Re: syntax sugar: std.path::buildPath instead of from!"std.path".buildPath

[bachmeier via Digitalmars-d]

On Tuesday, 14 February 2017 at 16:25:17 UTC, Andrei Alexandrescu 
wrote:
Range remove
(SwapStrategy s = SwapStrategy.stable, Range, Offset...)
(Range range, Offset offset)
if (s != SwapStrategy.stable
    && isBidirectionalRange!Range
    && hasLvalueElements!Range
    && hasLength!Range
    && Offset.length >= 1);

[...]

My recollection is past discussions got stalled because the 
approach is combinatorially bankrupt. How would one express the 
constraints of the functions above with simple named 
constraints? (Not rhetorical; please do provide an example if 
possible.) Before long there is an explosion in names 
("BidirectionalWithLvalueElementsAndLength", ...). This is what 
has buried not one, but two concepts proposals for C++, leading 
to the current Concepts Lite proposal. I haven't followed that 
lately but I remember it combines an engineering effort to 
reduce the number of names introduced (for the standard library 
only, which is a limitation) with adding support to Boolean 
logic (surprise, surprise) to the feature (see 
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4377.pdf), the most recent proposal, which was rejected for C++17. Over time, C++ concepts have moved from the broken combinatorially-bankrupt form slowly toward D's Boolean constraints (just with a gratuitously awkward notation). I presume they will be merged into the language when they'll have capabilities comparable to D's system.

The question is, given this experience, do we want to move the 
opposite direction?

I am not familiar with all of the past discussion of this issue, 
but something that I have wondered is why we can't do something 
like

alias fooConstraint = (s != SwapStrategy.stable
  && isBidirectionalRange!Range
  && hasLvalueElements!Range
  && hasLength!Range
  && Offset.length >= 1);

Range remove
  (SwapStrategy s = SwapStrategy.stable, Range, Offset...)
  (Range range, Offset offset) if fooConstraint;