__WhereRef/WhereVal peeling, #ifdef and related experiments

Thomas W twhitmore.nz at gmail.com
Mon Jan 19 01:27:28 UTC 2015

Thanks Brian. As I noted, Maurizio's patch is not a real syntax..  just a
hack to take experimentation further.

Brian doesn't want to discuss syntaxes, nor was my intent to suggest such
-- just to move the concepts away from preprocessors, #ifdef and

There are many ways to slice type-casing; your example shows one (though
> you need a "meet rule" when you get to the multiple-tvar case), but there
> are others.

My post specifically raised the possibility of multiple-tvar cases, and
suggested a simple rectilinear approach in multi-dimensional space. There
would need to be order of precedence in match rules, but no interaction
would exist between separate clauses.

I'm having difficulty Googling an exact definition for "meet rule" -- if
you want to email a definition privately, I'd appreciate -- but apart from
most-specific L-to-R order of precedence, no such rule would be needed.

Let me know if anything is unclear.


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