On Thursday, 24 December 2020 at 14:31:22 UTC Jan Mercl wrote:
> On Thu, Dec 24, 2020 at 3:12 PM Arnaud Delobelle <arn...@gmail.com> > wrote: > > That's interesting, thanks. Although I don't think it fits my use case > because I need something stronger than an iterator: a function that given a > table and a key returns the next key in the table (as this is a public API > that Lua provides, see https://www.lua.org/manual/5.3/manual.html#pdf-next). > From my point of view this is an unfortunate API! Nevertheless it is what > it is... I haven't found even a hacky way to obtain that for a Go map. That > is why I think I need to make my own hashtable implementation > > The linked pdf seems to indicate that Lua's 'next' can be implemented > using Go range over a map with no problem because the iteration order > is undefined in Lua as well. > > What am I missing? > The order is undefined but stable (provided you don't insert new values), and accessible via the `next` function. Here is an example: $ lua Lua 5.3.5 Copyright (C) 1994-2018 Lua.org, PUC-Rio > t = { x = 1, y = 2, z = 3 } > next(t, 'y') z 3 > next(t, 'z') x 1 > next(t, 'y') z 3 > next(t, 'z') x 1 I don't understand how to do that with a map iterator unless get a new iterator each time and consume it till I get the key I want to find the next key for (which would be very inefficient), or there is a way to initialise the iterator at a given key - but I haven't found how to do the latter. Arnaud -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/31930063-9c33-4e0f-8372-ee5ae991b3e1n%40googlegroups.com.
