- 16 Aug, 2021 1 commit
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tavit ohanian authored
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- 29 Jul, 2021 1 commit
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tavit ohanian authored
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- 12 Aug, 2019 1 commit
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Eric Myhre authored
No semantics change; this is a "sed refactor" in complexity. Literally: - `s/TraversalReason/VisitReason/g` - `s/TraversalProgress/Progress/g` - `s/TraversalConfig/Config/g` - `s/Traverse(/WalkMatching(/g` - `s/TraverseInformatively(/WalkAdv(/g` - `s/TraverseTransform/WalkTransforming/g` There's a few more internally, but the above covers all of the public exported interface changes. These changes generally reduce stutter (e.g. previously traversal.TraversalProgress was quite a gulp), and mostly result in shorter function names and signatures overall (and the signatures are particularly noticable, since VisitFuncs are often actually declared inline by calling code). A few docs strings also received manual touch-up. Signed-off-by: Eric Myhre <hash@exultant.us>
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- 12 Feb, 2019 1 commit
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Eric Myhre authored
All traversal/transform/selector/path code to date got a rethink. For the longest time, I was trying to keep all the traversal code in the main root IPLD package, thinking/hoping that the number of relevant functions would be minimal enough that this would be fine. Somewhere around the time where I conceded that yes, we *do* need separate methods for writable and readonly paths (it's true that readonly is a degenerate case of writable -- but they have different performance characteristics!), I gave up: the number of functions in play is too high to heap alltogether in the root package namespace. This leads to a number of other surprising results: namely, that ipld.Path *isn't* -- it's actually traversal.Path! We *don't use* paths anywhere else except as guidance to some forms of traversal, and logs and progress markers during traversal. Huh! Despite being initially surprising, I now regard this as a *good* code smell. ipld.Traversal as an interface and ipld.Path.Traverse are dropped. These turned out to be the wrong level of abstraction: it's both missing things, and not able to return enough things. By the time we would fix both, it's not an abstraction anymore. Path.Traverse didn't know how to use a link loader func -- and that's correct; it shouldn't -- and it also didn't retain and return a stack of Nodes it traversed -- which again, it shouldn't, because in general that would be useless overkill and resource waste... it's just that both these things are essential in some use cases. So! Cut that gordian knot. The Focus/FocusTransform/Traverse/TraverseTransform methods will now do all recursion work themselves, internally. The transform family will keep stacks of nodes encountered along the way, to aid in the (presumably) coming tree re-build; the focus family won't. All of these methods will be able to support link loading, though implementation of that is still upcoming. There's a few more fields in TraversalProgress, also preparing for when we have automatic link loading and traversal: we'll want to be able to inform the user's callbacks about load edges. (I'm not a fan of the term 'block' here, but running with it for the moment.) TraversalConfig is expected to grow. Namely, to include link loaders... and subsequently, probably block writers, as well! This is a big subject, though. It'll probably take several commits and possibly more than one iteration over time to hammer out a good API. One thing that's interesting to note that neither TraversalConfig nor TraversalProgress will grow to contain certain things: for example, a map of "seen" CIDs when doing link traversal. Why? Well, if you've been mentally modelling things as a graph, this is surprising; surely any graph traversal needs to remember a set of already-visited nodes. The trick is... we're *not* doing a graph traversal -- not exactly! Since our visitor gets a (Node,Path) *tuple*... it would be wrong to memoize on anything other than the complete tuple; and the Path part of the tuple means we're actually doing a *tree* walk rather than a graph walk. (And of course, since we're operating on DAGs, termination guarantees are already a non-issue.) Tada; no "seen" set. Signed-off-by: Eric Myhre <hash@exultant.us>
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