Le 30/12/2022 à 15:07, David Kastrup a écrit :
Jean Abou Samra <[email protected]> writes:Le 30/12/2022 à 13:51, David Kastrup a écrit :However, it doesn't work right now for local variables, like function parameters, in #{ ... #}.I think you may underestimate the cost of magic involved with making #/$ integrate into local Scheme scoping. If you want Scheme semantics, $ offers those along with Scheme syntax.What is the cost of that magic precisely? In the basic case of \ being used outside #{ #}, the extra cost of \ being supported in #{ #} would be an assv-ref into an empty alist of closures, i.e., ~0 cost. While parsing #{ #}, we'd catch \ in addition to # and $. We already read the entire #{ #} for that. I don't think catching \ would add much overhead to it.You conflate "parsing" and "reading". For #{...#}, there is a rudimentary scan for # and $ that tends to deliver false positives (which then just don't get evaluated later on) and may get confused into overlooking actual positives. \ offers a lot more potential for getting this wrong.It would also make Guile evaluate one (lambda () <variable>) per use of \ in #{ #}, which I don't believe is costly.It is. The optimisation of not putting up closures for most constants made a relevant performance difference.While evaluating the \, the parser would need to do an assv-ref into the closure alist, which in most cases will have under 10 elements (the number of '#' / '$' / '\' in the #{ #} expression). If the linear cost of assv-ref is a concern, an obvious improvement is to use a hash table.The number of non-constant #/$ in a #{ ... #} will have a large hit rate of actually needed scoping. I don't see this for \xxx .Overall, I don't see what could have a worrisome cost. Did I miss something?See above. And there is absolutely no associated gain at all since $identifier will work just fine where scoping is needed. The gain of "people using Scheme but not understanding it might by chance escape trivial errors" is not really a gamechanger.
I'll reply on -devel, as we are getting off-topic for this list.
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