On Nov 6, 2009, at 6:38 PM, Russ Nelson wrote: > Michal Migurski writes: >> instead make sure that multi-level undo is completely bulletproof. > > To make life more interesting, OSM editing goes on concurrently, and > yet nearly everyone who is editing is editing a chunk locally. So OSM > is episodically being synched with chunks of data we call a > "changeset", but which also includes the concept of an "edit conflict" > meaning that two chunks have been edited at the same time. > > Simultaneous editing of geodata is currently not a solved problem. > Even less solved is the concept of multi-level undo, much less > single-level undo. Within an editing session? Sure. Within your > chunk of data? Sure. But not outside that.
I think this further underscores the difference between save mode and edit mode. Save mode is more like traditional desktop document editing, and the undo history need only be consistent with what you're doing in your own session. In this case, it should be possible to ditch the locked ways and instead make sure that the local document is fully self-consistent and undo-able. For live mode, clearly an undo feature would introduce more trouble than it's worth, for everyone involved in editing a particular area. There the presence of locked or ghosted ways as in the current Potlatch does make sense, but I do think the terminology and visual presentation could be tweaked a bit. I know what you mean about this not being a solved problem, and given how much time I spend with SVN, Git, etc. I'm pretty aware of how hard it can be to merge concurrent edits on the same resource. -mike. ---------------------------------------------------------------- michal migurski- m...@stamen.com 415.558.1610 _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk