On Mon, Oct 26, 2020 at 8:05 PM John Cowan <xxxxxx@ccil.org> wrote:
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> "Beginning with ->" was a mistake.  I conflated two statements:  (a) I want to reserve -> and => (b) R6RS does not have a problem with either of these identifiers, even though identifiers are not allowed to begin with "-".  To which I add (c) that I don't care what we reserve, as long we reserve two things.
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> On Mon, Oct 26, 2020 at 5:30 PM Marc Nieper-Wißkirchen <xxxxxx@nieper-wisskirchen.de> wrote:
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>> How is this supposed to be efficient?
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> It's primarily intended to be complete.  Dynamically typed lists are a universal data structure; that's one of McCarthy's original theorems.  If you know how to match a list and you have views, you can match anything at all.
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>> This would construct an object just to have it deconstructed.
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> A very good point.  So let's make it (view view-proc pattern ...), where view-proc takes the object to match and returns multiple values that are matched against the patterns.
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Wait, is this like (match (view-proc obj) pattern ...)) ? Or
(from-view view-proc (match (to-view view-proc obj) (pattern ...))) ?

>>
>> If we want an efficient solution, the mapping from an opaque to a
>> transparent type should happen at expansion time.
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> If view-proc and call-with-values are inlineable, that's about as good as matching against any other pattern.
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> John Cowan          http://vrici.lojban.org/~cowan        xxxxxx@ccil.org
> Heckler: "Go on, Al, tell 'em all you know.  It won't take long."
> Al Smith: "I'll tell 'em all we *both* know.  It won't take any longer."
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