think more reasonable approach is to define "inout" in template 
parameter specialization to mean "I don't care what it is, make 
it compiler error to rely on any behavior difference between 
them". Don't know what to do about mangling though. Will also 
most likely need to prohibit and direct reference to T.

It looks like extremely complex way to solve only one minor part 
of general problem (template bloat).