Units: a new pack for units and quantities

[kwon-young]

@ridgeworks

It wasn’t in the original CLP(BNR) ca. 1990 and, until now, no one has asked for it. It’s a trivial one liner to add it as a synonym to **. I will do so in the next release and can tell you how to patch your the version in your library if you’d like it sooner.

Thank you very much, I’ll also add support for ** on my end so that user are not surprised, probably switching to it by default.

[ridgeworks]

@kwon-young

I have just modified my qeval/1 predicate to this:

qeval(Expr) =>
   eval_(Expr, Q),
   (  (ground(Q.v) ; subsumes_term({_}, Q.v))
   -> call(Q.v)
   ;  call({Q.v})
   ).

And now it works

Just a couple of minor issues you might want to consider:

1. Q-expresssions (if I can call them that) of the form Var is Exp, where ground(Exp) is true, will be treated (unnecessarily) as a constraint. It doesn’t impact it’s logical correctness but constraint “compiling” adds overhead.
2. Given this upgrade, do you really need {...} Q-expressions anymore? (If not, keep it simple.)