[willbudd]

As a node in a tree hierarchy any folder can only have one parent folder. Tags of course allow nodes to have any number of parents (aka "associations").

The relationship between arbitrary nodes in a tree can be determined by tracing their common ancestry, but tags don't provide equivalent functionality, unless you strictly define how tags themselves relate to other tags. An obvious way to do so is to prescribe that every tag shall have exactly one parent (except for the root abstract "thing" tag).

In other words tags become folders, but any non-folder content of those folders can simultaneously live inside any number of folders. Similar to symlinks, but arguably less hacky, because there is no differentiation between "actual" location and "linked" location.

[jholman]

> Similar to symlinks, but arguably less hacky, because there is no differentiation between "actual" location and "linked" location.

In other words, similar to hardlinks

[willbudd]

Right, yes. True. I should have compared with hardlinks instead.

Minor detail: I intended for different deletion semantics from hardlinks. Whereas hardlinks use reference counting for that (only the last deletion actually deletes); for my purposes, delete anywhere meant delete everywhere.